NEHRU ARTS AND SCIENCE COLLEGEDEPARTMENT OF MICROBIOLOGYMICROBIAL FOOD TECHNOLOGY

GROUP A - DIPLOMA IN QUALITY ASSURANCE IN MICROBIOLOGY DIPLOMAPAPER II : MICROBIAL FOOD TECHNOLOGY

UNIT I

Food as a substrate – Incidence and types of microorganisms in food – Contaminationand Spoilage of Meat, Poultry, Sea foods, Vegetables, Fruits. Principles of food preservations:Asepsis, Preservation by use of High temperature, Low temperature, Canning, Drying,Radiation and Food additives.

UNIT II

Food poisoning – Food borne diseases- Bacterial and Non- Bacterial. Fermented foods -Meat and fishery products – Country cured hams, Dry sausages,Katsuobushi. Fermented milkproducts – Butter, Butter milk, Sour cream, Youghurt, Cheese, Kefir, Koumiss, Taette andTarhama.UNIT III

In house Committee for quality assurance, Persons involved, Internal Microbial Qualitycontrol Policy, Quality Check at every step from collection of raw materials till it reaches thecustomer , Implementation of ISO standards and history, definitions, principles and use ofHACCP in Food Industry .UNIT IV

Indicator organisms – Direct examination – culture techniques – enumeration methods –plate – Viable & Total Count; Alternative methods – Dye reduction tests , electrical methods ,ATP determination: Rapid methods, immunological methods – DNA / RNA methodology –Laboratory accreditation.UNIT V

Food laws and regulations

A. National – PFA Essential Commodités Act (FPO, MPO etc.)B. International – Codex Alimentarius, ISO – 9000 series , ISO 22000 & BS 5750.C. Regulatory Agencies – WTOConsumer Protection Act - Relevance of Microbiological standards & criteria for food safety –Sampling plans – Microbiological guidelinesHygiene and sanitation in food sectorGeneral Principles of Food Hygiene, GHP for commodities, equipment, work area andpersonnel, cleaning and disinfect ion (Methods and agents commonly used in the hospitalityindustry), Safety aspects of processing water (uses & standards) and Waste Water & Wastedisposal

References:

James. M. Jay, 1992, Modern food microbiology 4ed.Frazier, W. C. and Westhoff D.C. 1989. Food Microbiology 8 ed.Dubey. R.C. and Maheswari. D.K. A Textbook of Microbiology, 1999. 1 ed.Water Analysis – A practical guide to Physico – Chemical & Microbiological waterexamination and Quality assurance – W.Schneider, W.Fresenius & K.E. QuentinSpringer – Verlag Pub. Heidelberg.Food Microbiology. 2 nd Edition – M.R.Adams & M.O.Moss – Panima Publishers.

UNIT-1

1.Define food microbiology.

The science that deals with the microorganisms involved in the spoilage, contamination, and preservation of food.

2.Explain how food serves as a substrate for micro organisms. What are the intrinsic factors of food that influence

microbial growth?

Food and microorganismsRELEVANCE OF MICROBIOLOGY Food serves as a interacting medium between various living species because, it is a source of nutrients for humans, animals as well as microorganisms. Food fit for human consumption is also a medium for the growth and activity of microorganisms. Hence human food is always associated with a variety of microorganisms. Since the primary function of microorganisms is self-perpetuation, they use the human or animal food as a source of nutrients for their own growth and activity. Microbial activity in a food can be beneficial in certain cases it leads to deterioration of the food and renders it unfit for human consumption. Four aspects of microbial activity are of relevance to processing and preservation of food.

Fermented foods Food chemicals from microorganisms Food poisoning & food borne diseases & Food spoilage.

Fermented foods:

Microorganisms can be used as processing aids in the production of fermented foods. New and modified foods with better shelf stability; palatability, flavour and organoleptic properties are produced by fermentation using specific microorganisms under controlled conditions.

Food chemicals from microorganisms:

A variety of food chemicals and additives produced by fermentation involving select species of microorganisms In addition, microorganisms themselves may be used as food. The biomass produced by fermentation can be harvested & used as a protein rich raw material for the formulation of foods.

Food poisoning & food borne diseases: Pathogenic microorganisms grow in the food utilizing the nutrients in the food & produce toxins, which are detrimental to the health of the consumer when such food is consumed. Food also serves as a vector or medium for certain pathogens that cause food infections & diseases.

Food spoilage:

The metabolic activity of various microorganisms not only utilizes the nutrients in food but also causes the spoilage of food through undesirable enzymatic changes affecting the quality of the food. The enzymatic changes include the formation of products, which contribute off-flavours & affect the organoleptic, textural and keeping qualities of food.

BACTERIA, YEAST AND MOULD:

Introduction:

Thousands of genera and species of microorganisms have been identified and classified. Several hundreds of these are associated in one way or other with food products. Many of them are of industrial importance as they find use in the production of new foods and food chemicals by fermentation and also in the preservation of food products. Microorganisms that are of importance in food microbiology include bacteria, yeast and molds.

Bacteria:

Bacteria are unicellular organisms of aerobic or anaerobic nature and exhibit many morphological forms. Three principal shapes have been well recognized, namely, spherical shapes of cocci, rod shape of bacilli and spiral form of Spirilla and Vibrios.

All bacteria associated with food are small in size, typically a few micrometers long and smaller in diameter. Bacteria form spores, which are seed like and far more resistant to heat, presence of inhibitory chemicals and other adverse conditions during food processing. Most bacteria multiply best at temperatures between 16 and 38C and are termed mesophilic. Psychrotropic or psychrophilic bacteria can grow at low temperatures while thermophilic ones can grow at higher temperatures.

Morphological characteristics important in food bacteriology:

One of the first steps n the identification of bacteria in food is microscopic examination to ascertain the shape, size, aggregation, structure and staining reactions of the bacteria present. The following characteristics may be of special significance.

ENCAPSULATION:

The presence of capsules or slime may account for sliminess of ropiness of a food. In addition, capsules serve to increase the resistance of bacteria to adverse conditions such as heat or chemicals. To the organism they may serve as a source of reserved nutrient.

FORMATION OF ENDOSPORES:

Bacteria of the genera Bacillus, Clostridium, Desulfotomaculum, Sporolactobacillus and Sporosarcina share the ability to form endospores. Of primary interest to the food microbiologists are the spore forming species of the genera Bacillus and Clostridium. Endospores are formed at an intracellular site, are very refractile, and are resistant to heat, ultraviolet light and desiccation.

Sporulation usually appears in the late logarithmic phase of growth, possibly because of nutrient depletion or product accumulation. During this transition of vegetative cell to spore, the spore become refractile, there is a massive uptake of Ca ions, and synthesis of dipicolinic acid(DPA) occurs, a compound absent from vegetative cells. The acquisition of heat resistance by the forming spore is closely correlated to the formation of DPA and the Ca 2+ uptake.

FORMATION OF CELL AGGREGATES:

It is characteristic of some bacteria to form long chains and of others to clump under certain conditions. It is more difficult to kill all bacteria in intertwined chains or sizable clumps than to destroy separate cells.

Cultural characteristics important in food bacteriology:

Bacterial growth in and on foods often is extensive enough to make the food unattractive in appearance or otherwise objectionable. Pigmented bacteria cause discolorations on the surface of liquids, growth may make surfaces slimy, or growth throughout the liquids may result in undesirable cloudiness or sediment.

Physiological characteristics important in food bacteriology:

The bacteriologist is concerned with the growth and activity of bacteria and other organisms in food and with the accompanying chemical changes. These changes include hydrolysis of complex carbohydrates to simple ones, hydrolysis of proteins to polypeptides, amino acids and ammonia or amines and hydrolysis of fats to glycerol and fatty acids.

O.R rxns, which are utilized by the bacteria to obtain energy from foods, yield such products as organic acids, alcohols, aldehydes, ketones and gases. A knowledge of the factors that favour or inhibit the growth and activity of bacteria is essential to an understanding of the principles of food preservation and spoilage.

Genera of Bacteria important in food Bacteriology:

Bacteria that play significant roles in foods are often grouped on the basis of their activity in foods without regard to their systemic classification.

Lactic acid bacteria ferment sugars to lactic acid and include species belonging to genera of Leuconostoc, lactobacillus, streptococcus and pediococcus. Their activity is desirable in a variety of foods such as sauerkraut and other pickled vegetables and dairy products for the production of flavour. They cause spoilage of wines.

Acetic acid bacteria oxidize ethanol to acetic acid. Species of genera Acetobacter and Gluconobacter are the most common. They are useful in vinegar manufacture but ate undesirable in alcoholic beverages.

Butyric acid bacteria are mostly the spore forming anaerobes of the genus clostridium. They produce butyric acid by fermenting sugars. Propionic acid bacteria produce propionic acid andbelong the genus propioni bacterium.

Proteolytic bacteria include a heterogenus group of bacteria, which produce extracellular proteases. Most species belonging to the genera of clostridium, Bacillus, pseudomonas and proteus.

Lipolytic bacteria are also a heterogeneous group of bacteria, which produce lipase. Organisms of the genera pseudomones, Alcaligens, Staphylococcus, Serratia and Micrococcus are lipolytic.

Saccharolytic bacteria ydrilyze disaccharides and polysaccharides to sampler sygas. Ex: Bacillus subtilis and Clostridium butyrium, which are also amylolytic.

Pectinolytic bacteria produce pectinases responsible for softening of plant tissues of loss of getting power in various plant foods. Ex: Bacillus, Achromobacter, Aeromonas, Arthrobacter and Flavobacterium are pectinolytic.

Thermiphylic and thermoduric bacteria are resistant to high temperature. Thermophilic bacteria are resistant. Cause spoilage of low acid canned foods. Important species include Bacillus steresthermiphilus and with thermosaccharoluticum. Thermiduric organisms survive heat treatment such as pasteurization. Ex: Bacillus, clostridium,Micrococcus streptococcus Lactobacillus and Mycobacterium are found in foods.

Psychrotrophic bacteria are able to survive and grow at refrigeration temperatures through their optimum temperatures of growth in around 20 to 30oc. Ex: Pseudomonal, Achromobacter, Alcaligenes and Flavobacterium are psychrotophic.

Halophilic bacteria include species of the genera Bacillus, Micrococcus, Vibrio, Moraxella, Halobacterium organisms require certain minimal concentrations of dissolved Nacl for their growth and survive at higher concentration of salt.

Osmophilic or saccharophilic bacteria grow in high concentrations of sugar. Ex: Leuconostoc species.

Pigmented bacteria produce colours during their growth in foods. Ex: Flavobacterium (yellow to orange), Serratia(red),Halococcus (red to orange) and Halobacterium (pink, red and orange), Lactobacillus plantarum produces rust colour pigment discolouring cheese. Flavobacterium species causes discolouration on the surface of meat and spoilage of Shell fish, poultry, eggs, butter and milk.

Slime or rope forming bacteria include Alcaligenes viscolactis, Enterobacter aerogenes and Klebsiella oxytoca and some species of streptococcus and Lactobacillug plantarum causes ropiness or ropiness in milk.

Gas forming bacteria include species of the genera of Leuconostic, Lactobacillus and propionibacterium which produce carbon-di-oxide species of Eschericbis, Enterobacter proteus, bacillus and Clostridium produce both carbon-di-oxide and hydrogen.

Off-flavour forming bacteria include those of genus streptomyces which produc undesirable flavours and musty of earthy odour and taste. Manu species of pseudomonas produce a variety of metabolites that affect the flavour of foods deleteriously.

Coliform bacteria ex. Escherichia coli and Enterobacter aerogenes. They cause spoilage of a variety of foods producing off-flavours and sliminess.

Some of the important disease causing bacteria include the following:

Which batulinum produces a neutotoxin in canned meat products and causes the fatal disease botulism.Corynebacterium species includes the diphtheria organism which diptheriae.Erwinia species are plant pathogens and damage plants and plant products causing bacterial soft rot.E. C oli species includes some serotypes which are pathogenic to humans.Myco bacterium species includes the tubercle bacilli M. tuberculosis that causes tuberculosis especially through raw milk from infected cows.Salmonella species are enteric pathogens that grow in foods and cause food infection.Shigella species is transported by foods and causes bacittary dysentery.Staphylococcus species includes the important S.aureus which produces an enterotoxin causing food poisoning.Streptococcus species includes pathogenic S.agalartide which causes mastitis in cows and S.pyogenes which causes septic sore throat, Scarlet fever and other diseases in humans. Vibrio species is pathogenic to humans.

3.EXPLAIN ABOUT THE GENERAL CHARACTERISTICS, CLASSIFICATION AND IMPORTANCE OF MOULDS, YEAST AND BACTERIAGENERAL CHARACTERISTICS OF MOULDS IN FOOD MICROBIOLOGY.

1) Moulds are multicellular , filamentous fungi whose growth is recognized by its fuzzy or cottony appearance.2) They may be of white, coloured or dark or smoky.3) The thallus or vegetative body is characteristic feature of moulds.

MORPHOLOGICAL CHARACTERISTICS:I. HYPHAE AND MYCELIUM:

Hyphae à tubular, filamentous structure Mycelium à interwined hyphae Submerged hyphae à growing within the food Aerial hyphae à growing into air above the food

Sclerotia à tightly packed masses of modified hyphae, often thick-walled. à More resistant to heat

Septate à cross wall dividing the hypha into cells Aseptate à no cross walls Apical growth à septate hyphae increase in length by means of divisison of the

Tip cell

. Intercalary growth à division of cells within hyphae

II. REPRODUCTIVE STRUCTURES OF PARTS: Asexual spores à conidia àArthroconidia

àSporangiospores

àChlamydospores

Sexual spores àOosporesàZygospores

àAscospores

àBasidiospores

III. CULTURAL CHARACTERISTICS: Loose & fluffy, compact growth. Upper surface à may be velvety, dry, powdery, wet or gelatinous. Pigmentation à red, purple, yellow, brown, gray, black.

IV. PHYSIOLOGICAL CHARACTERISTICS:Moisture requirements – 14 to 15%

Temperature requirements – mesophiles(25 to 30·c)

– psychrophiles(-5 to -10·c)

– thermophiles(above 40 to 60·c)

Oxygen & pH requirements -- aerobe, pH 2 to 8.5

Food requirements -- from simple to complex

Inhibitors -- fungicidal / mycostatic produced by certain moulds

CLASSIFICATION AND IDENTIFICATION OF MOULDS:

Kingdom : Myceteae

Identification:

1. Hyphae septate or aseptate.2. Mycelium clear or dark.3. Mycelium coloured or colourless.4. Sexual spores à oospores, zygospores or ascospores.5. Asexual spores à Sporangiospores, conidia or arthrospores (oidia)

6. Characteristics of the spore head:a) Sporangia à size, colour, shape, location.b) Spore heads bearing conidia à single conidia, chains, budding conidia or masses, shape and arrangement of

sterigmata or phialides etc.,2. Appearance of sporangiophores or conidiophores.3. Microscopic appearance of asexual spores.4. Presence of special structures à stolons, rhizoids, footcell ,apophysis, chlamydospores, sclerotia etc.

Classification:

Division : Zygomycotina

Class : Zygomycetes (non septate mycelium, reproduction by sporangiospores, rapid growth)

Order : Mucorales

Family : Mucoraceae

Genus : Mucor

Rhizopus

Thamnidium

Division : Ascomycotina

Class : Pletomycetes(septate mycelium, ascospores(8))

Order : Eurotiales

Family : Trichocomaceae

Genus :Byssochlamys

Eupenicillium

Emericella

Eurotium

Division : Deuteromycotina

1. Class : Coelomycetes

Genus : Colletotrichum

2. Class : Hypomycetes (hyphae give rise to conidia )

Order : Hypomycetales

Family : Moniliaceae

Genus : Alternaria

Aspergillus

Aureobasidium ( Pullularia )

Botrytis

Cladosporium

Fusarium

Geotrichum

Helminthosporium

Monilia

Penicillium

Stachybotrys

Trichothecium

ORGANISM CHARACTERISTICS FOOD SPOILAGEMUCOR:M.racemosus

M.rouxii

RHIZOPUS:R. stolonifer

(bread mold)

THAMNIDIUM T. elegans

ASPERGILLUSA. glaucus

A. repens

A. niger

Non – septate hyphae.

Sporangium with sporangiospores.

No rhizoids / stolon.

Non septate hyphae.

Stolons & rhizoids.

Rhizoids are seen, sporangium with sporangiospores.

Sporangium with sporangiospores from sporangiophore.

Grows well in high sugar & salt conc.

Conidia are green, Ascospores are in asci.

Spores are large, tightly packed, black, brownish, black, purple brown & Conidia are rough with pigment & are in chains.

Ripening of cheese.

Whiskers on beef & black spots (frozen milk).

Spoilage of berries, fruits, vegetables, bread, apples.

Black spot on beef & frozen mutton.

(watery soft rot)

Chill storaged meat – whiskers.

Spoilage of grape jams & jellies.

Commercial production of citric, gluconate, enzyme production

A. flavus oryzae

PENICILLIUMP.expansumP. digitatum

P.camemberti

P.roqueforti

P. italicum

NEUROSPPORA(Monilia)

N. sitophila

SPOROTRICHUMS. carnis

BOTRYTISB. cinerea

GEOTRICHUM(Oospora/ Oidium)G. candidum(O.lactis) – Dairy mold

CLADOSPORIUMC. herbarum

HELMINTHOSPORIUM

ALTERNARIAA. citriA. tenuisA. brassicae

FUSARIUM

TRICHOTHECIUMT. roseum

AUREOBASIDIUM(Pullularia)

Conidia are yellow to green in colour & produce aflatoxin.

Blue-green spared mold

Olive/yellow-green conidia

Grayish conidia

Bluish-green conidia

Blue green conidia

Budding conidia with conidiophore

Conidiophore with conidia

Conidiophore with swollen tips producing conidia septate mycelium

Septate hyphae, Arthroconidia.

Imparts flavour & aroma to cheese

Dark molds, septate hyphae.

Growth is velvety, Olive coloured to black, Conidia are lemon shaped.

Black rot of peach, figs, citrus.

Soft rot of fruit

Soft root of Citrus

Ripening of camembert cheese

Ripening of blue cheese

Rotting of citrus fruit.

Red bread mold – pink, loose textured growth on bread.

Grows on sugarcane bagasse.

Seen on chilled meat causing white spots.

Disease in grapes – Gray mold of apples, pears, citrus, grapes.

Sour rot of citrus, peaches.

White to cream coloured growth.

Dairy cream, Meat & vegetables.

Black spot on the foods (beef), spoil butter.

Root on stone fruits, black rot of grapes.

Plant ppathogen, Saprophytes on vegetables

BYSSOCHLAMYSB. fulva

A.A.

-

Septate mycelia, Brown, many celled conidia are in a chain on the conidiophore

Conidiophore produces conidia are of macro & microconidia.

Septate hypphae with conidiophores & produces mycotoxins.

Yeast like colonies

Asci with ascosporesHeat resistant

Soome sps produce mycotoxins, Rotting citrus ( stem & black rot ) fruit, Black rots of stone fruits, apples, figs.

Grown on foods, Brown rot of citrus fruit & Pineapples, soft rot of figs.

Pink rot of fruits.

Blackk spot on beef, fruits & vegetables.

Spoilage of high acid canned foods.

Spoil canned & spoiled fruits.

4.Explain about the factors influencing the growth of micro-organisms.

FACTORS INFLUENCING THE GROWTH OF MICRO-ORGANISMS Interactions between microorganisms and our foods are sometimes beneficial. Food is the substrate, for the growth of

microorganisms. The type of microorganisms present and the environmental conditions are also important. The food or substrate dictates

what can grow and cannot grow. The characteristics of the food or substrate one can make predictions about the microbial flora that may develop. The factor that favor or inhibit the growth of microorganisms is essential for the principles of food spoilage and

preservation. The chief compositional factors of a food that influence microbial activity includes:

1. INTRINSIC FACTORS 1. pH 2.Moisture content 3. Oxidation –reduction potential (Eh)

4. Nutrient content 5.Antimicrobial constituents

6.Biological structures2. EXTRINSIC FACTORS 1. Temperature

2. RH of the environment 3. Presence or concentration of gases in the environment

INTRINSIC FACTORS:The parameters of plant and animal tissues that are inherent part of the tissues are referred to as intrinsic factors.

1. Hydrogen ion concentration pH:PH is one of the main factors affecting the growth of survival of microorganisms in culture media

and in foods.

Example:- When pure water ionizes equal number of OH – and H+ are produced. Only a small amount of water ionizes so that the concentration of these ions is very small, -1 X 10^-7 mol/L. This can be summarized as follows:

H2O > OH- + H+[H+] =[OH-] = 1 X 10^-7 mol/LS solution containing equal number of H+ and OH – ions is neutral in reaction. A solution containing more H+ ions

than OH- ions is acid.A solution containing more OH- than H+ ions is alkaline.

Example:- A solution containing 10^-7 mole H+/L has a pH of 7 and is neutral. A solution containing 10^-5 mole H+/L has a pH of 5 and is acid. A solution containing 10^-8 mole H+/litre has a pH of 8 and is alkaline.pH RANGES FOR MICRO-ORGANISMS:-

All microorganisms have a pH range in which they can grow and an optimum pH at which they grow best. Saccharomyces cerevisiae, for example has a pH range of 2.35 – 8.6 with an optimum at pH 4.5.

pH not only influence the growth rate of an organism within its pH range but is also has an overall influence on the growth curve. This is illustrated in Fig. 6.10, which shows the effect of pH on the growth curve. Notice that is pHs below the optimum:

EFFECT ON pH ON THE GROWTH RATE OF BACTERIA, YEAST, AND MOULDS

growth rate decreases; the maximum number of cells produces drops; the length of the lag phase increases; the length of the stationary phase shortens; the death rate increases.

The temperature of the environment (incubation determines the pH minimum for an organism temperature in the laboratory), the nutrients that are available, the water activity and the presence of inhibitors.

HOW DOES pH AFFECT MICROBIAL CELLS?The internal pH of cells is maintained near to pH 7.0(this may be lower in some organisms,

e.g., yeasts in which the cells pH has been measured at pH 5.8) and is the pH at which cells metabolism works best.Cells membranes are impermeable to H+ and OH- ions and, in addition, cells may have a mechanism to pump out H+

ions.

When organisms are subjected to pHs outside their optimum but within the growth range, K+ and OH- ions affect the outer layers of the cells but not the internal pH. pHs above and below the optimum for growth may affect the following: The enzymes (permeases) need for the uptake of nutrients, including essential ions. The production of extra cellular enzymes and their subsequent activity when released. The mechanism of ATP production in the bacteria, which involves the cell membrane.

When the microbial cell is subjected to extreme pHs cell membranes become damages. H+ and OH- ions can then leak into the cell where enzymes are denatured and nucleic acid molecules are denatured, leading to cell death.

The effect of weak acids on microbial cells is temperature dependent. At concentrations that inhibit growth and cause cell death, they have less effect as the temperature is lowered.

The order of activity of acids in terms of their antimicrobial effect isPropionic > acetic > lactic > citric > phosphoric > hydrochloric.

pH and the growth of micro organisms in foods.Foods are quire variable in terms of their pHs. Most are acidic ranging from the very acidic to almost neural in

reaction.

pH changes in foods due to the activity of micro-organisms. Milk sours as a result of latic acid production by streptococi and lactrobacilli. pHs of foods

Food pH Food pHLemon 2.2-2.4 Meat 5.4-6.9Strawberry 3.1-3.9 Halibut 5.6Tomato 3.9-4.6 Lettuce 6.0Pear 3.7-4.7 Cod 6.2-6.6Banana 4.5-4.7 Milk 6.3-6.6Carrot 5.0-6.0 Egg white 8.6-9.6Potato 5.3-5.6

Strong inorganic acid is not often included in processed foods but hydrochloric and phosphoric acids are used in the manufacture of carbonated and non-carbonated drinks. Coals, for example, contain phosphoric acid.

pH ranges for food poisoning bacteria.Organism Minimum Optimum MaximumStaph, aureus 4.0 6.0-7.0 9.8Clostridium perfringens 5.5 7.0 8.0Listeria monocytogenes 4.1 6.0 – 8.0 9.6Samlonella spp 4.05 7.0 9.0Vibro parahaemolyticus 4.8 7.0 11.0Bacillus cereus 4.9 7.0 9.3Campylobacter 4.9 7.0 9.0Yersinia 4.6 7.0-8.0 9.0Clostridium botulinum 4.2 7.0 9.0

2. Water activityWater in the liquid state is essential for the existence of all living organisms. The cells of living organisms have very

high water content, i.e., more than 75%. The amount of water is required to maintain the cell in an active state, and without liquid water living organisms, including micro-organisms, will not grow or reproduced.

The ways in which water can become unavailable for growth are: The water contains dissolved solute such as sugar or salts. The water is crystallized as ice. The water is present as water of crystallization or hydration. The water is absorbed on to surface (matrix effects).

The amount of water available for microbial growth in terms of the water activity is the amount of water available in a food(or other materials) for microbial growth. More precisely:

Vapour pressure of a substance or solution Water activity = ------------------------------------------------------------

Vapour pressure of water at the same temperature

The amount of water available to microorganisms in foods is normally indicated in terms of water Activity the water content is referred to as Equilibrium relative humidity (ERH) atmosphere above a food at equilibrium with the food and is equal to the aw X 100%. Raoult’s law be used to calculate the water activities.THE WATER ACTIVITY OF FOODS:-

The water content of a food may be bare little relationship to its water activity. Fresh meat, for example, has a water content of 75% but a water activity of 0.98. Muscle protein and fat are the bulk of the solids present. These are not soluble in water, have little surface effect and therefore do not contribute in any major way to the water activity. Water soluble materials (glucose, amino acids, mineral salts and vitamins) are present in such small quantities that the water activity of fresh meat is very high.

Foods may have low salt content but low water activity.THE EFFECT OF WATER ACTIVITY ON MICRO-ORGANISMS:-According to Raoult’s law:

naw = ------------

N + n

Where n is the number of moles of solute and N the number of moles of solvent (water)Another, more useful way of writing the equation is :

Xerophiles (Organism loving dry conditions). This term applied specifically to a group of moulds (Xerophilic moulds) that can grow under very dry conditions, i.e., environments with water activities as low as 0.61. They will not grow at water activities higher than about 0.96 and their optimum water activity is in the region of 0.9 – 0.85. These organisms can cause spoilage of dries and salted fish, for example, the mould Xeromyces bisporus.

Halophiles (Salt-loving organisms). a. Moderate halophiles are organisms that require sodium chloride but will grow only at moderate concentrations, i.e. between

1 and 10% Sodium ions are believed to be involved with the transport mechanisms associated with the cell membrane and the uptake of materials from the environment. For example, Vibrio parahaemolyticus, 1-8% sodium chloride.

Effect of water activity on microorganisms:b. Extreme halpohiles are organisms that will only grow at high

sodium chloride concentrations. Unlike most other bacteria, their cell walls are made of protein. Na + ions appear to form ionic bonds that maintain the stability of these proteins and therefore the structure of the wall. At high salt concentrations the cell wall is rigid and the cells take on a cylindrical shape. As the concentration of Na+ in the environment decreases the cell shape becomes more and more rounded until the cell wall disintegrates and the cells lyse. This happens when the sodium chloride concentration in the environment reaches about 12% Halobacterium Salinarum is associated with the spoilage of salted fish.

Halotolerant (haloduric) organisms: These organisms are able to grow at high sodium chloride concentration but do not have a specific requirement for sodium chloride like the halophiles.Example:- Staphylococcus aureus can grow at sodium chloride concentrations as high as 20%(aw 0.83). Pediococcus halophilus can grow at 20% sodium chloride (aw 0.83)

Osmophilic yeasts:- ( yeasts loving high osmotic pressures) certain yeast that will grow where the water activity is low. Example:- Saccharomyces rouxii (Zygosaccharomyces rouxii) will grow at sugar concentration of 70% and above (aw 0.62).Saccharomyces rouxii can be responsible for the spoilage of foods with high sugar concentrations, eg., soft-centered chocolates.

Osmotolerant organisms:-This terms is applied to organisms (mainly yeasts) that grow best at high water activities but are also tolerant of high sugar concentration can grow at sugar concentrations of 60% and above.

The effect of water activity on the growth curve isProduces a slower growth rate;Increases the length of the lag phase; Causes the production of fewer cells when the stationary phase starts; Causes cells to die more rapidly during the death phase. Principle groups of foods and their water activity

S. No Aw valve Food involved S. No Aw valve Food involved

1 0.98 and above

Fresh meat and fishFish fruits and vegetablesMilk and most beveragesCanned vegetables in brineCanned fruits in light syrup

4 0.60-0.85

Dried fruitsFlourCerealsJams and jelliesNutsSome aged cheeseIntermediate moisture foods

2 0.93-0.98

Evaporated milk Tomato pasteProcessed cheeseBreadCanned cured meatsFermented sausageCanned fruits in heavy syrupGouda cheese

5 Below 0.60

ChocolateHoneyBiscuitsCrackersPotato chipsDried eggsMilk and vegetables

3 0.85-0.93

Dry or fermented sausageDried beefRaw hamAged cheddar cheeseSweetened condensed milk

Factors affecting the water activity of foods:1. Kinds of solute:

Gel aW increases. Sugar aW decreases

2. Nutritive value of food: The better the medium for growth the lowest the limiting aw.

3. Temperature: Temperature increases aW decreases Temperature decreases aW increases

4. Oxygen supply: Oxygen increases aW increases Oxygen decreases aW decreases

5. pH: pH decreases and aW increases survive pH decreases and aW decreases organism donot survive.

6. Inhibitors: Salt / sugar concentration inhibits aW. Water tie up with ions so aW decreases. Organism donot survive due to osmosis.

3.Oxidation – reduction potential: Oxidation reduction potential or redox potential (OR or Eh) is a measure of whether microbial/material has a

tendency to gain electrons 9become reduced) or lose electrons (become oxidized). Microorganisms vary in their requirement for oxygen and their response to the presence of oxygen in the

environment.1. Aerobic -Requires oxygen in order to generate cellular energy in the form of ATP.2. Anaerobic:(negative Eh values) - Generate cellular energy without oxygen.3. Obligate aerobe: (positive Eh value)

Requires oxygen for growth.Energy production is by glycolysis, Kreb’s cycle.Organic substrate oxidize to give CO2 and H2O (38 ATP).Eg: Pseudomanas fluorescens, Penicillium sp., Pichia sp., Hansenula sp..

4. Microaerophiles :Requires oxygen in minimum quantity eg. Campylobacter sp.1 – 10%, Optimum – 6%

Oxygen concentration above 10% is toxic & kills the organism. 5. Facultative anaerobes:

Grows in the absence of oxygen. Energy production is by glycolysis, Kreb’s cycle Eg. Saccharomyces cerevisiae produces 38 ATP. Eg. for food poisoning bacteria – S. aureus, E.coli.

6. Obligate anaerobes:Donot require oxygen eg. Clostridium botulinum, Cl. perfringens.

Redox of foods & Microbial growth:The actual redox of food will depend on a number of factors :

1. the oxygen concentration in the environment of the food & its access to the food.2. Density of the food structure, which affects the ability of oxygen in the environment to penetrate.3. Concentration & types of reducing substances in the food that resist changes in redox towards the positive.

Resistance to change in redox in a food is known as poising capacity.4. The way in which the food is processed.5. The pH of food. For every unit decrease in pH the Eh increases +58mV.

The surface of solid foods in contact with the air will have a positive redox whereas the interior may be negative.Eg. Carcass meat exterior - +ve200 mV [aerobes, facultative anaerobes]

Interior - -ve150mV Processing & mixing may alter the redox Eg. Milk during milking & processing [microaerophiles] Heating drives off oxygen & may increase quantity of reducing substances in a food. Eg. Canned foods negative redox (obligate anaerobes, facultative anaerobes, oxygen independent

organism).

Spoilage of canned foods Eg. Rhizopus sp. Byssochlamys fulva .4. Nutrient content:

These are based on : Foods for energy – Carbohydrates, Fats, Proteins, Esters, Alcohols, Peptides, Aminoacids, organic acids. Foods for growth _ Nitrogen containing foods. Accessory food substances or vitamins.

5. Inhibitory substances & Biological structure: Generally foods have some inhibitors: Eg. Freshly drawn milk – Lactinins, Anticoliform factors. Egg white – Lyzosyme. Canberries – Benzoic acid Propionibacterium – Propionic acid in Swiss cheese inhibits molds. Streptococcus lactis – Nisin which inhibits lactate fermenting organism. Lactobacillus inactivates nisin.. Yeast – Resistant to SO2

Heating lipids leads to autooxidation & concentrated sugar syrups during browning results in production of furfural & hydroxy methyl furfural which are inhibitory to fermenting organisms.

Food has certain shell / outer covering which prevents the entry of organisms called as biological structures. Eg. Egg shell (vitelline) , Fish[scales], Fruits & vegetables[outer skin].

EXTRINSIC FACTORS:The extrinsic parameters of those properties of the storage environment that affect both the foods and their

microorganisms.1. Temperature:-

Micro organisms are capable of active growth at temperatures well below freezing to temperatures above 1000c.But each individual species has a far more restricted temperature range in which it can grow. The range is determined largely by the influence that temperature has on cell membranes and enzymes and, for a particular organisms, growth is restricted to those temperature at which its cellular enzymes and membranes can function.

The relationship between growth rate and temperature for many microorganisms can be is illustrated.

A is the minimum temperature, i.e., the temperature below which no growth occurs. At temperatures below the minimum, the properties of cell membrane change so that they can no longer transport materials into the cell.

B is the optimum temperature, i.e., the temperature at which the organisms grows at its fastest rate. C is the maximum temperature, i.e., the temperature above which no growth occurs. At temperature above the maximum

enzymes become denatured and cease to catalyze essential cell reactions. These temperatures also damage the proteins and lipids in the cell membrane, which cease to function normally. So membrane collapse and the cell breakdown (thermal lysis).

The Cardinal temperature for Escherichia coli is

Minimum : 8oC Optimum : 28oC Maximum: 47oCThe minimum and maximum temperatures for growth normally quoted for an organisms depend on the Other factors that influence growth also operating at an optimum, e.g., pH and water activity. If these environmental factors move way from the optimum then the minimum temperature for growth will increase and the maximum temperature decrease. For example,The minimum growth temperature for the food poisoning organism Staphylococcus aureus is 6.7oC and the maximum 48oC when the organism is grown at the optimum ph of 7.0 and optimum water activity of 0.99. if the pH of the environment is reduced to pH 5.0 and the water activity reduced by the addition of 3.0% sodium chloride to the growth medium, then the organism will no longer grow at 48’C and the minimum temperature is increased to 30’C

On the basis of their cardinal temperatures for growth, microorganisms can be divided into five groups:

Mesophiles Obligate psychrophiles Psychrotrophs Thermophiles Extreme thermophiles

Some microbiologist in factor, recognize a sixth category; facultative thermopiles, i.e., organisms that

have an optimum in the mesophilic zone but can grow well into the zone in which thermopiles grow rapidly.

Groups of Microorganisms based on growth temperatures.

Group Minimum0C Optimum oC Maximum oC

Obligate psychrophiles -10 10-15 20

Pshychrotophy -10 20-30 42

Mesophile 5 28-43 52

Thermophile 30 50-65 70

Extreme thermophile 65 80-90 100

Mesophiles (organisms adapted to growth in the middle Temperature Zone)

Adaptation man and other warm-blooded animals, and water in tropical and temperature climates. An important characteristic of mesophiles is their lack of ability to growth at chill temperature (-1 to 5’C).

Example:- Bacteria, Yeasts & moulds

Many food spoilage organisms are also mesophilic.

Temperatures for toxin production by Staphylococcus aureusObligate psychrophiles(cold loving organisms)

Adaptations=> Arctic and Antartic Oceans, and land masses where temperatures are low throughout the year(land below 0’C and oceans 1-5’C).

Example:-Flavobacterium

PSYCHROTROPHS(ORGANISMS FEEDING AT LOW TEMPERATURE)

Adaptation => water and soil in temperate climate(relatively high summer temperatures and low winter temperatures). Minimum temperatures recorded for bacteria in this group are as low as –6.5 oC (Pseudomonas fragii), - 10 oC(moulds) and –12.5 oC( the yeast Debariomyces hansenni).

Psychrotrophs are called facultive psychrophiles, referring to psychrophiles with the ability to grow at relatively high temperatures.

Psychrotrophs are a very important group of organisms causing the spoilage of foods hed at chill temperatures either on melting ice or in the refrigerator.

BACTERIA YEAST MOULDSPseudomonas Candida Penicillium

Alteromonas Torulopsis Aspergillus

Shewanella Saccharomyces Cladosporium

Bacillus Debariomyces Botrytis

Clostridium Rhodotorula Alternaria

Lactobacillus Trichosporon.

In psychrotrophs, a higher amount of unsaturated fatty acid appears to maintain the plasma membrane in a liquid and mobile state at temperature below 5 oC. This ensures that the membrane is biologically active and capable of absorbing nutrients at low temperature.

THERMOPHILES(ORGANISMS LOVING HIGH TEMPERATURES)

Thermophiles are active in soils heated by sunlight compost heaps and silage, where the temperature can reach as high as 70 0C. Thermophiles are responsible for the spontaneous combustion of straw and hay. When the hay becomes damp, mesophiles grow; their metabolic processes generate heat and, because of the high level of insulation in the stack, the temperature moves up into the thermophilic zone .Growth of thermopiles takes over, increasing the temperature even further (up to 70 0C plus), when chemical oxidation causes the stack to spontaneously combust.

Few thermophiles have any significance in foods. Bacillus stearothermophilus, Clostridium thermosaccharolyticum and desulfotomaculum nigrificans(Clostridium nigrificans) are bacteria that cause the spoilage of canned foods stored at elevated temperatures that allow thermophiles to grow.

Three factors seems to be involved:

The cell membrane of thermophiles are abnormally stable because of a high content of saturated fats. Cells proteins, including enzymes, are unusually heat stable. The ribosomes are heat stable.

What effect does temperature have on the lag phase of growth?

Temperature has a very important effect on the lag phase of growth. As the temperature moves towards the minimum, not only dies growth rate decrease but the length of the lag phase increases. This has important consequence in relation to the preservation of foods at chill temperatures. The increase in storage life of foods held at chill temperature is associated not only with a decrease in the growth rate of spoilage organisms but also in an extension of the lag phase, when the population is not increasing in size. This increase in the length of the lag phase may be as important as decrease in growth rate. The effect of temperature on length of the lag phase and the rate of growth of psychrotroph is illustrated. The effect is not linear. A psychrotroph having a lag phase of 1 hour at its optimum(25 0C) may have lag phase of 30 hours at 5 oC and 60 hours at 0 oC. At temperatures very close to the minimum, lad phases may become very long indeed; 414 days has been recorded for some organisms.

CHILLING INJURY:-Microbial cells can be damages when they are cooled from ambient to chill temperatures, a phenomenon known as

chilling injury. There are two types of chilling injury. Cold shock (Direct chilling injury) is associated with the process of cooling foods from ambient temperature to chill

temperature. The level of injury depends on the rate at which the food is cooled. More cell damage occurs at slow rates of cooling than with fast rates. This type of damage seems to be caused by changes in the structure of the cell membrane resulting in the leakage of important cell metabolites, e.g., amino acids and ATP from the cell. Actively growth cells are more susceptible than stationary phase cells.

Indirect chilling injury is associated with holding food at chill temperatures for prolonged periods(several days) and is independent of the rate at which the food has been cooled, this type of injury seems to be caused by lack of exchange of materials with the environment leading to the accumulation of toxic metabolic products and/or the depletion of important cell metabolites such as ATP resulting in cell starvation and, eventually, death.

Example:- Salmonella Sp.

How does Freezing cause cell injury and death?Cells injury death caused by freezing depends on the cooling rate as follows:

Slow freezing. When cooling is slow (freezing rates that occurs in domestic freezers) ice crystals from outside the

cell. This causes an increase in the concentration of solute in the environment outside the cell followed by plasmolysis, cell shrinkage and eventually death. There is no evidence hat any mechanical damage is associated with the formation of ice crystals outside the cell. This type of freezing damage is the most lethal. Fast freezing:-

When cooling is fast (freezing rates used in the food industry) ice crystals form inside cells. The mechanism by which fast freezing causes damage is not well understood but possibilities are:1. Mechanical damage to cell membranes and DND molecules cause by ice crystals;2. An increase in the concentration of internal cell solutes leading to pH changes and an increase in ionic strength which in turn

damage cell protein and nucleic acids;3. Formation of gas bubbles during thawing which cause mechanical damage to cell membranes. Ultra fast freezing:-

When cooling is ultra fast (freezing rate produced by plunging cells into liquid nitrogen at –196’C) water freezes to form a glass-like substance and the formation of damaging intracellular ice crystals is reduced. Cell damage is minimized and most of the injury to cells appears to be associated with thawing rather than the freezing process.

WHAT HAPPENS TO INJURED CELLS AFTER THAWING?Cells that are injured but not killed can recover after thawing as long as there is an ample supply of nutrients (damaged

organisms often have growth factor requirements that are not normally evident) and the environment does not contain inhibitors. Injured cells will recover quite readily in thawed foods. Cells of food poisoning organisms that are injured rather than killed

2. RELATIVE HUMIDITY OF ENVIRONMENT : The Rh of the storage environment is important both from the aw within foods & the growth of microorganisms at the

surfaces. When the aw of a food is set at 0.60, it is important that this food be stored under conditions of Rh that do not allow the food to pick up moisture from the air & thereby increase its own surface & subsurface aw to a point where microbial growth can occur. When foods with low aw values are placed in environments of high Rh the foods pick up moisture until equilibrium has been established.

Likewise, foods with a high aw lose moisture when placed in an environment of low Rh. There is a relationship between Rh & temperature that should be borne in mind in selecting proper storage of foods. In general, the higher the temperature is, the lower is the Rh & viceversa.

Foods that undergo surface spoilage from moulds, yeasts & certain bacteria should be stored under conditions of low Rh. Improperly wrapped meats such as whole chickens & beef cuts tend to suffer surface in the refrigerator much before deep spoilage occurs, due to the generally high Rh of the refrigerator & the fact that the meat spoilage flora is essentially aerobic in nature, the changes of surface spoilage in certain foods by storing under low conditions of Rh, it should be remembered that the food itself will lose moisture to the atmosphere under such conditions & thereby become undesirable.

In selecting the proper environmental conditions of Rh, consideration must be given to both the possibility of surface growth & the desirable quality to be maintained in the foods. By altering the gaseous atmosphere, it is possible to retard surface spoilage without lowering Rh.

3. PRESENCE AND CONCENTRATION OF GASES IN THE ENVIRONMENT : The storage of food in atmosphere containing increased amounts of CO2 upto about 10% is referred to as controlled

atmosphere [CA] or modified atmosphere [NA] storage. Usage of this is employed in many countries with apples & pears. The concentration of CO2 generally does not exceed 10% & is applied either from mechanical sources or by use of dry ice (solid CO2).

CO2 has been shown to retard fungal rotting of fruits caused by a large variety of fungi. The mechanism is unknown, but it acts as a competitive inhibitor of ethylene action.

Ethylene seems to act as a senescence factor in fruits, and its inhibition would have the effect of maintaining a fruit in a better state of natural resistance to fungal invasion.

Ozone added to food storage environments has a preservative effect on certain foods. At levels of several parts per million, this has been tried with several foods and found to be effective against spoilage

microorganisms. It is a strong oxidizing agent; it should not be used on high lipid content foods, since it would cause an increase in

rancidity. Both CO2 ozone are effective in retarding the surface spoilage of beef quarters under long term storage.

5.Explain about contamination and spoilage of vegetables and fruits.

Introduction: Spoiled food may be defined as food that has been damaged or injured so as to make it undesirable for human use. Food spoilage may be caused by insect damage, physical injury of various kinds such as bruising and freezing, enzyme

activity, or microorganisms. It was estimated that 20 % of all fruits and vegetables harvested for human consumption are lost through microbial

spoilage by one or more of 250-market diseases. Vegetables and fruits are fresh, dry, frozen, fermented, pasteurized or canned.

Contamination:1. During harvesting => boxes, lugs, baskets, trucks, containers.2. Soil3. During transportation.4. Mechanical damage => processing / trimming5. Washing preliminary soaking distribute spoilage organisms.

a. Re-circulated or reused water may add micro organisms (washing with detergent/ germicidal solution reduce number of micro organisms).

Storage containers / bins Handling Spray water and ice growth of psychographs Equipment tables, blanches, press, filters, cloth, wooden surface.

General microbiological profile of harvested fruits and vegetables:Vegetables: Fruits:

Some

microorganisms involved in the spoilage of fresh vegetables.

Bacteria Microorganisms Vegetables SymptomCorynebacterium sepedonicum Potato Ring rot of tuberPseudomonas solanaceanum Potato Soft rotErwinia carotovoraVar.atroseptica

Potato Soft rot

Streptomyces scabies Potato ScabXanthomonas campestris Brassicas Black rotFungi Botrytis cinerea Many Grey mouldBotrytis allii Onions Neck rotMycocentrospora acerina Carrots Liquorice rotTrichothecium roseum Tomato

CucurbitsPink rot

Fusarium coeruleum Potato Dry rotAspergillus alliaceus Onion

GarlicBlack rot

Preservation of vegetables:1. Asepsis sanitization of equipments.2. Removal of microbes washing chlorinated water, lye solution, and detergents.3. Blanching / trimming / blanching washing with hot water at 90-100c, inactivate food enzymes and surface

sterilization).4. Heat canning5. Chilling cold water i.e., refrigerator, vaccum cooling

Hydro cooling cold H2O spray Controlled atmosphere Co2 / ozone. Eg potatoes 2.2 to 4.4 c

6. Freezing survival of Micrococus, Achromobacter, Enterobacter, spores of Clostridium and Bacillus.

Molds BacteriaFusarium, Alternaria, Aureobasidium, Penicillium, Sclerotinia, Botrytis, Rhizopus

Pseudomonas, Alcaligenes Erwinia AnthomonasMicrococci BacillusLactic acid bacteria Corynebacterium.

Molds BacteriaCladosporium Phoma TrichodermaAnd above organisms.

Pseudomonas, Alcaligenes Erwinia AnthomonasMicrococci BacillusLactic acid bacteria Corynebacterium

7. Drying explosive puffingSmall pieces of diced partially dehydrated vegetables are placed in a closed rotating chamber.

Heat applied, chamber is pressurized to a pre-determined level

Pressure is released instantaneously

Results internal loss of water

Increased porosity simplifies further drying8. Preservative rutabagas and turpips are parafinned.

o Lettuce, beets, spinach => ZnCo3 (to prevent mold).o Controls Fusarium on potato => biphenyl vapours, Co2 and ozone used.o Saueskraut / cauliflower / lemon => Nacl (2.25 to 2.5%)

High protein vegetable => Nacl (18.6 to 21.2%)o Brine solutiono Salad freshers => sulfiteso Sugars

9. Irradiation gamma radiation (insect) – potato, onion, garlic.Preservation of fruits:

1. Asepsis2. Removal of microbes => trimming3. Use of heat => blanching, canning=> fruit juices

Low PH food => tomatoes, pears, pineapple.High PH food => berries

4. Use of low TChilling => before chilling – propionate, borax, NaHCo3, biphenyl phenols, orthophenyl phenols, hypochloride, So2, thiourea, thiobendazole, dibromotetra chloroethane added to avoid shrinking and surface sterilization occurs.

5. Controlled atmosphere =>increases Co2 and decrease O2 content (Co2 storage) to prevent molds).6. Modified atmosphere => 100% N2 (N2 gas storage).

Co2 storage apples, citrus, grapes, pears, plums,banana peaches Ozone 2-3 ppm (strawberries, grapes, raspberries) Ethylene ripening (color Changes)

7. Freezing, drying dehydration, sulfuring, blanching8. Preservative Na, o- phenyl, phenates, waxes, hypochlorites, biphenyl alkaline Wrapper I2, S, biphenyl, O – phenyl phenol + hexamine, ozone, So2.

Spoilage:S.no Kinds of spoilage Organism involved

1 Bacterial soft rot(Soft, mushy bad odour)

Erwinia carotovora, Ps.marginatus, clostridium sp, Bacillus sp.

2 Gray mold Botrytis cinera (gray mycelium)3 Rhizopus soft rot R.stolonifer (Soft mushy black dot sporangia)4 Anthracnose spots of leaves Collectotfichum lindemuthianum C.coccodes5 Aiternaria rots Alternaria tenuis (greenish – brown / black spots)6 Blue mold rot Penicillium digitatum (bluish green rot)7 Downy mildew Phytophthora, Bremia (white woody masses)8 Watery soft rot Sclerotinia sclerotium (vegetable)9 Stem end rot Diplodia, atternaria, Fusarium

10 Black mold rot Asp,niger (Dark brown – black smut)11 Black rot Alternaria12 Pink mold rot Trichothecium roseum13 Fusarium rot Fusarium14 Green mold rot Cladosporium sp,Trichoderma sp15 Brown rot Sclerotinia sp16 Sliminess / souring Saprophytic bacteria in piled, wet, heating vegetables

Fungal spoilage of vegetables often results in water soaked, mushy areas, while fungal rots of fleshy fruits such as apples, peaches frequently show brown or cream colored areas in which mold mycelia are growing in the tissue below the skin and aerial hyphae and spores may appear.

Some types of fungal spoilage appear as dry rots, where the infected area is dry and hard and often discolored. Rots of juicy fruits may result in leakage.

Molds are favoured due to deficiency in vitamin B. Spoilage may be by;

Damage by mechanical means, plant pathogens or bad handling will favors entrance. Direct contact with moist soil – roots, tubers or bulbs. eg carrots, beets, radishes, potatoes Direct contact with surface soil. Eg: strawberries, cucumbers, and peppers.

Spoilage of fruit and vegetable juices:1. Molds can grow on the surface of juices due to high moisture content, acidity, low in sugar.2. The removal of solids from the juices by extraction and sieving raises the oxidation – reduction potential and favors the growth of yeasts.3. Most fruit juices are acid enough and have sufficient sugar to favors the growth of yeasts.4.Deficiency of vitamin B discourages some bacteria.

Yeast / acetic acid5. Fruit juice Alcohol acetic acid

Mold bacteria Lactic acid bacteria

Lactic acid6. Fruit juices undergo changes like;a. LA fermentation of sugars L.pastorianus

L.brevis Leuonostoc mensenteroides (apple or pear juice) Lactobacillus rabinosus L.leichmanii Microbacterium

b. Fermentation of organic acids of juice by LA bacteriai.e, malic acid lactic and succinic acidsquinic acid dehydroshikimic acidsCitric acid lactic and acetic acidsc. Slime production by L.mesenteroides, L.brevis and L.plantarum in apple juice and L.plantarum and streptococci in grape juice.7. Vegetable juices also contain a plentiful supply of accessory growth factors for microorganisms and hence support the good growth of fastidious lactic acid bacteria.8. Acid fermentation of raw vegetable juice by these and other acid forming bacteria causes yeasts and molds to growth.

6.Explain about contamination and spoilage of eggs (poultry products)spoilage

INTRODUCTION The hen’s egg is an excellent example of a product that normally is well protected by its intrinsic parameters. Externally, a fresh egg has three structure, each of which is effective to some degree in retarding the entry of

microorganismsI. The outer, waxy shell membrane

II. The shell III. The inner shell membrane.

Internally, lysozyme is present in egg white effective against gram-positive bacteria. CONTAMINATION:

1. Faecal.2. Soil3. Cage => shell => gram positive organisms, Salmonella, Streptococcus, Staphylococcus, Micrococcus, Sarcina,

Bacillus, Alcaligenes, Flavobacterium, Proteus, Serratia, Aeromonas, molds, like Penicillium, Mucor.PRESERVATION:

Eggs have some protective barrier;a. Shell => cuticle / bloom (layer on shell, polished) if cuticle is removed then organism enters.b. Shell membrane.c. Albumin content => anti Proteolysis factor

PH 9 to 13 has lyzozyme Any organism cannot survive It is less dense If org entered yolk means organism survive.

1. Asepsis => equipment sanitize, handling must be care and prevent contamination.2. Removal of microbes => dry cleaning by sandblasting (washing with hot water)=> removes bloom so not advisable.

* Mechanical egg washer;1 % hypochlorite => to sanitize equipment.

2% acetic acid => very effective but reduce the size of shell => don’t store, use immediately as bloom removal.3. Use of heat => heating in water but avoid coagulation

i.e, 57.5 C => 800 sec 60 C => 320 sec

Heating in oil => 60c for 1 min 54.4 C for 30 min

Immersion in hot detergent sanitizer 43.3 to 54.4 c Thermo stabilization => slight coagulation of albumin. Pasteurization => before this add Aluminium and salt to adjust PH

4. Use of low T chilling -1.7 to –0.55c with air circulation.Rh is 70 to 8 (6 months)

For this eggs are selected by candlingThis removes

a. Increased air sacb. Infected eggsc. Rotten eggs

Avoid moisture on the shell Impregnation of eggshell with colorless, odorless, oil improves their quality.

Freezing Rinse 200-500 ppm of Cl2 / I2

Frozen in 30- or –50lb tin can/ container Add 5% sugar / salt/ glycerol before freezing T –17.8 to –20.5 C

Drying Removal of glucose prevent browning / maillard rxn Removal of glucose may be by 1. Fermentation using Group.D stretococci, Enterobacter aerogenes or Saccharomyces sp. 2. Using the enzyme glucose oxidase at 10cDryers used areSpray dryer, Drum, Rotor, air, pan and tunnel dryer (60-71C) Final moisture content => 5 to 1% was retained Before drying pasteurization was carried out After drying some organisms can act as contaminants from handlers, equipment or through air and soil. They

are Micrococci, str. facealis, coliforms, Salmonella, spore formers and molds.6. Use of preservative waxing, oiling prevent O2 entry and maintain dry shell.a. Materials used for dry packaging of eggs are salt, lime, and saw dust, sand and ashes.b. Solution of sodium silicate for dipping.c. Others => borates, permanganates, benzoates, salicylates, formats.d. Washing of eggs with hot solution of germicides;

1. Hypo chlorites2. Ly solution3. Acids4. Formalin5. Quaternary ammonium compounds6. Sealing of shells solution of dimethylourea inhibits mold growth.7. Mycostatic sodium pentachlorophenate8. Fumigation gaseous ethylene oxide9. Co2 + ozone (CA) 0.6 pp for clean eggs

1.5 ppm for dirty eggs10. N2 storage.11. – 0.55 C to 90% Rh keeps eggs fresh for 8 months12. Radiation rays is used to prevent salmonella.

Spoilage:1. General appearance.2. Candling with transmitted light.3. Broken egg

These are obvious for spoilage.Defects in fresh egg:

Fresh eggs may have cracks, leaks, loss of bloom or glass, stained or dirty spots on exterior as well as meat spots (blood clots), general bloodiness, or translucent spots in the yolk when candled. From among these, any breaks in the shell or dirt on the egg will favors spoilage on storage.Changes during storage:

1. Microbial.2. Non – microbial

1. Changes due to non- microbial agents:1. Egg breakage.2. Storage of old eggs results in protein denaturation.3. Air sac increased.

2. Changes due to microbes:Bacteria:1 Green rots Pseudomonas. fluorescens

Bright green colour, fruity / Swedish odour, not detected by candling.2 Colorless rots Pseudomonas, Acinetobacter, Alcaligenes, coliforms.

Identified by candling, odour, white incurstation3 Black rots Proteus, Pseudomonas, Aeromonas, Pr.melanovegenes

Odour – H2S, putrid – muddy brown.4 Pink rots Pseudomonas

Pinkish ppt of yolk5 Red rots Serratia

Mild odour6 Others Enterobacter, alcaligenes, Escherichia, Flavobacterium, Paracolobacterium

Fungi:1. Pin spot molding:

1. Penicillium yellow / blue / green spot2. Cladosporium dark green / black spot3. Sporotrichum pink spot

2. Superficial fungal spoilage:*Fuzz / whiskers on shell during storage increase RH and no air circulation.Fungal rotten Penicillium, Cladosporium, Sporotrichum, Mucor, Thaminidium, Botrytis, Alternaria.3. Fungal red rot Sporotrichum4. Black rot Cladosporium Achromobacter peolensPseudomonas. graveolenOff flavour / musty odour Pseudomonas. mucidolensBad odour (hay flavour) Enterobacter cloacae (due to faecal contamination)Cabbage water flavour (fishy flavour) E.coli (due to faecal contamination).

7.Explain about contamination and spoilage of meat and meat product.Introduction

Meat are the most perishable of the important foods, in which the chemical composition of a typical adult mammalian muscle postmortem is presented.

Meat contain an abundance of all nutrient required for the growth of bacteria, yeasts,and molds, and an adequate quantity of these constituents exist in fresh meats in available form.

When spoiled meat products are examined, only a few of the many genera of bacteria, molds ,or yeasts are found.

Almost all cases one or more genera are found to be characteristic of the spoilage of a given type of meat product.

Frequently isolated microorganisms from meatS. no Product Microorganisms isolated 1 Fresh and refrigerated meat Bacteria

Acinetobacetr,Moraxella

PseudomonasAeromonasAlcaligenesMicrococcus

Molds CladosporiumGeotrichum

SporotrichumMucor

ThamnidiumYeasts

CandidaTorulopsis

DebaryomycesRhodotorula

2 Processed meat and cured meats BacteriaLactobacillus and other lactic acid bacteria.

AcinetobacterBacillus

MicrococcusSerratia

StaphylococcusMolds

AspergillusPencilliumRhizopus

ThamnidiumYeast Debaryomyces,TorulaTorulopsis,Trichosporoncandida

Contamination:1. Lymph node (more number of micro organisms) staphylococcus, streptococcus, clostridium, salmonella2. Flesh => good culture media as it contains protein, carbohydrate, lipids and vitamins.3. Bleeding, handling, processing (enter – full circulation in body). Skimming, cutting, knife.4. Hide, hooves, hair5. Soil, H2o, feed, manure, air, wood (slaughter house)6. Intestinal organism coli forms, pathogenic fungi7. Container, boxes8. Meat surface – molds => Cladosporium, Sporotrichum, Geotrichum, Thamnidium, Mucour, Penicillium.9. Pseudomonas, Acinetobacter, Moraxella, Alcaligenes, Micro cocci, Flavobacterium, Proteus

utensil contamination and salt tolerant Found in meet products.

Characteristics of some Gram negatives associated with meat.Gram negative

Not fermentative in OF medium

Oxidase +ve Oxidase –ve

Motile non motile non motile

Pseudomonas Acinetobacter(formerly Moraxella) (Achromobacter)Psychrobacter (formerly Moraxella-like)

Polar flagella

Not oxidase Oxidase in OF medium in OF mediumPseudomonas PseudomonasShewanella (Achromobacter(Alteromonas)Preservation:1. Asepsis:

Sanitation and H2o spray (before cutting) (utensils) After cutting => hot H2O / detergents etc

2. Use of heat:

Canning

1. Commercially sterile (Self stable)=> 90C (11 lbs)Process by increasing heat + Nacl / salt solution

2. Non self stable => stable for some pots (controlled atm) => heat process (65C with 22 lbs) – canning => refrigeration.

3. Use of low T: Chilling:

o -1.4 to –2.2Co Particularly maintained or else spoilage => beef => 30 dayso Pork, lamb, mutton => 1-2 weekso Real (calf meat) => shorter periodo (CA) + Addition of Co2 + ozone => increase Co2 / ozone leads to formation of metmyoglobin, from

myoglobin change the colour.o Co2 10 to 30% for most meet

100% for bacon.o ozone => 2.5 to 3 ppm (92% Rh) => 60 days maintainedo Chilling T => Pseudomonas, Acinetobacter, Moraxiella, Alcaligenes, Pediococcus cerevisiae, (salt tolerant)

=> does not effect in curing. Freezing:

-1.22 to –28.9 C (Pseudomonas, Moraxiella, Acinetobacter, Alcaligenes, Micrococcus, Lactobacillus, Flavobacterium, Proteus).

4. Use of radiation:i. UV [air] surface of meat products

ii. rays Depend meat products [Hard Meat – Increase rays]iii. Increase rays – Porkiv. 20 – 70 K-Grays – Normal

5. Drying: Slice & Dried Sodium nitrites – to dry the surface of meat

6. Freeze drying: Meat Products generally are not freeze Bleeding – removal of liquid to outside Freeze burn – Change in colour – brown colour Smoking

7. Curing: Addition of Salt NaCl – 15% salt (immerse meat)

o 24% salt [inject to meat) Preservating & flavouring agent

o NaNo3 Colour Fixative [bright red] & bacteriostatic Increased concentration lead to brown colour Sugar – adds flavour and serves as an energy source for nitrate – reducing bacteria

4 Methods of introduction of curing agents into meat;1. Dry2. Pickle3. Injection4. Direct-Addition

Spoilage of Meat: Oxidation occurs Due to protease, lipases

Factors that influence the invasion of Microbes: Load in the gut Physiological condition of animal Method of killing & bleeding Rate of cooling

Aerobic condition influences the growth of bacteria, molds, yeast.Factors that influence the growth of Microbes in Meat:

Kinds of no. of microbes Physical properties of meat Chemical properties of meat RH, PH [5.7 to 7.4 based on glycogen], chemical composition of meat. Availability of O2. Temperature

Animal pathogen Salmonella, Camphylobacter, Pseudomonas.

Spoilage under Aerobic Conditions:1. Surface Slime: Pseudomonas, Acinetobacter, Alcaligenes, Moraxella, Streptococcus, Leuconostoc, Bacillus, Micrococcus, Lactobacillus.2. Discolouration of Meat Pigment:

Autolysis also occur Generally meat has heamoglobin; myoglobin due to oxidation produces metmyoglobin.

MeatHb, Myoglobin Oxidation Metmyoglobin[Purplish Pink] [Brown]

Blooms i.e., Red Green / Brown / Grey Oxidizing compounds peroxidase, H2S results in spoilage. Organisms involved may be Lactobacillus sp., Leuconostoc sp and other heterofermentative organism

3. Changes in Fat: Oxidation of unsaturated fats catalyzed by light & copper Lipolytic organisms Pseudomonas, Achromobacter yeast Oxidative rancidity (degradation of fat) results in tallowy odour

4. Phosphorescence: Luminous bacteria Photobacterium on the surface of meat

5. Discolouration of meat due to Bacterial Pigment:Red spot Serratia marcesensYellow Micrococcus, Flavobacterium, Chromobacter lividiumGreenish / Blue / Brownish Black Proteus & others

6. Taint [Off flavour and odour]: By yeast, Actinomycetes results in musty / earthy flavour Yeasts produce acetate, formate, butyrate & propionate.

Aerobic Growth of Molds:1. Stickness2. Whiskers Thamnidium Chaeotocladioides, T.elegans, Mucor, M.Mucida, M.raceonogus, Rhizopus.3. Black Spot Cladosporium herbarum4. White Spot Sporotrichum Carmi5. Green pathches P.expansum, P.oxalium, P.asperulum.6. Decomposition of Fat7. Taint Musty flavour Thaminidium taint by Thaminidium sp.

Spoilage under Anaerobic Conditions:1 Souring Due to formate, acetate, propionate, lactate, succinate and fatty acids.

By clostridium & other facultative anaerobes After protein / fat lysis in aerobic leads to anaerobic condition

2 . Putrefaction Anaerobic decomposition of protein leads to fowl smell and results in production of H2S, mercaptans, indole, skatole, NH3, amines

Caused by Clostridium and other facultative anaerobes3 Taint Bone Taint Souring / putrefaction next to bones

Spoilage of Different Kinds of Meat:Fresh Meat:1 Refrigeration Pseudomonas, Actinetobacter, Moraxiella2 Shine form LA bacteria3 Green discolouration Lactobacillus, Leuconostoc4 Souring Streptococcus, Pediococcus, BrevibacteriumFresh Beef:

1. Oxidation of mycoglobin & Hb.2. White, green, black, greenish blue, yellow, brown, black spots.3. Phosphorescence.4. Shine formn bacteria, yeast

5. 10 C Meat Pseudomonas6. Whisters & Stickiness

Hamburger:1 Putrefaction at RT2 Souring Near freezing3 Low Temperature Pseudomonas, Acinetobacter, Moraxella, Micrococcs, Flavobacterium, Alcaligenes4 High Temperature Bacillus, Clostridium, E.coli, Micrococcus, Sarcina, Mucor, Lactobacillus,

Leuconostoc, Penicillium, Alcaligenes, Streptococci, Enterobacter, Proteus, Pseudomonas

Fresh Pork Sausage:1 Souring 0 – 11 C

Lactobacillus,Micrococcus, Microbacterium2 Colour spot Molds3 Dark spot Alternaria [on refrigeration]Cured Meat:1 Cured meat Salted Meat [NaCl / NaNo3]2 Nitrite Anaerobic NaNo3 favours LA bacteria, G+ve orgs, yeasts, molds.Dried Beef / Beef Hams:1 Factor H2O, Rh2 Spongy Bacillus3 Sour LA bacteria4 . Red Halobacterium salinarium, Bacillus5 Blue Ps.syncyaneae, Penicillium spinulosum,

Rhodotorula.6 . Gas in jars Pseudomonas.fluorescens7 Co2 in jars Bacillus.

Sausage:Slime Moisture Micrococci & Yeasts

Decrease Fuzziness discolouration Molds Sour Leuconostoc , LactobacillusSwell package due to Co2 by heterfermentative LA bacteria.

Fading red colour to chalky grey BacteriaGreening of sausage Leuconostoc, LactobacillusProduction of Nitric oxide Nitrate reducing bacteria.Bacon:

Mold Aspergillus, Alternaria, Mucor, Rhizopus, PenicilliumHam:* Souring Alcaligenes, Bacillus, Pseudomonas, Lactobacillus, Proteus, Micrococci.* Putrefaction Odour – Mercaptans, H2S, Amines, Indole.

Refrigerated Packed Meat:* Due to packaging film & Co2 Pseudomonas, Acinetobacter, Moraxella* Off flavour, shine & putrefaction.8.Explain about contamination and spoilage of fish and seafood.Introduction

Both salt-water and fresh water fish contain comparatively high levels of proteins and other nitrogenous constituents. The carbohydrate content of these fish is nil. While fat content varies from very low to rather high value depending

upon species. Of particular importance in fresh flesh is the nature of the nitrogenous compounds. the relative percentage of total –N

and protein-N are presented from which it can be seen that not all nitrogenous compounds in fish are in the form of proteins.

Among the non-protein nitrogen compounds are the free aminoacids, volatile nitrogen bases such as ammonia and trimethylamine, creatine, taurine, the betaines, uric acid, anserine, carnosine, and histamine.

(CH3) 3 N OTrimethylamine oxide

TMO reductase (CH3) 3 NTrimethylamine

Contamination:1. Flora of fish depends on the waters in which they live.2. Slime that covers the outer surface of fish is Pseudomonas, Aeromonas, Acinetobacter, Moraxella, Alcaligenes,

Micrococcus, Flavobacterium, Corynebacterium, Sarcina, Serratia, Vibrio, and Bacillus.3. Northern Waters Psychrophiles

Tropical Waters MesophilesFresh Waters Aeromonas, Lactobacillus, Brevibacterium, Alcaligenes, Streptococcus.

4. Intestine of fish Alcaligenes, Pseudomonas, Flavobacterium, Vibrio, Bacillus, Clostridium, Escherichia.1. Boats, boxes, bins, fish houses & fishers become heavily contaminated with three bacteria & transfer them to fish

during clearing.2. Oysters, other shell fish Pick up organisms from soil & water

Alcaligenes, Flavabacterium, Moraxella, Acinetobacter, G+ve sp. 7. Shrimps, Crabs, Lobsters s Bacillus, Micrococcus, Pseudomonas, Acinetobacter, Moraxella, Flavobacterium, Alcaligenes, Proteus.Fish and fish products:

Cooked, frozen products

Frozen fish Vacuum packing

Dried fish Fresh fish Canned

Fermented fish Marinades

Cured,smoked fish

Spoilage:1. Autolysis2. Oxdn or bacterial activity

3.Combination of these. Fish flesh is perishable because of this rapid autolysis of fish enzymes and because of less acid r x n of fish flesh that

favours microbial growth. Unsaturated fish oils are susceptible to oxdn. Rigos mortis [stiffness of body after death] is hastened by struggling of the fish, lack of O2, warm T and is delayed by a

low pH and adequate cooling of the fish. Muscle glycogen low pH Lactic acid

BacteriaFactors influencing kind and rate of spoilage:1. Kind of Fish:

Flat fish spoil more rapidly than round fish. Flat fish;

i. PH 5.5 of its fleshii. Oxidation of unsaturated fats

In certain fishes high in trimethylamine oxide soon yield appreciable amounts, of stale-fishy trimethylamine.2. Condition of Fish when caught:

Feedy fish [full of food when caught, more perishable than those with an empty intestinal tract]. Fish that are exhausted result of struggling, lack of O2 excessive handling spoil more rapidly.

3. Kind and Extent of Contamination of Fish Flesh with Bacteria: Micro organisms may come from mud, H2O, handlers, exterior’s slime and intestinal content of fish and to enter gills and

pass through vascular system and invade the flesh and entry to body cavity. Greater the load of bacteria leads to easy spoilage of fish.

4. Temperature:Cooling 0 to –1 C5. Use of an Antibiotic Ice / Dip

Evidences of Spoilage:1. Fresh condition Staleness2. Colour of fish fade, dirty, yellow, brown discoloration3. Shine on skin increases flaps & grills.4. Eyes sink & shrink, pupil – Cloudy, Cornea – Opaque.5. Gills turn to a light pink to grayish –yellow colour.6. Softening Juice Extraction squeezed Identified by the finger.7. Reddish – brown discoloration towards the tail due to oxidation of Hemoglobin.8. By odors.

Normal, fresh, seaweedy odor Sticky sweet

Stale fishy (trimethylamine)

Ammoniacal

Final putrid (H2S) (Indole & other malodorous compounds)9. Fatty fishy & rancid odors.Bacterial Spoilage:

1. Pseudomonas, Acinetobacter, Moraxella, Flavobacterium chilling.2. Higher Temperature Micrococcus, Bacillus.3. atmospheric temperature Escherichia, Proteus, Serratia, Sarcina, Clostridium.4. Bacteria on Surface Penetrate the flesh

N2 and glucose favour growth

[putrescine, cadaverine], lower fatty acids, CHO, H2 and other Sulfides, mercaptans, indole.

Indicative of putrefaction

5. Musty odor / Muddy odor & taste StreptomycesDiscolouration:

6. Yellow to greenish yellow colours Ps.fluorescens7. Yellow Micrococci8. Red / Pink colours Sarcina, Micrococcus, Bacillus, Yeasts & molds. 9. Chocolate brown colour Asporogenous yeast.

Spoilage of Special kinds of Fish & Sea Foods:1. Salt fish

2. Smoked fish

3. Marinated (sour pickled) fish

4. Japanese fish sausage

5. Shell fish

6. Chilled shrimp

7. Crab meat

8. Ran lobsters

9. Crabs and oysters

Salt tolerant / halophilic bacteria of Serratia, Micrococcus, Bacillus, Alcaligenes, Pseudo.

Molds

Molds (if acidity increases growth favours)

Souring by volatile acid production by Bacilli or to putrefaction

As on fish spoilage

Acinetobacter, Moraxella, Vibrio, Increases in Pseudo, increases Flavobacterium, Micrococcus, Bacillus

Chilling Pseudo, Acinetobacter, MoraxellaHigh T Proteus

Pseu, Alcaligenes, Flavobacterium, Bacillus

Vibrio, V.parachemolyticus

Oysters

Kept alive in shell at chilling Temperature. Decompose rapidly when they are dead Not only rich in protein but also in sugars Near freezing spoilage occurs by Pseudomonas,Acinetobacter, Moraxella, Flavobacterium,

Micrococcus. Spoilage called as sourcing (Proteolytic) At high Temperature souring may be result of Fermentation of sugars by coliforms, Streptococcus, Lactobacillus, yeast to produce acids and a

sour odor.o Pink oysters Asporogenous yeasto Others are Pseu, Serratia, Proteus, Clostridium growth occurs.

9.Explain about preservation of food using high temperatue.principles of food preservation

1.Prevention or delay of microbial decomposition:a) By keeping out microorganisms (asepsis).b) By removal of microorganisms (filtration).c) By hindering the growth and activity of microorganisms.

Eg; by low temperature, drying, anaerobic conditions, chemicals.d) By killing the microorganisms.

Eg; by heat or radiation.2. Prevention or delay of self-decomposition of food:

a. By destruction or inactivation of food enzyme. Eg; blanching.b. By prevention or delay of purely chemical reactions. Eg; prevention of oxidation by means of an antioxidant.

3.Prevention of damage because of insects, animals, mechanical causes etc.,METHODS OF PRESERVATION:

1) Asepsis2) Removal of microorganisms.3) Maintenance of anaerobic conditions eg: in a sealed, evacuated container.4) Use of high temperature.5) Use of low temperature.6) Drying.7) Use of chemical preservative.8) Irradiation.9) Mechanical destruction of microorganisms grinding, high pressure.

ASEPSIS:1) It refers Combination of two or more of the above methods.2) to keeping out of microorganisms.3) Inner tissues of healthy plants and animals are free of microorganisms, if they are present leads to initiate the spoilage.4) If there is protective covering the spoilage may be delayed or prevented. Eg; shells of nuts, skins of fruits and vegetables,

husks of ear corn, shells of egg, skin or membranes or fat on meat or fish.5) The food technologists are concerned with bioburden of microorganisms where they consider both kinds and numbers of

microorganisms in food.6) Packaging of foods is a widely used application of asepsis. Eg; loose carton or wrapping.7) Dairy industry concentration is made during milking process, handling.8) Canning industry sealing can prevent contamination.9) Meat packaging industry sanitary methods of slaughter, handling and processing reduce the load and thus improve the

keeping quality of meat or meat products. Intestinal flora must be removed in animals.REMOVAL OF MICROORGANISMS:

Removal of microorganisms may be by;1) FILTRATION:

The liquid is filtered through a previously sterilized bacterioproof filter made of sintered glass,Diatomaceous earth, unglazed porcelain, membrane pads or similar material and the liquid is forced through by positive or negative pressure. Eg; fruit juices, beer, soft drinks, wine and water. 2) CENTRIFUGATION: (SEDIMENTATION)

It is not very effective. Sedimentation is used in the treatment of drinking water. When centrifugation (clarification) is applied to milk, the main purpose is not to remove bacteria but to take out other suspended materials, although centrifugation at high speeds removes most of the spores.

3) WASHING:It can act as surface sterilization. Eg; removal of soil microorganisms on the surface is by washing in fruits,

vegetables, (cabbage, cucumber) etc. Washing foods may be dangerous if the water adds spoilage organisms or increases the moisture so that the growth of spoilage organisms is encouraged.

1) TRIMMING:Removal of the spoiled particles of a food or discarding spoiled samples is important. Eg; Trimming the outer

leaves of cabbage heads is recommended for the manufacture of sauerkraut.MAINTENANCE OF ANAEROBIC CONDITIONS:

Sealed packaged foods involve anaerobic conditions. Canned foods headspace is filled by carbon dioxide or nitrogen where maintains anaerobic conditions. Anaerobic conditions prevent the growth of aerobes, aerobic spore formers.

PRESERVATION BY USE OF HIGH TEMPERATURE:The killing of microorganism by heat is due to;

1. denaturation of proteins.2. inactivation of enzymes.3. control of metabolism.

FACTORS AFFECTING HEAT RESISTANCE:1.TEMPERATURE-TIME RELATIONSHIP:Time for killing cells or spores under a given set of conditions decreases as the temperature is increased.

EFFECT OF TEMPERATURE OF HEATING ON TIME NEEDED TO KILLSPORES OF FLAT SOUR BACTERIA:TEMPERATURES TDT IN MINUTES100105110115120125130135

12006001607019070301

2. INITIAL CONCENTRATION OF SPORES OR CELLS:If spores and cells are in greater amount then there is need of increased heat treatment to kill them.

EFFECT OF INITIAL NUMBERS OF SPORES ON TIME REQUIRED TO KILL THEM:

INITIAL CONCENTRATION OF SPORES (NO./ML)

TDT MIN. AT 1200C

5000500050050

14100908

3.PREVIOUS HISTORY OF THE CELLS OR SPORES:A) CULTURE MEDIUM: Spores are more resistant in soil than medium. Glucose increases the heat resistance. If there is increased sugar concentration, in turn acid production is increased results in decreased heat resistance. Phosphate and magnesium said to decrease the resistance of bacterial spores.

B) TEMPERATURE OF INCUBATION:As the temperature increases the resistance also increases. Eg; optimum temperature- highly resistant.

Minimum/Maximum temperature – highly sensitive.C) PHASE OF GROWTH/AGE:

Log phase decreased heat resistant. Lag and stationary phase increased heat resistant. Immature spores less resistant than mature ones. First week of storage (some spores) increase in resistant but later decrease in resistant. Dry spores harder to kill than moist spores.

4. CONCENTRATION OF SUBSTRATE:A) MOISTURE CONTENT:

If moisture content is increases it is easy to sterilize while the dried food requires increased temperature.Eg: spores of Bacillus subtilis in steam 10 min at 1200c, in glycerol 1700c for 30 min.B) pH: Neutral pH heat resistant (optimum) Acid/alkali pH heat sensitive (min/max) Cameron classified the foods into;Low acid foods pH (above 5.3),eg; ear ,corns, meat, fish, poultry, milk. Heat resistant.Medium acid foods pH (between 5.3 and 4.5). Eg; spinach, beets, pumpkin.Acid foods pH (between 4.5 and 3.7). Eg; tomatoes,pears,pineapple.High acid foods pH (3.7 and below). Eg; berries,sauerkraut. Heat sensitive.C) SUGARS/SALTS:

Due to increased concentration they can be easily destroyed. Antiseptic or germicidal substances in the substrate aid heat in the destruction of organisms. H2O2 + heat is used to reduce the bacterial content and is the basis of a process of milk.

HEAT RESISTANCE OF MICROORGANISM AND THEIR SPORES:THERMAL DEATH TIME:

It is defined as the time it takes at a certain temperature to kill a stated number of organisms under specified conditions. It is also referred to as the absolute thermal death time to distinguish it from the majority thermal death time for killing most of the cells or spores present.THERMAL DEATH TIME:

Expressed as the rate of killing.THERMAL DEATH POINT:

It is the temperature necessary to kill the entire organism in 10 minutes.1. HEAT RESISTANCE OF YEASTS AND YEAST SPORES:

The resistance of yeasts and their spores to moist heat varies with the species and even the strain, with the substrate in which they are heated.

1. Vegetative cell of ascospores 5 – 100c for destruction.2. Spores of yeasts 600c for 10 –15 min but few are resistant.3. No survival 1000c4. Vegetative yeasts 50 –580c for 10 – 15 min.5. Yeasts in bread (interior) 970c

2.. HEAT RESISTANCE OF MOLD AND MOLD SPORES: Most molds and their spores are killed by;

1. Moist heat 600c in 5 – 10 min.2. Asexual spore are more resistant than ordinary mycelia ( 600c) ie.,5 – 100c rise.3. Aspergillus, Mucor, Penicillium are more resistant to heat.4. Pasteurization kills spores and vegetative cells.5. Sclerotia are difficult to kill by heat and they can survive at 90- 100 0c to spoil canned fruits. They can be killed at 1000

min at 830c or 300 min at 850c.6. Mold spores are resistant to dry heat.

3.HEAT RESISTANCE OF BACTERIA AND BACTERIAL SPORES:1. Cocci are more resistant than rods.2. Higher the optimal and maximal temperature of growth, greater the resistance to heat.3. Capsule is difficult to kill.4. Cells high in lipid content are harder to kill.

ORGANISM T0 WITH TIMEBacillus anthracisB.subtilisCl.botulinumCl.calidotoleranceN.gonorrhoeaSalmonella typhi

1000c for 1.7 min1000c for 15-20 min1000c for 100 – 330 min1000c for 520 min500c for 2- 3 min600c for 4.3 min

4.HEAT RESISTANCE OF ENZYMES:1. Enzymes are inactivated at 79.40c for 10 min.2. Pasteurization of milk can be checked by the presence of bovine phosphatase. If this enzyme is

observed then the process was not carried out properly is understood.10.write a short notes on heat pentration in food substance.

Heat penetration:

The rate of penetration of heat into a food must be known in order to calculate the thermal process necessary for its preservation. Every part of the food in a can must have to obtain the adequate heat treatments to prevent spoilage may be by

1. Conduction – near the center (slow in food, rapid in metals)

2. Convection – heat passes from molecules to molecule.

When solid particles of food are suspended in a liquid, the particles heat by conduction and liquid heats by convection.

Factors involved are:

1. The material of which the container is made.

2. The size and shape of the container.

3. Initial temperature of the food.

4. Retort temperature.

5. Consistency of can contents and size and shape of pieces.

a. Pieces that retain their identity.

b. Pieces that cook apart and become mushy or viscous.

c. Pieces that layer.

6. Rotation and agitation.

Methods involved:

a. Below 100C

b. At 100 C

c. Above 100 C

Pasteurization:

Pasteurization is a heat treatment that kills part but not all of the microorganisms present and usually involves the application of temperature below 100C.1. When more vigorous heat treatments might harm the quality of the product. E.g.: market milk.

2. To kill pathogens. E.g. market milk.

3. Main spoilage organisms are not very heat resistant.

E.g.: yeast in fruit juices.

4. When process requires additional chilling.

5. When competing organisms are to be killed, allowing desired fermentations, usually by added starter organisms. E.g.: cheese making.

Preservative methods used to supplement pasteurization include;

1. Refrigeration.

2. Asepsis.

3. Maintenance of anaerobic conditions.

4. Addition of high concentration of sugar. E.g.: sweet condensed milk.

5. Addition of chemical preservative. E.g.: Pickles

1.Pasteurization time and temperature:

1. Milk Low temperature / long time

LTH / [holding] 62.8C for 30 min

High temperature short time

[HTST] 71.7C for 15 sec

Ultra pasteurization 137.8 C for 2 sec

2. Ice cream mix LTH 71.7 C for 30 min

HTST 82.2 C for 16-20 sec

3. Grape wine 82 –85 C for 1 min

4. Fruit wine 62.8 C for 30 min

5. Beer 60 C for 15 min

6. Dried food 85 C for 30 –90 min

7. Bottled grade juice 76.6 C for 30 min

8. Bottled apple juice 60 C for 15 min

9. Bulk apple juice 85-87.8 C for 30-60 sec

10 Vinegar 65.6 C for 30 min

If pasteurization is not proper, then there is the presence of enzyme bovine phosphatase. Q fever may be transmitted by milk.

2. Heating at 100 C:

1. Boiling

2. Blanching:

It is process where fresh vegetables before freezing or drying involves heating at about 100 C.

3. Baking:

The internal temperature of break, cake or other bakery products approaches but never reaches 100 C as long as moisture is present.

4. Simmering:

Simmering is gentle boiling with the temperature about 100 C.

5. Roasting:

In meat, the internal temperature reaches only about 60 C in rare beef, up to 80C in well-done beef, 85 D in a pork roast.

6. Frying:

The outside of the food very hot, but the center ordinarily does not reach 100 C.

7. Cooking:

Cook implies a specific time and temperature for a thermal process.

8. Warming up:

A small increase in temperature up to heating to 100 C.

3.Heating above 100C:

Milk can be heated to temperatures up to 150C by use of steam infection or steam infusion followed by flash evaporation of the condensed steam and rapid cooling. This is referred to as UHT processes.Canning / appertization:

Canning is defined as the preservation of foods in sealed containers and usually implies heat treatment as the principal factor in the prevention of spoilage. Canning is the general term and is replaced by hermetically sealed containers. Nicolas appert has been called the “Father of canning”.

Cans:

1. Initially glass vessels are used.

2. Later metals, plastics are used.

3. Corks were also used.

4. Recently cans are made of tin.

5. Enamels are coated on to flat sheets of plate before the manufacturer of cans to prevent or slow discoloration or corrosion.

6. Aluminum parts are used for products that do not require high vacuums or high -T processing. E.g.: Beer, foreign fruits, cheese.

7. Plastic flexible pouches or bags are used or plastic laminated with foil are employed mostly for packaging frozen, dried or unprocessed foods. They are also used for foods that can be packaged hot, although steam – pressure sterilization of foods in pouches has been accomplished.

E.g.: Jams, dried food products.

8. Tin cans were first used by Peter Durand.

Food has sulphur and tin has Fe combine to form FeS. Standard enamel is used for cans for highly colored fruits and berries or for beets to prevent the fading of colour caused by tin plate. Enamels are coated with Zno, so that the white ZnSo4 is formed instead of dark FeS, When low acid, sulfur – bearing foods such as corn as canned and darkening of the interior of the can be avoided.

Meat, fat-containing foods should not be stored in cans containing Zno as they split the fats. Special enamels may be employed for certain products. E.g.: milk, meat, wine, beer, soups and some fruit juices.

Food => Remove the spoiled food by trimming => wash with sterile water (Surface sterilization)

Blanching / steam sterilization and cooling

Blanching sets the colour, softens the tissues and kills some microbes

Add sugar / salt solution

Evacuated before sealing

Usually by heating headspace / unfilled part of the container by mechanical means.

Canned food (commercially sterile or practically sterile or bacterially inactive)

Other methods:

1. HTST

2. HC7 / Heat cool fill method.

3. Steam pressure E.g. Tomato juice may be presterilised at 121 C to 132 C to kill spores of B. coagulants before canning and then the sealed cans of juice are given a milder heating.

4. SC / Sterilizing and closing.

5. PFC / Pressure filler cooker.

6. Dehydrocanning.

E.g.: apple slices, food is dried to about half its original weight before canning.

7. Direct gas flame.

8. Steam injection.

9. Flash 18

10. Addition of preservation / irradiation / chemicals.

Pressurized packaged foods / aerosols:

They are packed under pressure of a propellant gas, usually

1. Co2 => inhibits many microbes => aerobic bacteria and molds not lactic acid bacteria. E.g. B. coagulans, Strep. facelis or yeasts.

2. N2 => inhibit anaerobes not aerobes.

3. Nitrous oxide = represses fungi.

E.g.: whipped cream, beverage toppings, salad dressings, oils, and jellies.

Cooling process:

The cans may be cooled by

1. Immersion in cold water.

2. Spray of water.

3. Large cans are cooled slowly to avoid strain or breakage.

4. By means of air currents.

Canning in the home:

1. Boiling

2. Steam pressure

3. Micro over

4. Cold pack method => not for vegetables and meats.

11.write short notes on preservation of food using low temperatue?

preservation by use of low temperature

Low temperature preservation is used commonly to retard chemical reactions and action of food enzymes. Therefore there is a gradual decrease in the activity of microorganism and also the spoilage of food.

The growth and metabolic reaction of microorganisms depend upon the enzymes and the rate of enzyme reactions directly affected by temperature.

During low temperature metabolic activity is arrested. Food enzymes are inactivated.

Low temperature methods:

1. Chilling / cold storage.

2. Freezing / frozen storage.

3. Freeze during / Lyophilization.

Chilling / cold storage:

1. It involves cooling by ice or by mechanical refrigeration.

2. It is used to prevent the growth and reduce the metabolic activity of microbe.

3. Temperature is 0 –15C.

4. Ice crystals can be used to store fish, meat during transportation.

5. Use of mechanical refrigerator. E.g. food storage in industry.

Factors:

1. Temperature:

Lower the temperature of storage, the greater the cost. The temperature is selected on the basis of

1. Kind of food.

2. Time.

3. Condition of storage. Certain foods have an optimal storage temperature or range of temperature well above the freezing point and may be damaged by lower temperature.

E.g.: banana should be kept in the refrigerator, best at about 13.3 to 16.7C.

2. RH:

The optimal Rh depends on the temperature, composition of the atmosphere, ray treatments.

Low RH => loss of moisture and hence weight, witting and softening of vegetables and shrinkage of fruits.

High RH => growth of spoilage microorganisms.

E.g.: yeast => 90 –92%

Molds => 85 –90%

Changes in RH and T during storage may cause sweating or precipitation of moisture on the food, so favors microbial spoilage. E.g.: slime on the moist surface of sausage.

3. Ventilation:

To prevent the development of stale odors and flavors, and maintain uniform RH throughout the room. It adequate ventilation is not provided; food in local areas of high humidity may undergo microbial decomposition.

4. Composition of storage atmosphere:

It is controlled by the introduction of Co2, ozone or other gases called as gas storage.

1. Food remains unspoiled for a longer period.

2. Rh may be maintained.

3. Keeping quality is maintained.

4. Higher storage temperature can be used without shortening the keeping time of food eg. Optimal CO2 concentration.

Eggs 2.5 %, Beef 10%, Bacon 100%, Apples concentration of O2 and CO2 is significant.

5. Irradiation :

UV lamps have been installed in rooms for the storage of meat & cheese.

Freezing / Frozen storage :

The selection & preparation of foods for freezing – fruits & vegetables are selected on the basis of their suitability for freezing & their maturity & are washed, trimming, cut vegetables are scalded/ blanched & fruits may be packed in a syrup.

Meats are selected to minimize enzymatic & microbial changes. Most foods are packaged before freezing, but some foods in small pieces. E.g. Strawberries may be frozen before package.

Scalding or blanching is done:

1. Inactivation of plant enzymes that involve toughness.2. Reduction in microorganisms of the food.3. enhancement of green color 4. wilting of leafy vegetables making them pat

Freezing of foods:

Freezing of foods depends on;

1. Temperature.

2. Circulation of air.

3. Kind of food

4. Size and shape of package.

FreezingQuick freezing Sharp /slow freezing

1. –15 to –29 C for 30 min 1. –15 to –29 C for 3-4 hrs till 72 hrs

2. No food damage 2. Damage of food by crystal formation.

3. Done by: 3. Done by the natural air circulation or

a. Direct immersion of food / package in through electrical fans.

Refrigerant. E.g.: fish in brine

b. Indirect contact (-17.8 to –45.6 c)

c. Air blast freezing (-17.8 to –34.4C)

Rigid air is blown.

Advantage of quick freezing:

1. Shorter period.

2. Prompt prevention of microbial growth.

3. Rapid slowing of enzyme action.

Dehydrofreezing: fruits and vegetables have about half there moisture removed before freezing.

Changes during freezing:

1. Expansion in volume of food.

2. Ice crystals formation may crush cells.

3. Frozen condition chemical and enzymatic reaction proceed slowly.

E.g.: meat, poultry, fish products, proteins may irreversibly dehydrated.

Oxidation

Meat -> red myoglobin ------------- brown metmyoglobin

On surface

Fats (meat, fish) ----- oxidized and hydrolysed

4. Metacryotic liquid:

Unfrozen, concentrated solutions of sugars, salts may ooze from packages of fruits or concentrates during storage as a viruses material.

5. Fluctuation in temperature results in ice crystal formation.

6. Deracination may occur.

7. Freeze burn :

when ice – crystals evaporate from the area at the surface this defect is observed. The spot appears dry, grainy and brownish, tissues become dry and tough.

E.g.: fruits, vegetables, meat, poultry and fish.

8. During freezing vegetative cells die soon but some may remain for a longer period of time.

Changes during thawing:

1. Drip / bleeding:

The pink or reddish liquid that comes from meat during thawing.

2. Leakage:

The liquid oozing out of fruits or vegetables on thawing.

3. The wilting and flabiness of physical damage during freezing.

4. Thawing refers to sudden heating and sudden cooling. The damage of food is due to the freezing and storage but do not become evident earlier. Some of the liquid during thawing may be reabsorbed by the food particles or may remain as such.

If the thawed fleshed foods are below 3.3 C can be used but otherwise food should be discarded.

Effects of freezing:

1. Lethal effects:

Rapid cooling of cells from optimal to 00 c may also result in death and referred to as cold shock, where there is change in lipid membrane damage the permeability of cell or to the release of repair enzyme inhibitors. E.g.: ribonuclease inhibitors

2. Sub – lethal effects:

During enumeration of frozen food there may be reduction but not tree death of organisms. Some may be injured or damaged are called as freeze – injured, frost injured or metabolically injured. Freezing of micro organisms in a food may result in cryoinjuiry.

Response of microorganisms to freezing:

Freezing depends on type of microorganisms usually found in foods involved in preservation. There are various factors involving freezing.

1. On the basis of sensitivity of microorganisms during freezing they can be classified as 3 different groups:

a. Susceptible or sensitive => e.g.: yeast, mould, gram-negative bacteria, and vegetative cells.

b. Moderately resistance => e.g. Staphylococcus, Enterococcus, gram-positive bacteria.

c. Resistant => e.g. Spore forming organisms.

2. Freezing also depends on the freezing rate. Critical range of temperature lead to death of microbes than during rapid freezing.

3. It also depends on the kind of food normally used for presentation. The food used for preservation by freezing usually gets spoiled due to

a. High moisture content.

b. Availability of O2

c. Salt and sugary environment.

4. Freezing also depends on the change in PH or altered acidity or alkalinity in food.

5. During freezing there is increase in moisture content and formation of intracellular crystals. This usually results in altered permeability in membrane and cell wall. Thus results in osmotic imbalance or osmotic shock favoring cell lyses. Intracellular lie crystals are harmful to cells than extra cellular ice crystals.

6. The initial killing rate during freezing is rapid, but it is followed by a gradual reduction of microorganisms are referred as storage death.

PRESERVATION BY USE OF DRYING

Introduction:

Drying is referred to as the removal of water or lowers the water activity or reduces the amount of available moisture.E.g., Dried fish => salt, condensed milk => sweet.

a). Sun Drying Drying of food by exposure to suns rays.

b). Dehydrated / Desiccated Drying by artificial means under controlled air flow, T and RB

c). Condensed Drying where moisture removal from liquid substances

d). Evaporated Similar to dehydrated.

Product Before drying moisture % After drying moisture %1. Milk2. Egg3. Beef4. Apple juice

90

74

60

86

5

2.9

1.5

6.2

Methods of drying:

1. Solar drying:

Direct sun’s rays

E.g., Raisins, figs, pears, peaches, rice, fish

2. Drying by mechanical dryers:

Passage of heated air to food under controlled RH.

a) Use of KLIN / EVAPORATOR:

They are used in form house

Natural draft from heated air brings drying.

b) Forced draft drying:

Heated air moves across the food usually in tunnels or food moved in conveyor belts through heated air.c) Spray dried:

Spraying of liquid into a current of dry, heated air.d). Drum dried:

Passage over a heated drum, with or without vacuum.3. Freeze drying:

Sublimation of water from frozen food by means of a vacuum and heat.E.g., Meat, Poultry, seafood’s and fruits.

4. Drying during smoking:E.g., wool smoke desired flavors and preservative are uses. Meat 43 – 71 C for few hrs to several days prevents mold growth.

It has HCHO, phenol, cresol, methyl and ethyl esters, ketones etc.5. Other methods:

a. Electronic Heatingb. Foam – mat drying ->Lipid whipped to foam, dried with warm air, crushed to powder, as is pressure – gun puffing of

partially dried foods to give a porous structure facilitate further drying.c. Tower Drying ->Dehumified air at 30 C or less. E.g. Tomato concentrate, milk and potatoes.

Factors:1. Temperature2. Relative humidity of air3. velocity of air4. time of drying

If all these not accounts may lead to case hardening where rapid, evaporation of moisture from the surface than diffusion from the interior leads to hard, horny, impenetratable surface film that hinders further drying.Process:Before Drying, Drying and after Drying:Before reception into plant:

Food has to be inspected without any contamination as;1. Milk -> Pure from udder in low, may be contaminated by handlers, process, and equipments.

2. Meat/ Poultry -> Due to soil, intestinal activity, handlers, equipments.3. Fish -> By intestinal activity, surface slime, and handlers.4. Egg -> Handlers, equipments, hatched hen and soil.

Before Drying:1. Selection: a. Elimination of spoiled foods.

b. Rejection of cracked, dirty foods.c. Sorting for size, maturity and soundness.

2. Washing:Especially fruits and vegetables. These procedures are followed to remove soil and adhering materials and removes

microbes. Water must be pure as it may also acts as a source of contaminate if poor quality of water is used.E.g., Egg -> Moisture helps the bacteria to penetrate the shell.3. Peeling:

May be done by hand, machine, lye bath or abrasion. It reduce the number of microorganisms are on the surface.

4. Sub division:Slicing, cutting should not increase number of organisms but will do so if equipment is not adequately cleansed and

sanitized5. Alkali Dip: It may reduce the microbial population. E.g., Raisins, Grapes, etc -> Hot 0.1 – 1.5 % lye / Na2CO3 6. Scalding / Blanching:

a. Sulfuring of light colored fruits and certain vegetables.b. Fruits -> 1000 – 3000 ppm of SO2 gasc. Vegetables -> dipping after blanching or spraying of sulfite solution.d. Helps to maintain an attractive light color, conserve vit C, vit A, repels insect, kills many microorganisms.

Drying:1. Heat2. Freeze drying

After Drying:1. Sweating: Storage in boxes or tins. It is for equalization of moisture or addition of moisture to a desired level.E.g., Dehydration of meat at 60 C -> leads to growth of Staph. aureus ., so that 1000C applicable.2. Packing:

Packed the foods after drying for protection against moisture contamination with microbes, insects.3. Pasteurization:

Fruits usually during package -> 30 to 70 min – time, 70 to 100% - RH, 65.6 to 850C – Temperature.Microbiology of dried foods:

1. Dried fruits: Mold spores may be seen.2. Dried vegetables: Few 100’s per gram to million of organisms due to the improper pretreatment. E.g.: Bacillus,

Micrococcus, Clostridium, E.coli, Enterobacter, Pseudomonas, Streptococci and Lactobacillus, Leuconostoc.3. Dried eggs: Coli forms, spore formers, molds, Micrococcus, Streptococci.4. Dried milk: Spore formers, Thermoduric, Streptococci, Micrococcus.

Intermediate moisture foods: (IMF)1. Commercially prepared foods haves 20-40% moisture and are non-refrigerated shelf stability are IMF.2. They have reduced water activity.E.g.: Candies, Jams, jellies, honey, bakery items etc.3. Aw may be 0.75 and 0.85 for IMF.4. They can be adjusted by the addition of sugar, salt or glycerols.

4. WRITE SHORT NOTES ON PRESERVATION OF FOODS BY FOOD ADDITIVES.

PRESERVATION OF FOODS BY FOOD ADDITIVES

INTRODUCTION

1) A food additive is a substance or mixture of substances, other than the basic food stuff, is present in food as a result of any aspect of production, processing, storage or packaging.

2) The definition emphasizes one interpretation of a food additive, i.e.; it is an intentional additive. There food additives are specifically added to prevent the deterioration or decomposition of a food have been referred to as chemical preservatives.

3) This decomposition may be caused by micro organisms, by food enzymes, or by purely chemical reactions. The inhibition of the growth and activity of micro organisms is one of the main purposes of the use of chemical preservatives

4) Preservatives may inhibit micro organisms by interfering with their cell membranes, their enzymes activity or their genetic mechanisms.

Factors that influence the effectiveness of chemical preservatives in killing micro organisms or inhibiting their growth.

a. Concentration of the chemicalb. Kind, number, age & previous history of the organismc. Temperatured. Timee. The chemical & physical characteristics of the substrate in which the organism is found.

The ideal antimicrobial preservative:

A chemical preservative should have a wide range of antimicrobial activity.

Should be nontoxic to human being or animals Should be economical Should not have an effect on the flavor, taste or aroma of the original food Should not be inactivated by the food or any substance in the food Should encourage the development of resistant strains Should kill rather than inhibit micro organisms

Organic acids and their salts:

Lactic, acetic, prop ionic & citric acids or their salts may be added to or

developed in foods

. Citric acid is used in syrups, drinks, Citric acid is used in syrups, drinks,jams &

Jellies

Lactic and acetic acids are added to brines of various kinds, green olives, etc.

Propionates:

Sodium or calcium propionate is used most extensively in the prevention of mold growth & rope development in baked foods & for mold inhibition in many cheese foods and spreads.

Experimentally, or on a limited scale, they have been used in butter, jams, jellies, apple slices & malt extract

They are effective against molds, with little or number inhibition of most yeast and bacteria.

Benzoates:

The sodium salt of benzoic acid has been used extensively as an antimicrobial agent in foods.

It has been incorporated into jams, jellies, carbonate (beverages, fruit salads, pickles, fruit juices etc.

Sorbates:

Sorbic acid, as the calcium, sodium or potassium salt, is used as a direct antimicrobial additive in foods.

It is widely used in cheeses, cheese products, baked goods, beverages, syrups, fruit juices, jellies, jams, dried fruits & pickles.

Sorbic acid & its salts are known to inhibit yeast & molds but are less effective against bacteria.

Acetates:

Derivatives of acetic acid

Dehydroacetic acid has been used to impregnate wrappers for cheese to inhibit the growth of molds

Acetic acid is more effective against yeast & bacteria than against molds.

Nitrites and Nitrates

Combinations of these various salts have been used in curing solutions & curing mixtures for meats.

Nitrites decompose to nitric acid, which forms nitrosomyoglobins when it reacts with the heme pigments in meats & thereby forms a stable red colour.

They are currently added in the form of sodium nitrite, potassium nitrate.

Recent works has emphasized the inhibitory property of nitrites towards Clostrium botulinum in meat products.

Sulfur dioxide and Sulfites:

The Egyptians and Romans burned sulfur to form sulfur dioxide as a means of sanitizing their wine – making equipments & storage vessels.

Today sulfur dioxide and sulfites are used in the wine industry to sanitize equipment to reduce the normal flora of the grape must.

Ethylene propylene oxide:

Ethylene oxide kills all micro organisms; propylene oxide, although it kills many micro organisms.

The primary uses have been as sterility for packaging materials, fumigation of water houses, & “cold sterilization” of numerous plastics, chemicals, pharmaceuticals, syringes & hospital supplies.

They have also been used successfully in dried fruits, dried eggs, cereals, dried yeast and spices

Sugar and salts:

Sodium chloride is used in brines & curing solutions or is applied directly to the food

Enough may be added to slow or prevent the growth of microorganisms or only enough to permit an acid fermentation to take place.

Salt has been reported to have the following effects.

It causes with osmotic pressure & hence plasmolysis of cells

It dehydrates foods by drawing out from the microbial cells.

It ionizes to yield the chlorine ion, which is harmful to organism

It reduces the solubility of oxygen in the moisture,

It sensitizes the cells against carbon dioxide

It interferes which the action of proteolysis enzymes.

Sugars, such as glucose or sucrose, owe their effectiveness as preservatives to their ability to make water unavailable to organisms and to their osmotic effect.

Examples of foods preserved by high sugar concentration are sweetened condensed milk, fruits in syrups, jellies & candies.)

UNIT-2

1.Discuss the food poisoning and food borne inflections.

FOOD BORNE INFECTIONS & INTOXICATIONSIntroduction :

Food borne diseases may be of 2 types,1. food borne infections2. food borne intoxications.

Food borne intoxication is by the presence of microbial toxin formed in the food. Food borne infection is caused by the microbe’s entry into the body through ingestion of contaminated food & the

reaction of the body to their presence or to their metabolites. Food borne infection can be divided into 2 types are [i] food that does not support growth of pathogens but merely carries them. Eg. Diphtheria, Dysentry, Typhoid fever, Brucellosis, Cholera, Infectious hepatitis, Q fever.[ii] food that serve as a culture medium for the growth of the pathogens to no.s that will increase the infection of the consumer of the food. Eg. E. coli, Salmonella, V.parahaemolyticus. Outbreak of infections are explosive in 2nd type.

CLASSIFICATION OF FOOD BORNE DISEASESFood borne diseases

PoisoningsInfections

Chemical poisonings Intoxications Enterotoxigenic Invasive

Poisonous Poisonous MicrobialSporulation Growth Intestinal Systemic Other

Plant tissues Animal tissues intoxications & lysis mucosa Tissues

Algal Mycotoxins Bacterial toxinsMuscle Liver

Toxins

Enterotoxins Neurotoxins Interferes with

Carbohydrate metabolism

FOOD BORNE DISEASES [BACTERIAL]

Intoxications Infections

1. Staphylococcal intoxication – an enterotoxin - 1. Salmonellosis– Enterotoxin & cytotoxin

S. aureus. 2. Cl. Perfringens - Enterotoxin

2. Botulism – neurotoxin – Cl. botulinum. 3. B. cereus – Exoenterotoxin - Gastroenteritis

4. Enteropathogenic E.coli – Enterotoxin - EPEC

5. Others: Vibrio parahemolyticus, Yersiniosis,

Shigellosis, Bacillus.

FOOD BORNE INTOXICATION

Staphylococcus

Introduction:

Food poisonings is caused by the ingestion of the enterotoxin formed in food during the growth of S. aureus.

The toxin is enterotoxin because it causes gasteroenteritis or inflammation of the lining of the intestinal tract.Organism:

Cluster of grapes or in pairs and short chains, Golden yellow colonies are formed on solid media. Coagulase positive, aerobes, facultative anaerobes, some strains are salt tolerant [10-20% Nacl]. Fairly tolerant of dissolved sugars [50-60% sucrose], Fermentative & preteolytic but do not produce obnoxious odour

[unattractice]. Based on serology, 6 distinct enterotoxins are classified [type A, B, C1, C2, D, E], A most effective toxin, Toxin

production varies with food involved.

Water activity [0.86 – aerobes, 0.90 – anaerobes], pH [ 4.8 – aerobes, 5.5 – anaerobes], Temperature [370C – optimum growth, 25 – 45oC – minimum, 4 – 460C - Survive], 660C – 12 mins, 600C – 78 to 83 mins are necessary to destroy the organisms in food.

D value – 60oC – 7.7 mins – Decimal reduction time, Radiation to kill Staphylococci is gamma rays on moist foods – 0.37 to 0.488 Mrad of gamma rays on moist foods.

Enterotoxin character :

Simple protein with molecular weight between 26,000 – 30,000 is a single polypeptide chain are cross linked by a disulphide bridge to form a cystine loop.

Organism is heat labile but toxin is heat stable. Type A & D mainly cause disease. Increased concentration of toxin is necessary to cause disease.

Toxin gets inactivated at 190.6oC. Temperature affects the toxin production [ 370C – 12 hrs, 180C – 3 days, 90C – 7 days, 4 – 6.70C - 4 days].

Foods involved :

Bakery food products [cream biscuits], Milk and milk products, Cured meat, Ham, Poultry and poultry products, Salads, egg and egg products.

Disease :

Incubation period [2 – 4 hrs] – first symptom seen. Common symptoms are salivation, nausea, vomiting, abdominal cramping, diarrhea, dysentry.

In some cases, vomiting, headache, muscular cramping, sweating, chills, weak pulse, respiratory tract problems [ cannot swallow] these may be the secondary symptoms.

Decreased death rate and disease can be cured within 4 days. Active organism secretes enterotoxin into food Food eaten Enterotoxin affects gut giving

gasteroenteritisEnterotoxin ingested along with food affects cells

Enterotoxin affects vomit receptors Water & Sodium pumps out of the cell

Vomiting center in the brain stimulated Diarrhea, fluid and electrolyte loss.

Vomiting Dehydration

Conditions for outbreak :

Food must contain enterotoxin producing Staphylococci. Food must be a good culture medium for growth & toxin production by the Staphylococci. Temperature must be favourable and enterotoxin bearing food may be ingested.

Prevention of outbreaks :

Prevention of contamination of food with Staphylococci. Killing of Staphylococci growth. Prevention of Staphylococci growth. Contamination of foods can be reduced by :

1. general methods of sanitation.2. Using ingredients free from cocci – eg. Pasteurised milk than raw milk.3. By keeping employees away from foods who have colds, boils, carbuncles, etc.4. Adequate refrigeration of food.5. Addition of bacteriostatic substances such as serine or antibiotic.

CLOSTRIDIUM BOTULINUM [INTOXICATION]Introduction :

Neurotoxin is produced by Clostridium botulinum which causes disease called Botulism. Death in infants is within 3 – 6 days & adults is 6 – 9 days. Organism is Gram positive, anaerobes, gas forming rod shaped bacteria which occurs in soil. Antigen are classified based on toxigenicity as A,B,C,D,E,F,G – 7 types. Type A Highly toxic to humans than B Type B, F & G Less toxic to man. Type C Cow, Cattle, other animals. Type D Cattle. Type E Fish and fish products.

Growth and toxin production :

The factors that influence the growth of organism are nutrient content of food [canned food, meat & fish], pH, temperature, oxidation - reduction potential, salt concentration, moisture content.

Contamination of food may be due to soil. Toxin is produced at pH 4.5, Organism must autolyse or sporulate to produce toxin. Non-proteolytic toxins are fully activated, These can be activated by binding with trypsin. Medium must have glucose or maltose for growth & toxin production. Medium should have nitrogen source, carbon source, casein and protein. Temperature [350C], pH [acidic – toxin production, Neutral – growth, anaerobic environment.

Nacl inhibits the growth of the organisms.Toxins :

Toxins are protein substances produced by the organism during the growth and it is thermolabile. Denaturation of the toxin is at 800C for 5 – 6 mins [type A], 900C for 15 mins [type B]. Radiation is used for toxin denaturation because it sterilizes deeply. Type A & B spores are highly heat resistant and the D valve is 1210C – 0.21 min – Type A, 1000C – 0.003 to 0.017

mins – Type E.Foods involved :

Meat, string beans, sweet corn, beets, fish, asparagus, spinach, canned foods [ proteolytic – odor, non-proteolytic – gas production].

Disease :

Incubation period [12 – 36 hrs], symptoms include nausea, vomiting, diarrhea, fatigue, dizziness, headache, constipation, double vision, difficult in swallowing & speaking, mouth dryness, throat constriction, swollen & coated tongue.

Temperature is normal or subnormal, involuntary muscles become paralyzed, paralysis spreads to the respiratory tract, heart & death results due to respiratory failure.

Symptoms are similar for type A,B,E poisoning but nausea, vomiting & urinary retention usually more severe with type E toxin.

Treatment [antitoxin administration, artificial respiration, keeping the patient isolated, maintaining the fluid balance in the body].

Neurotoxin ingested with food Neurotoxin passes through gut mucosa into blood stream

Toxin spreads throughout the body through bloodstream

Toxin binds to nerve at the junction This results in paralysis.

Conditions for outbreak :

Presence of the spores of type A, B, E. A food in which the spores can germinate & the clostridia can grow & produce toxin. Survival of the spores of the organism eg. Because of inadequate heating in canning or inadequate processing. Environmental conditions after processing that will permit germination of the spores, growth & toxin production by the

organism. Insufficient cooking of the food to inactivate the toxin. Ingestion of the toxin bearing food.

Prevention of outbreaks : Use of approved heat processes for canned foods. Rejection of all gassy [swollen] or otherwise spoiled canned foods. Refusal even to taste a doubtful food. Avoidance of foods that have been cooked, held & not well heated. Boiling of a suspected food for atleast 15 mins. Avoidance of raw or precooked foods. To prevent botulism from smoked fish :

1. good sanitation throughout production & handling.2. fish heated to atleast 820C – 30 mins in coldest part.3. fish be frozen immediately after packaging & kept frozen.4. all packaged be marked “ perishable – keep frozen”.

Infant botulism :

Infants --> predisposed constipation. Weakness, lack of sucking, loss of head control, diminished gag reflex. Death within 3 – 6 days. Milk, canned food [cereals] may cause intoxication.

Through mother’s infection.

2.Discuss The Food Borne Infection Of Salmonellosis

Introduction :

Causes gastroenteritis, Gram negative rods, non-spore formers, non-lactose fermenting organisms, facultative anaerobes, ferments glucose to produce gas and belongs to Enterobacteriaceae family.

Classification :

S. tyhi [ infect humans], S. typhimurium [infect animals]. Serotypes --> Somatic Ag [O], Capsular Ag [Vi], Flagellar Ag [H]. Temperature [370C – optimum, 450C – maximum, 6.7 – 7.80C - Minimum], pH [ neutral – optimum, 4.1 – minimum, 9 - maximum]. Increased H2S S. typphimurium, S. enteritis, decreased H2S S. typhi. Grows well in low acid foods [5.5 – 5.7]. Heat sensitive bacteria [ 660C – 12 mins, 600C – 78 to 83 mins]. D value [600C for 0.06 – 11.3 mins]. More concentration of bacteria can cause disease atleast 100 sp. Very less infective S.pullorum, Highly infective S.enteritis.

Sources of Salmonella contamination :

Humans [ Direct / Indirect, feces, handling, water contamination.] Animals [Direct / Indirect] – Dogs, cattle, cat [feces, infection, infected animal meat contamination, poultry products –

hen, chicken, meat & egg] due to improper processing, egg coated with fecal material. Increased refrigeration results in increased moisture & forms the pores & through this the organism enters.

Bakery products – sources through flies, cockroach, insects from infected to normal food.Foods involved :

Bakery products, Meat, Chicken, Milk and milk products – cheese, egg and egg products, cream cakes, Bacon & ham.Disease :

Incubation period [12 – 36 hrs]. Symptom includes gastrointestinal infection are nausea, vomiting, abdominal pain, diarrhea, headache, chills.

Other evidences are watery, greenish, foul-smelling stool, prostration, muscular weakness, faintness, moderate fever, restlessness, twitching, drowsiness.

Mortality is low [1%]. Diarrhea to death in 2 – 6 days. Symptoms persist for 2 – 3 days, followed by uncomplicated recovery. Carriers – 0.2 to 5 %. Organism ingested along with the food Organisms grows in the host gut Organism affects gut

giving gastroenteritis

Bacterial cells ingested along with the food Cells invade the tissues & release endotoxin

Fever, vomiting , Diarrhea [fluid & electrolyte loss] --- It leads to loss of water & sodium ions

Conditions for outbreak :

Food must contain or become contaminated with the salmonella bacteria. Good culture medium. Viable organism must be ingested.

Prevention of outbreak :

Avoidance of contamination of food [diseased human beings, animals, carriers, contaminated eggs]. Destruction of the organisms in food by heat.

Prevention of the Salmonella growth in foods by adequate refrigeration or by other means. In the prevention of contamination :

1. care and cleanliness in food handling & preparation.2. Food handlers should be healthy & clean.3. Rats & other vermin & insects should be kept away from foods.4. Ingredients used in food should be free of Salmonella.5. Food should not be allowed to stand at room temperature for any length of time.

GASTROENTERITIS

CLOSTRIDIUM PERFRINGENSOrganism :

Gram positive, non-motile, anaerobic, spore forming rods. Temperature [43 – 470C], pH [ 5 – 9 ], D value [900C – 0.015 to .71 mins]. Organism growth is inhibited by 5% Nacl. Toxins produced are A, B, C, D, E where A is infective and C is less infective.

Foods :

Raw foods, soil, sewage, animal feces, meat, fish, poultry.Disease :

Incubation period [8-24 hrs]. Abdominal pain, diarrhea, gas, fever, nausea, vomiting are the symptoms. Enterotoxin released in the gut during sporulation results in fluid accumulation in the intestine. Toxin is heat labile [ 600C – 10 mins – inactivated].

Symptoms:

1. Enterotoxin heat labile

2. Inactive at 60c for 10 min

3. Abdominal pain, diarrhoea with gas trouble, fever, nausea, vomiting.

4. Mortality is low.Conditions for outbreak :

Food contaminated with the organism. Food is not maintained properly. Inadequate cooling. Food is consumed without reheating.

Cells sporulate & produce enterotoxin

Infective dose:

Large number of vegetative cells in a food are required to produce food poisoning. The minimum seems to be about 7 x 105/g of food ingested but numbers as high as 108 /g or greater may be required.

Prevention of outbreaks:

1. Eat meat immediately after cooking.2. Cool cooked meats rapidly to 7ºC or below for storage and reheat to an internal T of above 70ºC before consumption.3. Store cooked chilled foods correctly and heat to an internal T of 70 C or above.4. Foods held hot before consumption should be maintained at 60 C or above.5. Avoid transferring spores from raw to cooked meat during boiling, slicing, mincing but not using common utensils and

observing good hygiene.6. Adequate & rapid cooling of cooked foods.7. Reheating.8. Personal hygiene.9. Sanitation.

3.What is foodborne disease? 

Foodborne disease is caused by consuming contaminated foods or beverages.  Many different disease-causing microbes, or pathogens, can contaminate foods, so there are many different foodborne infections. 

In addition, poisonous chemicals, or other harmful substances can cause foodborne diseases if they are present in food.  More than 250 different foodborne diseases have been described. 

Most of these diseases are infections, caused by a variety of bacteria, viruses, and parasites that can be foodborne.  Other diseases are poisonings, caused by harmful toxins or chemicals that have contaminated the food, for example, poisonous mushrooms.  

These different diseases have many different symptoms, so there is no one "syndrome" that is foodborne illness.  However, the microbe or toxin enters the body through the gastrointestinal tract, and often causes the first symptoms there, so nausea, vomiting, abdominal cramps and diarrhea are common symptoms in many foodborne diseases. 

Many microbes can spread in more than one way, so we cannot always know that a disease is foodborne.  The distinction matters, because public health authorities need to know how a particular disease is spreading to take the appropriate steps to stop it. 

For example, Escherichia coli O157:H7 infections can spread through contaminated food, contaminated drinking water, contaminated swimming water, and from toddler to toddler at a day care center.  Depending on which means of spread caused a case, the measures to stop other cases from occurring could range from removing contaminated food from stores, chlorinating a swimming pool, or closing a child day care center.  4.What are the most common foodborne diseases?  The most commonly recognized foodborne infections are those caused by the bacteria Campylobacter, Salmonella, and E. coli O157:H7, and by a group of viruses called calicivirus, also known as the Norwalk and Norwalk-like viruses.  Campylobacter is a bacterial pathogen that causes fever, diarrhea, and abdominal cramps.  It is the most commonly identified bacterial cause of diarrheal illness in the world.  These bacteria live in the intestines of healthy birds, and most raw poultry meat has Campylobacter on it.  Eating undercooked chicken, or other food that has been contaminated with juices dripping from raw chicken is the most frequent source of this  infection.  Salmonella is also a bacterium that is widespread in the intestines of birds, reptiles and mammals.  It can spread to humans via a variety of different foods of animal origin.  The illness it causes, salmonellosis, typically includes fever, diarrhea and abdominal cramps.  In persons with poor underlying health or weakened immune systems, it can invade the bloodstream and cause life-threatening infections.  E. coli O157:H7 is a bacterial pathogen that has a reservoir in cattle and other similar animals.  Human illness typically follows consumption of food or water that has been contaminated with microscopic amounts of cow feces.  The illness it causes is often a severe and bloody diarrhea and painful abdominal cramps, without much fever.   In 3% to 5% of cases, a complication called hemolytic uremic syndrome (HUS) can occur several weeks after the initial symptoms.  This severe complication includes temporary anemia, profuse bleeding, and kidney failure.  Calicivirus, or Norwalk-like virus is an extremely common cause of foodborne illness, though it is rarely diagnosed, because the laboratory test is not widely available.  It causes an acute gastrointestinal illness, usually with more vomiting than diarrhea, that resolves within two days. 

Unlike many foodborne pathogens that have animal reservoirs, it is believed that Norwalk-like viruses spread primarily from one infected person to another.  Infected kitchen workers can contaminate a salad or sandwich as they prepare it, if they have the virus on their hands.  Infected fishermen have contaminated oysters as they harvested them. 

Some common diseases are occasionally foodborne, even though they are usually transmitted by other routes.  These include infections caused by Shigella, hepatitis A, and the parasites Giardia lamblia and Cryptosporidia.  Even strep throats have been transmitted occasionally through food. 

In addition to disease caused by direct infection, some foodborne diseases are caused by the presence of a toxin in the food that was produced by a microbe in the food.  For example, the bacterium Staphylococcus aureus can grow in some foods and produce a toxin that causes intense vomiting. 

The rare but deadly disease botulism occurs when the bacterium Clostridium botulinum grows and produces a powerful paralytic toxin in foods.  These toxins can produce illness even if the microbes that produced them are no longer there. 

Other toxins and poisonous chemicals can cause foodborne illness.  People can become ill if a pesticide is inadvertently added to a food, or if naturally poisonous substances are used to prepare a meal.  Every year, people become ill after mistaking poisonous mushrooms for safe species, or after eating poisonous reef fishes.  5.How are foodborne diseases diagnosed?   The infection is usually diagnosed by specific laboratory tests that identify the causative organism.  Bacteria such as Campylobacter, Salmonella, E. coli O157 are found by culturing stool samples in the laboratory and identifying the bacteria that grow on the agar or other culture medium. 

Parasites can be identified by examining stools under the microscope.  Viruses are more difficult to identify, as they are too small to see under a light microscope and are difficult to culture.  Viruses are usually identified by testing stool samples for genetic markers that indicate a specific virus is present.  Many foodborne infections are not identified by routine laboratory procedures and require specialized, experimental, and/or expensive tests that are not generally available. 

If the diagnosis is to be made, the patient has to seek medical attention, the physician must decide to order diagnostic tests, and the laboratory must use the appropriate procedures.  Because many ill persons to not seek attention, and of those that do, many are not tested, many cases of foodborne illness go undiagnosed. 

For example, CDC estimates that 38 cases of salmonellosis actually occur for every case that is actually diagnosed and reported to public health authorities

6.How are foodborne diseases treated?  There are many different kinds of foodborne diseases and they may require different treatments, depending on the

symptoms they cause.  Illnesses that are primarily diarrhea or vomiting can lead to dehydration if the person loses more body fluids and salts

(electrolytes) than they take in.  Replacing the lost fluids and electrolytes and keeping up with fluid intake are important. If diarrhea is severe, oral rehydration solution such as Ceralyte*, Pedialyte* or Oralyte*, should be drunk to replace the

fluid losses and prevent dehydration.  Sports drinks such as Gatorade* do not replace the losses correctly and should not be used for the treatment of diarrheal illness. 

Preparations of bismuth subsalicylate (e.g., Pepto-Bismol)* can reduce the duration and severity of simple diarrhea.   If diarrhea and cramps occur, without bloody stools or fever, taking an antidiarrheal medication may provide

symptomatic relief, but these medications should be avoided if there is high fever or blood in the stools because they may make the illness worse.  *CDC does not endorse commercial products or services7.How do public health departments track foodborne diseases? 

Routine monitoring of important diseases by public health departments is called disease surveillance.  Each state decides which diseases are to be under surveillance in that state.

  In most states, diagnosed cases of salmonellosis, E. coli O157:H7 and other serious infections are routinely reported to the health department. 

The county reports them to the state health department, which reports them to CDC.  Tens of thousands of cases of  these "notifiable conditions" are reported every year.  For example, nearly 35,000 cases of Salmonella infection were reported to CDC in 1998.

However, most foodborne infections go undiagnosed and unreported, either because the ill person does not see a doctor, or the doctor does not make a specific diagnosis.  Also, infections with some microbes are not reportable in the first place. 

To get more information about infections that might be diagnosed but not reported, CDC developed a special surveillance system called FoodNet.  FoodNet provides the best available information about specific foodborne infections in the United States, and summarizes them in an annual report. 

 In addition to tracking the number of reported cases of individual infections, states also collect information about foodborne outbreaks, and report a summary of that information to CDC. 

About 400-500 foodborne outbreaks investigated by local and state health departments are reported each year.  This includes information about many diseases that are not notifiable and thus are not under individual surveillance, so it provides some useful general information about  foodborne diseases.  

8.What are foodborne disease outbreaks and why do they occur?  An outbreak of foodborne illness occurs when a group of people consume the same contaminated food and two or more

of them come down with the same illness.  It may be a group that ate a meal together somewhere, or it may be a group of people who do not know each other at

all, but who all happened to buy and eat the same contaminated item from a grocery store or restaurant.  For an outbreak to occur, something must have happened to contaminate a batch of food that was eaten by a the group

of people.  Often, a combination of events contributes to the outbreak.  A contaminated food may be left out a room temperature for many hours, allowing the bacteria to multiply to high

numbers, and then be insufficiently cooked to kill the bacteria.  Many outbreaks are local in nature.  They are recognized when a group of people realize that they all became ill after a common meal, and someone calls the local health department.  This classic local outbreak might follow a catered meal at a reception, a pot-luck supper, or eating a meal at an understaffed restaurant on a particularly busy day. 

However, outbreaks are increasingly being recognized that are more widespread, that affect persons in many different places, and that are spread out over several weeks. 

For example, a recent outbreak of salmonellosis was traced to persons eating a breakfast cereal produced at a factory in Minnesota, and marketed under several different brand names in many different states. 

No one county or state had very many cases and the cases did not know each other.  The outbreaks was recognized because it was caused by an unusual strain of  Salmonella, and because state public

health laboratories that type Salmonella strains noticed a sudden increase in this one rare strain.  

In another recent outbreak, a particular peanut snack food caused the same illness in Israel, Europe and North America.  Again, this was recognized as an increase in infections caused by a rare strain of Salmonella.    The vast majority of reported cases of foodborne illness are not part of recognized outbreaks, but occurs as individual or "sporadic" cases. 

It may be that many of these cases are actually part of unrecognized widespread or diffuse outbreaks.  Detecting and investigating such widespread outbreaks is a major challenge to our public health system. 

This is the reason that new and more sophisticated laboratory methods are being used at CDC and in state public health department laboratories.  9.List out the information centers for food safety and foodborne diseases? 

National Food Safety Initiative   CDC's Food Safety Initiative home page   U.S. Food and Drug Administration   U.S. Food Safety and Inspection Service (FSIS)   U.S. Environmental Protection Agency   Role of the federal agencies in food safety   Gateway to government food safety information   Partnership for Food Safety Education/Fight BAC! TM   Food Safety Training and Education Alliance   Foodborne Illness Information Center   National Food Safety Education Month   Travelers' Health  

LABORATORY TESTING:

The procedure to be followed in testing the samples of food or specimens from human source upon receipt in the laboratory will depend on the type of food and the information available about the outbreak of food illness.

The first act in most laboratories is to make a microscopic examination of a preparation of the food stained by the Gram’s method. The smear is made from liquid or from the sediments from homogenized, centrifuged food.

The microscopic examination may give a clue to the causative if the sample has been properly refrigerated.

Preventive measures:

To keep foods as free as possible from contamination which pathogenic agents by selection of uncontaminated foods, by adequate pasteurization or other heat processing, by avoiding contamination from infected food handlers or carriers, and by generally good sanitary practice throughout the handling, preparation and serving of foods.

To eliminate opportunities for the growth of pathogens, toxigenic or infectious, in foods by adjustment of the composition, by prompt consumption after preparation, and by adequate refrigeration of perishable foods if they must be hold for any considerable time, keeping foods warm for long periods is especially to be avoided.

To reject suspected foods

To educate the public better concerning the causes and prevention of food borne illness and the dangers involved.

FOOD SANITATION AND PLANT SANITATION:

Employee health standards:

Introduction:

The food industry sanitarian is concerned which specific aseptic practices in the preparation, processing, and packaging of the food products of a plant and the health of cleanliness and sanitation of plant and the health of employee.

Food and plant sanitation:

Specific duties in connection which the food products may involve quality control and storage of raw products, the provision of a good water supply; prevention of the contamination of the foods at all stages during processing from equipment, personnel, & the vermin; and supervision of packaging and ware housing of finished products.

The supervision of cleanliness and sanitation of plant and premises includes not only the maintenang of clean and well sanilized surfaces of all equipment toughing the foods but also generally goods house keeping in and the plant and adequate treatment and disposal of wastes.

Employee health standards:

Duties affecting the health of the employees include provision of a potable water supply, supervision of matters of personal lygiene, regulation of sanitary facilities in the plant and in plant operated of plant lighting, heating and ventilation. The sanitarian may also participate in training employees in sanitary practices.

For the most part, sanitarians concern themselves chiefly with general aspects of sanitation, making inspections, consulting with personnel responsibless for details of canitation and executives directing such work, and training personnel in sanitation.

SEWAGE WASTE TREATMENT AND DISPOSAL:

INTRODUCTION:

The food sanitation is concerned directly or indirectly with the adequate treatment and disposal of wastes from the industry. Solid and concentrated wastes ordinarily are kept separate the watery wastes and may be used directly for food, feed fertilizers, or other purpose; may first be concentrated dried, or fermented (ex: pea vine silage);or may be carted away to available land as unusable waste.

WASTE TREATMENT:

Care is taken to keep out of the waste waters as much wasted liquid or solid food material as possible by taking precautions to avoid introduction into the watery waste of drip, leakage, overflow, spillage, large residues in containers, foam, frozen on and food dust during the handling and processing of the food.

I t is recommended that sewage of human origin be kept separate from other plant waters because of the kept separate from other plant waters because of the possible presence of human intestinal pathogens.

Such sewage may be turned in to a municipal system.

Wastes from food plants ordinarily contain a variety of organic compounds, which range from simple and readily oxidizable kinds to those which are complex and difficult to decompose.

The strength of the sewage or food waste containing organic matter is expressed in terms of biochemical oxygen

demand ( BOD), which is the quantity of O2 used by aerobic microorganisms and reducing compounds in the

Stabilization of decomposable matter during a selected time at a certain temperature.

A period of 5 days at 20oC is generally used, and results are expressed as 5 days BOD.

Wastes from a food plant to be emptied into a body of water must either be so greatly diluted by that water must be treated first to reduce the oxidizable compounds to a harmless level.

Preliminary treatments of food- plant wastes by chemical means may be employed, but most systems of treatment and disposal depend on

1. Screening out of large particles.

2. Floating of fatty and other floating materials

3. Sedimentation of as much of the remaining solids

4. Hydrolysis, fermentation and putrefaction of complex organic compounds and finally5. Oxidation of the remaining solids inn the water to a point where they can enter a municipal sewage treatment and disposal systems.

BIOLOGICAL TREATMENT AND DISPOSAL:

Dilution, by running waste waters into a large body of water.

Irrigation, in which wastewaters are sprayed onto shallow artificial ponds (with or without treatments)

Use of trickling filters; made of crushed rock, coke, filter tile, etc.,

Use of the activated- sludge method, in which wastewater is inoculated heavily with sludge from a previous reaction.

Use of anaerobic tanks of various kinds, where settling, hydrolysis, putrefaction and fermentation take place.

FOOD BORNE:

POISONINGS, INFECTION AND INTOXICATION

NON BACERIAL:

Introduction:

Some food borne disease outbreaks are not caused by bacteria or their toxins but results from mycotoxins, viruses, rickettsiae, parasitic worms, or protozoa or from the consumption of food contaminated with toxin substances.

10.Write a detailed account on mycotoxins and the key management steps to prevent mycotoxin contamination.

Mycotoxins:

Mycotoxins are fungal metabolites. Some are highly toxic to many animals potentially toxic to human beings. Recent concern is related to their carcinogenic properties and their presence in many food items.

FUNGI AND HUMAN BEINGS:

The fungi include the moulds, yeasts, blights, rusts and mushrooms.

Many fungi are useful. Some are edible. Ex: Mushrooms and single cell protein from yeast.

Other is widely used in industrial and food fermentation.

Ex: Aspergillus oryzae is used in the production of soy sauce, miso and sake and moulds take part in the ripening of certain cheese.

Some mushrooms are harmful or poisonous to humans, but in contrast, moulds have generally been regarded as harmless.

Many fungi can be isolated from plants, including Alternaria, Rhizopus, Fusarium, Cladosporium, Helminthosporium and Chaetomium.

The two predominant genera of fungi in stored products are probably Penicillium and Aspergillus, members of which produce mycotoxins.

The syndrome resulting from the ingestion of toxin in a mold- contaminated food is referred to as mycotoxicosis.

AFLATOXIN:

Aflatoxins are produced by certain strains of A.falvus and A. parasiticus.

CHEMISTRY:

The two major metabolites or aflatoxins have been designated B, and G1 because they fluoresce Blue(B1) and Green (G1).B2 and G2 are the dihydroderivatives of B1 and G1.

TOXICITY:

Aflatoxin B1, the most toxic of the aflatoxins, is toxic to various animals. Many of the other aflatoxin have been shown to be toxic or carcinogenic to different species of fish, mammals and poultry.

SIGNIFICANCE IN FOODS:-

Many foods will support the growth of toxigenic strains if inoculated, including various dairy products, bakery products, fruit juices, cereals and forage crops.

In most cases, the growth of a toxigenic strain and the elaboration of aflatoxin occurs following harvesting or formulation of the product.

Peanuts, cottonseeds, and corn, however, differ significantly in that these products are susceptible to fungal invasion, growth and mycotoxin production before harvesting.

The contamination and potential for aflatoxin production in these crops is related to insect damage, humidity, weather conditions.

OTHER TYPES OF MYCOTOXIN:

Patulin: Produced by Penicillium expansum

OchratoxinProduced by Asperillus ochraceus

Luteoskyrin Produced by Penicillium islandicum

Roquefortine Produced by P. roqueforti

QUALITY CONTROL:

Quality of foods and food products may be defined as the degree of excellence of the various characteristics that influence consumer acceptance as well as consumer safety.

The selection of a particular food by a discerning consumer is made by the judgment of all the physical senses that is, tough, smell, taste and hearing.

Consumer safety requires the evaluation of food quality with respect to nutritional quality, hygienic condition and keeping storage.

MICROBIOLOGICAL EXAMINATION OF FOOD:-

Introduction

The stated chief purposes of microbiological criteria for foods are to give assurance:

1. That the foods will be acceptable from the Public health standpoint that is will not be responsible for the spread of infectious disease or for food poisoning.

2. That the foods will be of satisfactory quality3. The foods will have keeping qualities that should be expected of the product.4. Sampling for tests is a problem since the lack of homogeneity in most foods makes location, size and number

of samples significant.5. Standards usually are based on total numbers of organisms, numbers of organisms, numbers of indicator

organisms or numbers of pathogens.

INDICATOR ORGANISMS:-

It may be necessary to carry out a microbiological examination of a food for one or more of a number of reasons.

Escherichia coli is a natural component of the human gut flora and its presence in the environment, or on foods, generally implies some history of contamination of faecal origin.

Traditional the group chosen has been designated the coliforms- those organisms capable of fermenting lactose in the presence of bile at 37C.

This will include most strains of E. coli but also includes organisms such as Citrobactor and Enterobactor.

DIRECT EXAMINATION:-

. When examining foods, the possibility of detecting the presence of microorganisms by looking at a sample directly under the microscope should not be missed.

. A small amount of material can be mounted and teased out in a drop of water on a slide, covered with a cover slip, and examined.

CULTURAL TECNIQUES:-

The full microbiological examination usually requires that individual viable propagules are encouraged to multiply in liquid media or on the surface, or with in the matrix, of a medium solidified with agar.

A SELEATION OF MEDIA COMMONLY USED IN FOOD MICROBIOLOGY:

MEDIUM USE

1. Plate count agar Aerobic mesophilic count

2. Mac Conkey broth MPN of coliforms in water

3. Brilliant Green/Lactose/ Bile broth MPN of coliforms in food

4. Violet red/ bile/Glucose agar Enumeration of Enterobacteriaceae.

5. Crystal violet /Azide / Blood agar Enumeration of faecal Streptococci.

6. Baird- Parker agar Enumeration of S. aureus

7. Vassiliadis broth Selection enrichment of Salmonella.

8. Thiosulfate / bile/ citrate/ Sucrose agar Isolation of Vibrios

9. Rose Bengal/ Chloramphenicol agar Enumeration of moulds and yeasts

10. Mac Conkey agar E. coli

ENUMERATION METHODS:-

Plate counts-

It has already been suggested that to count microorganisms in a food sample by direct microscopy has a limited sensitivity because of the very small sample size in the field of view at the magnification needed to see microorganisms, especially bacteria.

In a normal routine laboratory the most sensitive methods of detecting the presence of a viable bacterium is to allow it to amplify itself to form a visible colony.

This forms the basis of the traditional pour plate and spread plate and most probable number counts.

ALTERNATIVE METHODS- .Cultural methods are relatively labour intensive and require time for adequate growth to occur. . Many food microbiologists also consider that the traditional enumeration methods are not only too slow but lead to an

over dependence on the significance of numbers of colony forming units. . A number of methods have been developed which aim to give answer of redox to as “Rapid methods”.

1. Dye- reduction test:-

A group of tests which have been used for some time in the dairy industry dependent on the response of a number of redox dye to the presence of metabolically active microorganisms.

They are relatively simple and rapid to carry out at low cost. The redox dyes are able to take up electrons from an active biological system and this results in a

change of colour.

2. Immunological methods:-

ELISA.

3. DNA/RNA methodology:-

PCR method

11.Write an account on idli fermentation and the micro organisms involved in the fermentation.

FERMENTED FOOD

IDLI:

The idli , also romanized "idly" or "iddly" and plural "idlis", is a savory cake popular throughout South India. The cakes are usually two to three inches in diameter and are made by steaming a batter consisting of fermented black lentils (de-husked) and rice. The fermentation process breaks down the starches so that they are more readily metabolized by the body.

Most often eaten at breakfast or as a snack, idlis are usually served in pairs with chutney, sambar, or other accompaniments. Mixtures of crushed dry spices such as milagai podi are the preferred condiment for idlis eaten on the go.

History

Although the precise history of the modern idli is unknown, it is a very old food in southern Indian cuisine. One mention of it in writings occurs in the Kannada writing of Shivakotiacharya in 920 AD,[1] and it seems to have started as a dish made only of fermented black lentil. Chavundaraya II, the author of the earliest available Kannada encyclopaedia, Lokopakara (c. 1025), describes the preparation of Idli by soaking Urad dal (black gram) in butter milk, ground to a fine paste and mixed with the clear water of curd, and spices.[2] The Kannada king and scholar Someshwara III, reigning in the area now called Karnataka, included an idli recipe in his encyclopedia, the Manasollasa, written in Sanskrit ca. 1130 A.D. There is no known record of rice being added until some time in the 17th century. It may have been found that the rice helped speed the fermentation process. Although the ingredients used in preparing idli have changed, the preparation process and the name have remained the same.

In ancient Tamilnadu, Puttu or pittu (made out of rice flour)was a very popular food and the recipe was very similar to modern idli .

Idli was derived from a tamil word "Ittu Avi" means pour it (or put it)and steam it. Later it turned into (maruviyadu) Ittavi and then into ittali.

The earliest Tamil writings are traced to about 300 BC, but references to edibles and food habits abound in literature between 100 BC and 300 AD (Idaicchangam). Dosai and Vadai, as said above, were popular. Tamils ate meals of all kinds, as well as fish.

Preparation

Idli batter is poured into the round indentations of the idli pans (pictured) and placed into a pressure cooker.

To make idli, two parts uncooked rice to one part split black lentil (Urad dal) are soaked. The lentils and rice are then ground to a paste in a heavy stone grinding vessel (attu kal). This paste is allowed to ferment overnight, until it expands to about 2½ times its original volume. In the morning, the idli batter is put into the ghee-greased molds of an idli tray or "tree" for steaming. These molds are perforated to allow the idlis to be cooked evenly. The tree holds the trays above the level of boiling water in a pot, and the pot is covered until the idlis are done (about 10-25 minutes, depending on size). The idli is somewhat similar to the dosa, a fried preparation of the same batter.

In the olden days, when the idli mold cooking plates were not popular or widely available, the thick idli batter was poured on a cloth tightly tied on the mouth of a concave deep Cooking pan or tava half filled with water. A heavy lid was placed on the pan and the pot kept on the boil until the batter was cooked into idli. This was often a large idli depending on the circumference of the pan. It was then cut into bite-size pieces and eaten.

Contemporary Idlis and variations

Southern Indians have brought the popular idli wherever they have settled throughout the world. Cooks have had to solve problems of hard-to-get ingredients, and climates that do not encourage overnight fermentation. One cook noted that idli batter, foaming within a few hours in India, might take several days to rise in Britain. The traditional heavy stones used to wet-grind the rice and dal are not easily transported. Access to Indian ingredients before the advent of Internet mail order could be virtually impossible in many places. Chlorinated water and iodized salt interfere with fermentation.

Newer "quick" recipes for the idli can be rice- or wheat-based (rava idli). Parboiled rice, such as Uncle Ben's can reduce the soaking time considerably. Store-bought ground rice is available, or Cream of Rice may be used. Similarly, semolina or Cream of Wheat may be used for rava idli. Yoghurt may be added to provide the sour flavor for unfermented batters. Prepackaged mixes allow for almost instant idlis, for the truly desperate. However, the additional health benefits of fermentation process will be lacking. Idli Burger is another variation that can be made easily.

Besides the microwave steamer, electric idli steamers are available, with automatic steam release and shut-off for perfect cooking. Both types are non-stick, so a fat-free idli is possible. Table-mounted electric Wet grinders may take the place of floor-bound attu kal. With these appliances, even the classic idlis can be made more easily.

The plain rice/black lentil idli continues to be the popular version, but it may also incorporate a variety of extra ingredients, savory or sweet. Mustard seeds, fresh chile peppers, black pepper, cumin, coriander seed and its fresh leaf form (cilantro), fenugreek seeds, curry leaves , fresh ginger root, sesame seeds, nuts, garlic, scallions, coconut, and the unrefined sugar jaggery are all possibilities. Filled idlis contain small amounts of chutneys, sambars, or sauces placed inside before steaming. Idlis are sometimes steamed in a wrapping of leaves such as banana leaves or jackfruit leaves.

A variety of idlis are experimented these days, namely, standard idli, mini idlis soaked in sambar, rava idli, Kancheepuram idli, stuffed idli with a filling of potato, beans, carrot and masala, ragi idli, pudi idli with the sprinkling of chutney pudi that covers the bite-sized pieces of idlis, malli idli shallow-fried with coriander and curry leaves, and curd idli dipped in masala curds.

Ramasseri Idli : Ramasseri, an offbeat village in Palakkad is known all over Kerala for the idlies it make - the delicious Ramasseri Idli. Spongy and soft Ramasseri Idli is slightly different in shape from the conventional idlies. It is a little flat and round. Ramasseri Idli is eaten with Podi mixed in coconut oil. The beginning was from a Muthaliyar family living near Mannath Bhagavathi Temple in Ramasseri near Elappullly.The recipe of Ramasseri idli dates back to about one century,which again is a trade secret. The Muthaliyar family was migrated to Palakkad from Kanchipuram in Tamil Nadu. The new generation in the profession says that the secret of the recipe and taste were handed down to them from grand old women of the community. Now the idli business is confined to four families in Ramasseri. Selection of rice is very important in making Ramasseri idli. Usually the verities used are Kazhama, Thavalakannan, Ponni etc. The taste starts from the boiling of paddy itself. Drying and dehusking are also important. It is done in a particular way. The combination of rice and black gram is also equally important. For 10 kg of rice, one kg of black gram is used. Idli is made only after four hours of fermentation. Boiling of the idli is done on a cloth covered on the mud pot using firewood. This provides special taste to the preparation.

Leftover Idli can be torn into crumbs and used for preparing dishes such as Idli fry and Idli Upma.

Picture gallery

Idli and Vada served with sambar and two type of chutneys (green and red) on banana leaf.

The South Indian staple breakfast item of idli, sambar, and vada served on a banana leaf. Note the stainless steel plates and cups; characteristic of south Indian dining tables.

Tatte Idli: variations from Karnataka

Sambar idli: Idli soaked in sambar. Chutney is the best companion for this dish.

MTR idli: Famous Mavalli Tiffin Room idli served with pure ghee and sambar. Pure ghee is poured on steaming idli and relished with chutney or sambar.

Button Idli. This usually contains fourteen idli and is therefore called "fourteen idli". However this name came from Floating idli (small idlies floating on sambar, rasam or butter milk)

Sanna(s), a Goan variant of idli.

12.Write a brief account on bread making.

BREAD

Bread is one of the fermented food products, the fermentation being brought about mainly by yeast.

Methods of bread production:-

The bread is made by a number of procedures. But the most common methods utilized are,

1. Sponge dough2. Straight dough3. Continuous mix4. Liquid ferment.Sponge dough:-

This is the predominant bread making method using by the baking industry.

Sponge comprises of about 65% of about total flour + a portion of total dough water + yeast & yeast food, its first mixed. This mixing period is brief. The sponge is then discharged into a trough where it will undergo a fermentation period of 4-5 hrs from starting temperature of about 25 0 C to a final rise by 6 0C. Due to exothermic reactions brought about by yeast activity. Sponge volume will increase due to CO2 production.

At the end of sponge fermentation, the sponge is transferred into a dough mixture. The balance of the flour, water remaining ingredients are added into the mixture and allow mixing. First at low speed & at higher speed until the dough is completely mixed. At this point dough has been transformed from a sticky wet appearing nature into smooth cohesive dough characterized by glossy sheen, upon addition of water & input of energy wheat protein & lipids form gluten. The dough due to the unique nature of gluten able to retain the gas & is thereby leavened.

The mixed dough is placed in troughs & allows resting for 20-30 minutes.

Dividing the dough is the next stage. The dough is cut into pieces of desired weight by a machine & conveyed on a belt to a rounder where the rough appearing pieces are removed such that the pieces are held for a rest period of 8-12minutes to compensate for the loss of gas.

The dough pieces are conveyed to moulding machines, which transform the round dough pieces into cylinders. Automatic moulders feed the dough cylinders into bread pans.

Pans-containing dough pieces are placed in fermentation unit called proof-boxes, for last fermentation period prior to baking. They are held at 35-43 0C at a relative humidity of 80-95% for 60minutes. The proof lobes are placed in oven for baking. Gas within the dough expands. Steam & alcohol vapors also contribute to this expansion. Enzymes are active until the bread reaches 75 0C. At this temperature starch gelatinizes & dough structure is set. When the bread surface temperature reaches the 130-140 0C sugars & soluble proteins react chemically to produce an attractive crust colors. The center of the leaf doesn’t exceed 100 0c.

Remaining stages in bread making process includes cooling of the baked bread, slicing, wrapping & distribution to stores.

Function of yeast in bread making:-

Major function of yeast in bread making includes:

1. Leavening2. Flavor development3. Dough maturing

1. Leavening:- Dough is usually leavened by bread yeast which ferment the sugars in the dough & produce Co2 &

alcohol. There is little or no growth during the first 2hrs, after the yeast is added to dough, but some growth in 2-4hrs & then there is a decline in growth in 4-6hrs. Fermentation by the yeast begins as soon as the dough mixed & continuous until the temperature of oven inactivates the yeast enzyme.

During fermentation conditioning of the dough takes place when the flour proteins (gluten) mature i.e., it becomes elastic & springy & are therefore capable of retaining maximal amount of CO2 produced by the yeast. The conditioning results from action on the gluten by: -

Proteolytic enzymes in the flour from the yeast & Malt. Reduction in pH by the acids added & formed.

Dough conditioners called yeast foods are added which include ammonium salts to stimulate the yeast &

various salts.

Example:- Kbro3,Cao,KIO 3 to improve dough characteristics.

Adding increases the rate of gas production by the yeast,

More yeast. Sugar or amylase bearing malt Yeast food.The main objective of the baking during leavening is to have enough gas produced & to have dough

that will hold the gas at the right time.

Heterofermentative lactic acid bacteria & saccharolytic anaerobes can accomplish leavening. Leavening by chemicals is accomplished by using baking powder or by C02 gas, which may be incorporated directly, or ammonium bicarbonate may be used.

2. Flavor development:- Fresh bread has a pleasing & appealing flavor. Bread flavor is derived from 2 main sources.

Yeast fermentation Crust browsing

Yeast fermentation:- The characteristics flavor yeast raised bread arises from yeast fermentation & subsequent reaction of

fermentation products with other dough compounds during baking. During baking some of these flavor compounds escape & other react with amino acids & other compounds of the dough to yield characteristic flavor of bread. Fermentation byproduct formed during yeast fermentation is organic esters, acids, alcohol, carboxyl compounds. Some of the organic compounds formed during fermentation may arise from bacterial action.

Lactic acid bacteria found in dough are associated with yeast. In addition to Saccharomyces cerevisiae other yeast may be responsible for characteristic flavor of certain breads.

Breakdown products of flavor proteins play an important role in flavor & color development. Yeast proteolytic enzyme modify peptones & polypeptides for growth, a portion of these product react with sugars to impart desirable flavor upon baking.

Crust Browning:-

The extent of crust browning is influenced by previous activities of in the Saccharomyces cerevisiae dough. A part of bread flavor is formed in the crust during baking & then diffuses into crumb where it becomes observed.

Compounds produced during Fermentation & Baking:-

Organic acids Aldehydes/Ketones Alchol Carbonyl compounds

Butyric Acetaldehyde Ethanol Furfural

Succinic HCHO n-propanol Glyoxal

Propionic Acetone Isobutanol Methional

Isobutyric Diacetyl Amyl alcohol Hydroxy methyl furfural

Isovaleric Acetoin Isoamyl alcohol

Palmitic

Acetic

Lactic

Formic

Caproic

Valeric

Lauric

Myristic

3. Dough Maturing:-

The changes caused by yeast in the dough are called dough maturing or ripening. A properly matured

dough exhibits optimum rheological properties [optimum dough balance of extensibility & Elasticity] such that it may be machined well & will lead to bread with desirable volume & crumb characteristics, some of the reactions leading to dough maturing are as follows.

Alcohol & Co2 are derived from yeast fermentation. Alcohol is water miscible & since appreciable amounts are formed. It influences the colloidal nature of the flour proteins & alters the interfacial tension within the dough. Some of the CO2 dissolves in aqueous phase & form carbonic acid, which lowers the pH of the system. CO2 also distends the dough work into the dough system.

Ammonia from ammonium sulphate & ammonium chloride added to the dough, as yeast foods are assimilatory S. cerevisiae causing a liberation of H2SO4 & HCl. These acids along with carbonic aid lower the pH, Which in turn influences

Gluten hydration & Swelling The reaction rate of enzyme in the dough Oxidation-reduction reactions & Various chemical reactions.

ACIDOPHILUS MILK Use:

A lactobacillus acidophilus organism are able to get themselves implanted in the large intestine of human beings through regular consumption of product and thereby controls GI disorders such as diarrhea, dyspepsia, constipation, flatulence, colitis in adults and children.

13.Write a brief account on Wine production.

Harvest in late summer (August), without tools, mainly by men.  

Grapes were placed into baskets.  

The baskets were emptied into a treading vat.  

Treading the grapes underfoot.  

The remainder was pressed (wrung out) in a cloth or a sack to gather all liquid.

 

Fermentation (i.e. grape juice turns into wine - sugar turns into alcohol); the wine has to be sealed, otherwise it turns into vinegar.

one or two days of fermentation - light wine

several weeks - heavy wine

longer period - wine turns into vinegar From the scant evidence it seems that red wine was very common in ancient Egypt; white wine is first securely attested in the third century AD.

 

In the tomb of Tutankhamun wine jars were found with the inscription: irp nDm 'Sweet wine'. Partly dried grapes, (because they contain concentrated sugar) were used for producing sweet wine.

Sweet wines have a high alcohol content and are therefore longer resistant

'Blended wine' (irp smA), appears on labels found at Malqata. It is not certain whether wine of different years, vineyards or types were mixed.

 

Other wines mentioned in Egyptian texts were made from sweet fruits, such as dates and fig.

 

14. Explain the production of Beer.

There are four main ingredients in a real Beer:

WATER - The quantity and variety of dissolved salts in the water used will play a great part in the character of the final beer. The salts play a part in the extraction of fermentable sugars from the grain as well as affecting the way the yeast behaves during fermentation. The total salts in Pilsen's water amounts to around 30 parts per million whereas in Burton on Trent UK, the content is 1220 parts per million. The main salts of interest are as follows; Calcium - increases the extract (efficiency of extracting sugars during mashing). It can also help to make the beer clearer. Sulphates - enhance the bitterness of the hops. It was Calcium Sulphate in the local water in Burton on Trent that helped to create the pale ale style of beer. Chlorides - help to enhance sweetness. These are relatively high in the waters of Dublin and London. This is where Porters and Stouts originated. Part of the modern brewing process involves modifying the content of these key ions to produce a water that is best suited to the style of beer being produced. .

MALT - Grapes can be made to release their sugars simply by crushing. In more Northern latitudes where grapes and sweet fruits do not readily grow ancient people turned to another source. It was probably discovered by accident that as a harvested grain started to germinate, it's sugar content seemed to increase. This was due to the conversion of starches in the grain into sugars as the seed began to germinate. If this process is stopped by drying at an optimal point in this process, the grain will contain some sugars plus a quantity of enzymes to aid the extraction of fermentable sugars. The process of mashing (see below) makes use of these enzymes to do just this job.

HOPS - Winemakers used to add aroma to their wines through adding spices and fruit. The favourite for brewers is to add the flower of the hop vine. When wine makers moved to ageing their wines in oak casks, they discovered that the wood performed a similar job but most modern beers are too light in flavour to cope with this process. The herbs and spices once added to wine also acted as a preservative. The hop cones added to beer also perform very well in this respect. The hops add alpha and beta acids that provide bitterness and aroma to the final product. Hops are chosen for their content in these products as required by the beer being produced. They are also added at different stages in the process depending on whether they are being used to provide bitterness or aroma. Our beers use hops to provide both bitterness and aroma.

YEAST - The first winemakers did not realise the spontaneous fermentation of their grapes was caused by the wild yeasts that collected on the skins of the grapes. Some styles of beers still make use of wild yeasts but as the yeast has such a contribution to make to the character of the final beer, most modern brewers prefer to control the yeast culture. They style of ales we produce uses top fermenting yeast. These are yeasts that form a foam on the top of the beer during fermentation. This foam is skimmed at a certain stage in the fermentation and used to start the next beer fermenting. These yeasts are used at higher temperatures. They are pitched in at around 15 deg C and the fermentation temperature rises as the yeast culture grows. The temperature can rise to 25C or more but must be controlled to prevent undesirable products being produced that can affect the final flavour. The sugar content of the liquid is monitored throughout the fermentation and the process is stopped when the desired alcohol strength is reached.

The Process

The malt is cracked (rolled between precisely set rollers) to just split the grains but not produce flour. This stage is critical as we just need grains that are split to release the sugars and enzymes. Grains that are crushed to a flour prevent the mash from being effective and can block filters etc later in the process. This cracked grain is mixed with water at a precisely controlled temperature of around 67 C. This is a temperature that stimulates the enzymes in the malt to convert starches to sugars that are released into the liquid now called a wort.

A process known as sparging is used to try to maximise the extraction by adding more water until the volume of liquid is correct and then recirculating the wort through the grain. Once the sugar extraction is completed 90-120 minutes, the wort is pumped through to a large boiler known as a 'copper'. The wort is now brought to the boil at which point the first batch of hops is added. Hops added at this stage are for bitterness. Any aroma imparted from the hops added at this stage will be boiled off. The wort is boiled for around 90 minutes before the aroma hops are added and the heat removed. After a short period of time, the wort is rapidly cooled and transferred to a fermentation vessel at around 17 deg C. The yeast is added as soon as conditions are right and fermentation generally starts in a few hours. It is important that the temperature is controlled within tight limits as this affects the fermentation products and hence characteristics of the final beer. After a few days, the sugar content and alcohol content reach a target value and the fermentation is stopped by cooling the beer below the yeast activation temperature. The yeast is removed and the beer is then pumped to conditioning tanks. It remains in these tanks for a few days to mature before being transferred to casks or bottles. Bottling involves an additional process to encourage further conditioning in the bottle. The bottled beer is not filtered or pasteurised so that the beer continues to develop once bottled as long as the environment is suitable. If the bottles are stored upright at 14-17 deg C, the yeast continues to ferment slightly and adds some condition to the beer. This yeast will also fall to the bottom of the bottle so the beer should be decanted in one go to prevent the yeast returning to suspension.

It is the control of this process from start to finish that ensures a high quality product. Realising this, we at 'Le Brewery' make great efforts to carefully control this process so that every bottle tastes as good as the last.

We look forward to your visit and feel sure you will enjoy our hand crafted traditional beers.

15.Write a brief note on Plant based fermented foods.

Miso is a traditional Japanese food produced by fermenting rice, barley and/or soybeans, with salt and the fungus kōjikin (the most typical miso is made with soy). The typical result is a thick paste used for sauces and spreads, pickling vegetables or meats, and mixing with dashi soup stock to serve as miso soup called Misoshiru a Japanese culinary staple. High in protein and rich in vitamins and minerals, miso played an important nutritional role in feudal Japan. Miso is still very widely used in Japan, both in traditional and modern cooking, and has been gaining world-wide interest. Miso is typically salty, but its flavor and aroma depend on various factors in the ingredients and fermentation process. Different varieties of miso have been described as salty, sweet, earthy, fruity, and savory, and there is an extremely wide variety of miso available.

History

The predecessor of miso originated in China during the 3rd century BC or earlier, and it is probable that this, together with related fermented soy-based foods, was introduced to Japan at the same time as Buddhism in the 6th century AD

During the Edo period miso was also called hishio and kuki.

Until the Muromachi era, miso was made without grinding the soybeans, somewhat like natto. In the Kamakura era, a common meal was made up of a bowl of rice, some dried fish, a serving of miso, and a fresh vegetable. In the Muromachi era, Buddhist monks discovered that soybeans could be ground into a paste, spawning new cooking methods where miso was used to flavor other foods.

VarietyBy flavor

The taste, aroma, texture, and appearance of any specific miso vary by miso type as well as the region and season for which the miso was made. The ingredients used, temperature and duration of fermentation, salt content, variety of kōji, and fermenting vessel all contribute. The most common flavor categories of soy miso are:

Shiromiso, "white miso" Akamiso, "red miso"

Kuromiso, "black miso"

Hatchomiso

White and red (shiromiso and akamiso) are the basic types of miso available in all of Japan as well as overseas. Different varieties are preferred in particular regions. For example, in the eastern Kantō region that includes Tokyo, the lighter shiromiso is popular, while in the western Kansai region encompassing Osaka, Kyoto, and Kobe, darker brownish hatchomiso is preferred, and akamiso is favoured in the Tokai area.

By ingredient

The raw materials used to produce miso may include any mix of soybeans, barley, rice, buckwheat, millet, rye, wheat, hemp seed, and cycad, among others. Lately, producers in other countries have also begun selling miso made from chick peas, corn, adzuki beans, amaranth, and quinoa. Fermentation time ranges from as little as five days to several years. The wide variety of Japanese miso is difficult to classify, but is commonly done by grain type, color, taste, and background.

mugi : barley tsubu : whole wheat/barley

aka : red, medium flavor

hatchō : aged (or smoked), strongest flavor, along with 'shiro' is most commonly used

shiro : rice, sweet white, fresh, along with 'hatcho' is most commonly used

shinshu: rice, brown color

genmai : brown rice

awase : layered, typically in supermarket

moromi : chunky, healthy (kōji is unblended)

nanban : chunky, sweet, for dipping sauce

inaka : farmstyle

taima : hemp seed

sobamugi : buckwheat

hadakamugi : rye

meri : made from cycad pulp, Buddhist temple diet

gokoku : "5 grain": soy, wheat, barley, proso millet, and foxtail millet

Many regions have their own specific variation on the miso standard. For example, the soybeans used in Sendai miso are much more coarsely mashed than in normal soy miso.

Miso made with rice (including shinshu and shiro miso) is called kome miso.

Using misoStorage and preparation

Miso typically comes as a paste in a sealed container, and should be refrigerated after opening. It can be eaten raw, and cooking changes its flavor and nutritional value; when used in miso soup, most cooks do not allow the miso to come to a full boil. Some people, especially those outside of Japan, go so far as to only add miso to preparations after they have cooled, to preserve the biological activity of the kōjikin. Since miso and soy foods play a large role in the Japanese diet, there are a variety of cooked miso dishes as well.

In food

Miso is a part of many Japanese-style meals. It most commonly appears as the main ingredient of miso soup, which is eaten daily by much of the Japanese population. The pairing of plain rice and miso soup is considered a fundamental unit of Japanese cuisine. This pairing is the basis of a traditional Japanese breakfast.

Miso is used in many other types of soup and souplike dishes, including some kinds of ramen, udon, nabe, and imoni. Generally, such dishes have the title miso prepended to their name (for example, miso-udon), and have a heavier, earthier flavor and aroma compared to other Japanese soups that are not miso-based.

Many traditional confections use a sweet, thick miso glaze, such as mochidango. Miso glazed treats are strongly associated with Japanese festivals, although they are available year-round at supermarkets. The consistency of miso glaze ranges from thick and taffy-like to thin and drippy.

Soy miso is used to make a type of pickle called "misozuke".These pickles are typically made from cucumber, daikon, hakusai, or eggplant, and are sweeter and less salty than the standard Japanese salt pickle. Barley miso, or nukamiso, is used to make another type of pickle.[4] Nukamiso is a fermented product, and considered a type of miso in Japanese culture and linguistics, but does not contain soy, and so is functionally quite different. Like soy miso, nukamiso is fermented using kōji mold.

Other foods with miso as an ingredient include:

dengaku (charcoal-grilled miso covered tofu) yakimochi (charcoal-grilled miso covered mochi)

miso braised vegetables or mushrooms

marinades: fish or chicken can be marinated in miso and sake overnight to be grilled.

corn on the cob in Japan is usually coated with shiro miso, wrapped in foil and grilled.

sauces: sauces like misoyaki (a variant on teriyaki) are common.

Nutrition and health

The nutritional benefits of miso have been widely touted by commercial enterprises and home cooks alike. However, claims that miso is high in vitamin B12 have been contradicted in some studies [1]. Part of the confusion may stem from the fact that some soy products are high in B vitamins (though not necessarily B12), and some, such as soy milk, may be fortified with vitamin B12. Some, especially proponents of healthy eating, suggest that miso can help treat radiation sickness, citing cases in Japan and Russia where people have been fed miso after the Chernobyl nuclear disaster and the atomic bombings of Hiroshima and Nagasaki. Notably, Japanese doctor Shinichiro Akizuki, director of Saint Francis Hospital in Nagasaki during World War II, theorized that miso helps protect against radiation sickness. Also some experts suggest that miso is a source of Lactobacillus acidophilus.

Olive:

The Olive (Olea europaea) is a species of small tree in the family Oleaceae, native to the coastal areas of the eastern Mediterranean region, from Lebanon, Syria and the maritime parts of Asia Minor and northern Iran at the south end of the Caspian Sea. Its fruit, the olive, is of major agricultural importance in the Mediterranean region as the source of olive oil.

Description

The Olive Tree is an evergreen tree or shrub native to the Mediterranean, Asia and parts of Africa. It is short and squat, and rarely exceeds 8–15 meters in height. The silvery green leaves are oblong in shape, measuring 4–10 cm long and 1–3 cm wide. The trunk is typically gnarled and twisted.

The small white flowers, with four-cleft calyx and corolla, two stamens and bifid stigma, are borne generally on the last year's wood, in racemes springing from the axils of the leaves.

The fruit is a small drupe 1–2.5 cm long, thinner-fleshed and smaller in wild plants than in orchard cultivars. Olives are harvested at the green stage or left to ripen to a rich purple colour (black olive). Canned black olives may contain chemicals that turn them black artificially.

History

The olive is one of the plants most cited in recorded literature. In Homer's Odyssey, Odysseus crawls beneath two shoots of olive that grow from a single stock.[1] The Roman poet, Horace mentions it in reference to his own diet, which he describes as very simple: "As for me, olives, endives, and smooth mallows provide sustenance."[2] Lord Monboddo comments on the olive in 1779 as one of the foods preferred by the ancients and as one of the most perfect foods.[3]

The leafy branches of the olive tree, olive leaf as a symbol of abundance, glory and peace, were used to crown the victors of friendly games and bloody war. As emblems of benediction and purification, they were also ritually offered to deities and powerful figures: some were even found in Tutankhamen's tomb.

Olive oil has long been considered sacred; it was used to anoint kings and athletes in ancient Greece. It was burnt in the sacred lamps of temples as well as being the "eternal flame" of the original Olympic Games. Victors in these games were crowned with its leaves. Today it is still used in many religious ceremonies.

According to Greek mythology the Olive tree, her gift to the people of Attica, won Athena the patronage of the city of Athens over Poseidon.

Cultivation and uses

An example of black olives.

The olive tree has been cultivated since ancient times as a source of olive oil, fine wood, olive leaf, and olives for consumption. The naturally bitter fruit is typically subjected to fermentation or cured with lye or brine to make it more palatable.

Green olives and black olives are washed thoroughly in water to remove oleuropein, a bitter carbohydrate. Sometimes they are also soaked in a solution of food grade sodium hydroxide in order to accelerate the process.

Green olives are allowed to ferment before being packed in a brine solution. American black ("California") olives are not fermented, which is why they taste milder than green olives.

It is not known when olives were first cultivated for harvest. Among the earliest evidence for the domestication of olives comes from the Chalcolithic Period archaeological site of Teleilat Ghassul in what is today modern Jordan.

The plant and its products are frequently referred to in the Bible, the Book of Mormon, the Qur'an, and by the earliest recorded poets. Farmers in ancient times believed olive trees would not grow well if planted more than a short distance from the sea; Theophrastus gives 300 stadia (55.6 km) as the limit. Modern experience does not always confirm this, and, though showing a preference for the coast, it has long been grown further inland in some areas with suitable climates, particularly in the southwestern Mediterranean (Iberia, northwest Africa) where winters are mild.

Olive plantation in Andalucia, Spain.

Olives are now cultivated in many regions of the world with Mediterranean climates, such as South Africa, Chile, Australia, Mediterranean Basin, Israel, Palestinian Territories and California and in areas with temperate climates such as New Zealand, under irrigation in the Cuyo region in Argentina which has a desert climate. They are also grown in the Córdoba Province, Argentina, which has a temperate climate with rainy summers and dry winters (Cwa)[11]; the climate in Argentina changes the external characteristics of the plant but the fruit keeps its original characteristics [12]. Considerable research supports the health-giving benefits of consuming olives, olive leaf and olive oil (see external links below for research results).

The olive tree provides leaves, fruit and oil. Olive leaves are used in medicinal teas.

Subspecies

There are at least five natural subspecies distributed over a wide range:

Olea europaea subsp. europaea (Europe) Olea europaea subsp. cuspidata (from Eritrea and Ethiopia south throughout East Africa, also in Iran to China)

Olea europaea subsp. guanchica (Canaries)

Olea europaea subsp. maroccana (Morocco)

Olea europaea subsp. laperrinei (Algeria, Sudan, Niger, India)

Cultivars

Small Olive Tree

Large Olive Tree

Olive Tree Leaves

Olive Tree Trunk

Olive Flowers

A young olive plant, germinated from a seed

Monumental tree in Apulia Region - Southern Italy

There are thousands of cultivars of the olive. In Italy alone at least three hundred cultivars have been enumerated, but only a few are grown to a large extent. The main Italian cultivars are 'Leccino', 'Frantoio' and 'Carolea'. None of these can be accurately identified with ancient descriptions, though it is not unlikely that some of the narrow-leaved cultivars most esteemed may be descendants of the Licinian olive. The Iberian olives are usually cured and eaten, often after being pitted, stuffed (with pickled pimento, anchovies, or other fillings) and packed in brine in jars or tins.

Since many cultivars are self sterile or nearly so, they are generally planted in pairs with a single primary cultivar and a secondary cultivar selected for its ability to fertilize the primary one, for example, 'Frantoio' and 'Leccino'. In recent times, efforts have been directed at producing hybrid cultivars with qualities such as resistance to disease, quick growth and larger or more consistent crops.

Some particularly important cultivars of olive include:

'Manzanillo', a large, rounded-oval fruit, with purple-green skin. Rich taste and thick pulp. A prolific bearer, grown around the world.

'Frantoio' and 'Leccino'. These cultivars are the principal participants in Italian olive oils from Tuscany. Leccino has a mild sweet flavour while Frantoio is fruity with a stronger aftertaste. Due to their highly valued flavour, these cultivars are now grown in other countries.

'Arbequina' is a small, brown olive grown in Catalonia, Spain, good for eating and for oil.

'Empeltre' is a medium-sized black olive grown in Spain, good for eating and for oil.

'Kalamata' is a large, black olive with a smooth and meatlike taste, named after the city of Kalamata, Greece, used as a table olive. These olives are usually preserved in vinegar or olive oil. Kalamata olives enjoy PDO (Protected designation of origin) status.[13]

'Koroneiki' originates from the southern Peloponese, around Kalamata and Mani in Greece. This small olive, though difficult to cultivate, has a high yield of olive oil of exceptional quality.

'Pecholine' or 'picholine' originated in the south of France. It is green, medium size, and elongated. The flavour is mild and nutty.

'Lucques' originated in the south of France (Aude département). They are green, large, and elongated. The stone has an arcuated shape. Their flavour is mild and nutty.

'Souri' (Syrian) originated in Lebanon and is widespread in the Levant. It has a high oil yield and exceptionally aromatic flavour.

'Nabali' is a Palestinian cultivar[14] also known locally as 'Baladi', which along with 'Souri' and 'Malissi' are considered to produce among the highest quality olive oil in the world.[15]

'Barnea' is a modern cultivar bred in Israel to be disease-resistant and to produce a generous crop. It is used both for oil and for table olives. The oil has a strong flavour with a hint of green leaf. Barnea is widely grown in Israel and in the southern hemisphere, particularly in Australia and New Zealand.

'Maalot' (Hebrew for merits) is another modern Israeli, disease-resistant, Eastern Mediterranean cultivar derived from the North African 'Chemlali' cultivar. The olive is medium sized, round, has a fruity flavour and is used almost exclusively for oil production.

'Mission' originated on the California Missions and is now grown throughout the state. They are black and generally used for table consumption.

Growth and propagation

Olive trees show a marked preference for calcareous soils, flourishing best on limestone slopes and crags, and coastal climate conditions. They tolerate drought well, thanks to their sturdy and extensive root system. Olive trees can be exceptionally long-lived, up to several centuries, and can remain productive for as long, provided they are pruned correctly and regularly.

The olive tree grows very slowly, but over many years the trunk can attain a considerable diameter. A. P. de Candolle recorded one exceeding 10 m in girth. The trees rarely exceed 15 m in height, and are generally confined to much more limited dimensions by frequent pruning. The yellow or light greenish-brown wood is often finely veined with a darker tint; being very hard and close-grained, it is valued by woodworkers.

The olive is propagated in various ways, but cuttings or layers are generally preferred; the tree roots easily in favourable soil and throws up suckers from the stump when cut down. However, yields from trees grown from suckers or seeds are poor; it must be budded or grafted onto other specimens to do well (Lewington and Parker, 114). Branches of various thickness are cut into lengths of about 1 m and, planted deeply in manured ground, soon vegetate; shorter pieces are sometimes laid horizontally in shallow trenches, when, covered with a few centimetres of soil, they rapidly throw up sucker-like shoots. In Greece, grafting the cultivated tree on the wild form is a common practice. In Italy, embryonic buds, which form small swellings on the stems, are carefully excised and planted beneath the surface, where they grow readily, their buds soon forming a vigorous shoot.

Occasionally the larger boughs are marched, and young trees thus soon obtained. The olive is also sometimes raised from seed, the oily pericarp being first softened by slight rotting, or soaking in hot water or in an alkaline solution, to facilitate germination.

Where the olive is carefully cultivated, as in Languedoc and Provence, the trees are regularly pruned. The pruning preserves the flower-bearing shoots of the preceding year, while keeping the tree low enough to allow the easy gathering of the fruit. The spaces between the trees are regularly fertilized. The crop from old trees is sometimes enormous, but they seldom bear well two years in succession, and in many instances a large harvest can only be reckoned upon every sixth or seventh season.

A calcareous soil, however dry or poor, seems best adapted to its healthy development, though the tree will grow in any light soil, and even on clay if well drained; but, as remarked by Pliny, the plant is more liable to disease on rich soils, and the oil is inferior to the produce of the poorer and more rocky ground.

In general, a temperature below 14 °F (-10 °C) may cause considerable injury to a mature tree, but (with the exception of juvenile trees) a temperature of 16 °F (-9 °C) will normally cause no harm.

Fruit harvest and processing

Most olives today are harvested by shaking the boughs or the whole tree. Another method involves standing on a ladder and "milking" the olives into a sack tied around the harvester's waist.Using olives found lying on the ground can result in poor quality oil.

In southern Europe the olive harvest is in winter, continuing for several weeks, but the time varies in each country, and also with the season and the kinds cultivated. A device called the oli-net wraps around the trunk of the tree and opens to form an umbrella-like catcher; workers can then harvest the fruit without the weight of the load around their neck. Another device, the oliviera, is an electronic tool that connects to a battery. The oliviera has large tongs that are spun around quickly, removing fruit from the tree. This method is used for olives used for oil. Table olive varieties are more difficult to harvest, as workers must take care not to damage the fruit; baskets that hang around the worker's neck are used.

The amount of oil contained in the fruit differs greatly in the various cultivars; the pericarp is usually 60–70% oil. Typical yields are 1.5-2.2 kg of oil per tree per year.

Traditional fermentation

Olives freshly picked from the tree contain phenolic compounds and oleuropein, a glycoside which makes the fruit unpalatable for immediate consumption. There are many ways of processing olives for table use. Traditional methods use the natural microflora on the fruit and procedures which select for those that bring about fermentation of the fruit. This fermentation leads to three important outcomes: the leaching out and breakdown of oleuropein and phenolic compounds; the creation of lactic acid, which is a natural preservative; and a complex of flavoursome fermentation products. The result is a product which will store with or without refrigeration.

One basic fermentation method is to get food grade containers, which may include plastic containers from companies which trade in olives and preserved vine leaves. Many bakeries also recycle food grade plastic containers which are well sized for olive fermentation; they are 10 to 20 litres in capacity. Freshly picked olives are often sold at markets in 10 kg trays. Olives should be selected for their firmness if green and general good condition. Olives can be used green, ripe green (which is a yellower shade of green, or green with hints of color), through to full purple black ripeness. The olives are soaked in water to wash them, and drained. 7 litres (which is 7 kg) of room temperature water is added to the fermentation container, and 800 g of sea salt, and one cup (300g) of white vinegar (white wine or cider vinegar). The salt is dissolved to create a 10% solution (the 800 g of salt is in an 8 kg mixture of salt and water and vinegar). Each olive is given a single deep slit with a small knife (if small), or up to three slits per fruit (if large, eg 60 fruit per kg). If 10 kg of olives are added to the 10% salt solution, the ultimate salinity after some weeks will be around 5 to 6% once the water in the olives moves into solution and the salt moves into the olives. The olives are weighed down with an inert object such as a plate so they are fully immersed and lightly sealed in their container. The light sealing is to allow the gases of fermentation to escape. It is also possible to make a plastic bag partially filled with water, and lay this over the top as a venting lid which also provides a good seal. The exclusion of oxygen is useful but not as critical as when grapes are fermented to produce wine. The olives can be tasted at any time as the bitter compounds are not poisonous, and oleuropein is a useful antioxidant in the human diet.

The olives are edible within 2 weeks to a month, but can be left to cure for up to three months. Green olives will usually be firmer in texture after curing than black olives. Olives can be flavored by soaking them in various marinades, or removing the pit and stuffing them. Herbs, spices, olive oil, feta, capsicum (pimento), chili, lemon zest, lemon juice, garlic cloves, wine, vinegar, juniper berries, and anchovies are popular flavorings. Sometimes the olives are lightly cracked with a hammer or a stone to trigger fermentation. This method of curing adds a slightly bitter taste.

16.Write a brief note on Tempeh Production.

Tempeh is a nutritional super hero. It is high in protein, dietary fiber, iron, potassium, calcium, and phytochemicals like isoflavones. It has been shown to lower cholesterol, high blood pressure and the risk of heart attack and stroke; reduce the risk of some cancers, like colon, breast, ovarian and prostate; ease certain menopausal symptoms; prevent and possibly even reverse the effects of osteoporosis and diabetes. To obtain these protective properties, researchers recommend consuming a minimum of 25 grams soy protein and 30-50 milligrams isoflavones daily. This works out to about 1-2 servings a day. One serving of tempeh, which is 1/2 cup (4 ounces), provides on average 19 grams soy protein, 60 milligrams isoflavones and 7 grams dietary fiber (28% RDA). Tempeh made with only soybeans has more soy protein and isoflavones than those with added grain. Whatever variety you choose, tempeh is the best source and easiest way to get lots of high quality protein, isoflavones and fiber in a minimally processed soy food. Each serving also supplies about 100 milligrams calcium (10% RDA), 550 milligrams potassium (16% RDA), and 5 milligrams iron (30% RDA).

2. Tempeh is a great choice for people who have difficulty digesting plant-based high-protein foods like beans and legumes or soy foods such as tofu. Because tempeh is a fermented soy product, its enzymes are partially broken down, making it easier to metabolize. It does not produce the unpleasant gastrointestinal discomfort and gas that some other plant-based proteins do. This fermentation process actually allows your body to more easily assimilate and absorb tempeh's nutrients. Besides being a terrific cholesterol-free easy-to-digest meat alternative, it is also ideal for people on low sodium diets. Unlike other fermented soy products, like miso which is very salty, tempeh is extremely low in sodium.

3. Tempeh has a pleasant, wonderfully unique nutty/mushroom flavor. It's rich and savory taste and firm texture makes it easy to create fantastic meals without a lot of fuss. It does not need much preparation or cooking time, making it a marvelously healthy fast food. Just add a little soy sauce or liquid hickory smoke seasoning to enhance its flavor. Then stir-fry, sauté, microwave, stew or bake it to make a variety of delightful dishes and sandwiches. To make a hearty entree in a short amount of time, all you need is tempeh, onions, mushrooms, peppers, olive oil, liquid seasoning, and some cooked brown rice or pasta. Thinly slice the tempeh. Sprinkle some soy sauce or liquid hickory (or mesquite) smoke seasoning on both sides of the slices. Slice the onions, mushrooms and peppers, and sauté in a little olive oil for a few minutes. Add the seasoned tempeh slices and sauté until lightly browned. Salt and pepper to taste.

17. Write a brief note on Country Salt Cured Ham and Bacon.

The dilemma facing pioneer mountain cooks was how to keep freshly butchered meat from spoiling without refrigeration. Hogs were butchered in the late fall when the temperature was down around 33 degrees, and while the meat was fresh, it was salt cured. The next spring any leftovers would be smoked under a fire of green hickory or peppered. Sausage was packed in the intestines of the hog, tied off and also hung in the smokehouse for curing. Salting, peppering, and smoking protected the meat from spoiling and from insects. Today it's that salt, pepper, and smoky flavor that we love in country ham, bacon, and sausage.

Clifty Farm's Country Ham

Clifty Farms country ham is from Tennessees oldest smokehouse. Slow bake or boil this salt cured and hickory smoked ham to serve with your home made biscuits or rolls and your holiday dinner will be one to remember. Serve lightly re-fried leftovers at breakfast with red-eye gravy. Four hours soaking recommended. Ogi:

Ogi is a fermented cereal porridge from West Africa, typically made from maize, sorghum, or millet. Traditionally, the grains are soaked in water for up to three days, before wet milling and sieving to remove husks. The filtered cereal is then allowed to ferment for up to three days until sour. It is then boiled into a pap, or cooked to make a stiff porridge.

The fermentation of ogi is performed by various lactic acid bacteria including Lactobacillus spp, and various yeasts including Saccharomyces and Candida spp.

Soy sauce:

Soy sauce (US), soya sauce (Commonwealth), or shoyu (Japan) is a fermented sauce made from soybeans (soya beans), roasted grain, water and salt. Soy sauce was invented in China, where it has been used as a condiment for close to 2,500 years. In its various forms it is widely used in East and Southeast Asian cuisines and increasingly appears in Western cuisine and prepared foods.

Production

Soy sauce is made from soybeans.

Traditional

Authentic soy sauces are made by mixing the grain and/or soybeans with yeast or kōji (麹, the mold Aspergillus oryzae or A. sojae) and other related microorganisms. Traditionally soy sauces were fermented under natural conditions, such as in giant urns and under the sun, which was believed to contribute to additional flavours. Today, most of the commercially-produced counterparts are fermented under machine-controlled environments instead.

Although there are many types of soy sauce, all are salty and earthy-tasting brownish liquids used to season food while cooking or at the table. Soy sauce has a distinct basic taste called umami by the Japanese (鮮 味 , literally "fresh taste"). Umami was first identified as a basic taste in 1908 by Kikunae Ikeda of the Tokyo Imperial University. The free glutamates which naturally occur in soy sauce are what give it this taste quality.

Soy sauce should be stored away from direct sunlight.

Artificially hydrolyzed

Many cheaper brands of soy sauces are made from hydrolyzed soy protein instead of brewed from natural bacterial and fungal cultures. These soy sauces do not have the natural color of authentic soy sauces and are typically colored with caramel coloring, and are popular in Southeast Asia and China, and are exported to Asian markets around the globe. They are derogatorily called Chemical Soy Sauce "化學醬油" in Chinese, but despite this name are the most widely used type because they are cheap. Similar products are also sold as "liquid aminos" in the US and Canada.

Some artificial soy sauces posed potential health risks due to their content of the chloropropanols carcinogens 3-MCPD (3-chloro-1,2-propanediol) and all artificial soy sauces pose health risks due to the unregulated 1,3-DCP (1,3-dichloro-2-propanol) which are minor byproducts of the hydrochloric acid hydrolysis [1].

Types

Soy sauce has been integrated into the traditional cuisines of many East Asian and South East Asian cultures. Soy sauce is widely used as a particularly important flavoring in Japanese, Thai, and Chinese cuisine. However, it is important to note that despite its

rather similar appearance, soy sauces produced in different cultures and regions are very different in taste, consistency, fragrance and saltiness. As such, it may not be appropriate to substitute soy sauces of one culture or region for another.

Chinese soy sauce

A bottle of Chinese soy sauce, artificially hydrolyzed, as clearly evident from the discoloration of the bottle due to addition of caramel coloring to mask the production method

Chinese soy sauce (simplified Chinese:; traditional Chinese:; pinyin: jiàngyóu; or chǐyóu) is primarily made from soybeans, with relatively low amounts of other grains. There are two main varieties:

Light or fresh soy sauce :A thin (non-viscous), opaque, dark brown soy sauce. It is the main soy sauce used for seasoning, since it is saltier, but it also adds flavour. Since it is lighter in color, it does not greatly affect the color of the dish. The light soy sauce made from the first pressing of the soybeans is called tóuchōu (simplified Chinese: 头抽; traditional Chinese: 頭抽), which can be loosely translated as first soy sauce or referred to as premium light soy sauce. Touchōu is sold at a premium because, like extra virgin olive oil, the flavor of the first pressing is considered superior. An additional classification of light soy sauce, shuānghuáng (雙 璜 ), is double-fermented to add further complexity to the flavour. These latter two more delicate types are usually for dipping.

Dark/old soy sauce: A darker and slightly thicker soy sauce that is aged longer and contains added molasses to give it its distinctive appearance. This variety is mainly used during cooking since its flavour develops under heating. It has a richer, slightly sweeter, and less salty flavour than light soy sauce. Dark soy sauce is partly used to add color and flavour to a dish.

In traditional Chinese cooking, one of the two types, or a mixture of both, is employed to achieve a particular flavour and colour for the dish.

Other types:

Thick soy sauce :Dark soy sauce that has been thickened with starch and sugar. It is also occasionally flavored with MSG. This sauce is not usually used directly in cooking but more often as a dipping sauce or poured on food as a flavorful addition.

Dark soy paste : Although not really a soy sauce, it is another salty soy product. It is one of the main ingredients in a dish called zhajiang mian, lit. "fried paste noodles").

Japanese soy sauce

Koyo organic tamari sauce

Buddhist monks introduced soy sauce into Japan in the 7th century, where it is known as "shoyu". The Japanese word "tamari" is derived from the verb "tamaru" that signifies "to accumulate," referring to the fact that tamari was traditionally from the liquid byproduct produced during the fermentation of miso. Japan is the leading producer of tamari.

Japanese soy sauce or shō-yu, is traditionally divided into 5 main categories depending on differences in their ingredients and method of production. Japanese soy sauces include wheat as a primary ingredient and this tends to give them a slightly sweeter taste than their Chinese counterparts. They also have an alcoholic sherry-like flavor. Not all soy sauces are interchangeable.

Koikuchi

Originating in the Kantō region, its usage eventually spread all over Japan. Over 80% of the Japanese domestic soy sauce production is of koikuchi, and can be considered the typical Japanese soy sauce. It is produced from roughly equal quantities of soybean and wheat. This variety is also called kijōyu (生 醤 油 ) or namashōyu (生しょうゆ) when it is not pasteurized.

Usukuchi

Particularly popular in the Kansai region of Japan, it is both saltier and lighter in color than koikuchi. The lighter color arises from the usage of amazake, a sweet liquid made from fermented rice, that is used in its production.

Tamari

Produced mainly in the Chūbu region of Japan, tamari is darker in appearance and richer in flavour than koikuchi. It contains little or no wheat; wheat-free tamari is popular among people eating a wheat free diet. It is the "original" Japanese soy sauce, as its recipe is closest to the soy sauce originally introduced to Japan from China. Technically, this variety is known as miso-damari (味噌溜り), as this is the liquid that runs off miso as it matures.

Shiro ("white")

A very light colored soy sauce. In contrast to "tamari" soy sauce, "shiro" soy sauce uses mostly wheat and very little soybean, lending it a light appearance and sweet taste. It is more commonly used in the Kansai region to highlight the appearances of food, for example sashimi.

Saishikomi ("twice-brewed") 

This variety substitutes previously-made koikuchi for the brine normally used in the process. Consequently, it is much darker and more strongly flavored. This type is also known as kanro shoyu (甘露醤油) or "sweet shoyu".

Shoyu (koikuchi) and light colored shoyu (usukuchi) as sold in Japan by Kikkoman, 1 litre bottles.

Newer varieties of Japanese soy sauce include:

Gen'en ("reduced salt")

Low-salt soy sauces also exist, but are not considered to be a separate variety of soy sauce, since the reduction in salt content is a process performed outside of the standard manufacture of soy sauce.

Amakuchi

Called "Hawaiian soy sauce" in those few parts of the US familiar with it, this is a variant of "koikuchi" soy sauce.

All of these varieties are sold in the marketplace in three different grades according to how they were produced:

Honjōzō hōshiki

Contains 100% naturally fermented product.

Shinshiki hōshiki

Contains 30-50% naturally fermented product.

Tennen jōzō

Means no added ingredients except alcohol.

All the varieties and grades may be sold according to three official levels of quality:

Hyōjun

Standard pasteurized.

Tokkyū

Special quality, not pasteurized.

Tokusen

Premium quality, usually implies limited quantity.

Other terms unrelated to the three official levels of quality:

Hatsuakane

Refers to industrial grade used for flavoring, powder.

Chōtokusen

Used by marketers to imply the best.

Perhaps the most well-known producer of Japanese soy sauce is the Kikkoman Corporation.

Taiwanese soy sauce

The history of soy sauce making in Taiwan can be traced back to southeastern China, in the provinces of Fujian and Guangdong. Later, the cultural and political separation between Taiwan and China since the end of the First Sino-Japanese War in 1895, when China ceded Taiwan to Japan, brought changes to traditional Chinese soy sauce making in Taiwan. Some of the top Taiwanese makers, such as Wan Ja Shan, Wei-Wong and Ve-Chung have adopted the more sophisticated Japanese technology in making soy sauce for the domestic market and more recently foreign markets as well.

Korean soy sauce

Korean soy sauce, (called Joseon ganjang, 조선간장, in Korean) is a byproduct of the production of doenjang (Korean fermented soybean paste). Joseon ganjang, thin and dark brown in color, is made entirely of soy and brine, and has a saltiness that varies according to the producer. Wide scale use of Joseon ganjang has been somewhat superseded by cheaper factory-made Japanese style soy sauce, called waeganjang (hangul). Currently, Korean soy sauce is made from dripping soy sauce chicken into a pan. This process is widely used because in the process of making soy sauce, you get the benefit of regular chicken. According to the 2001 national food consumption survey in Korea, traditional fermented ganjang comprised only 1.4% of soy sauce purchases.

Vietnamese soy sauce

Vietnamese soy sauce is called xì dầu, nước tương, or sometimes simply tương.

Indonesian soy sauce

Kecap manis Indonesian thick and sweet soy sauce is nearly as thick as molasses.

In Indonesia, soy sauce is known as kecap (or ketjap) (a catchall term for fermented sauces) from which according to one theory the English word "ketchup" is derived. Two main varieties exist:

Kecap asin 

Salty soy sauce, which is very similar to Chinese light soy sauce, but usually somewhat thicker and has a stronger flavor; it can be replaced by light Chinese soy sauce in recipes.

Kecap manis 

Sweet soy sauce, which has a thick, almost syrupy consistency and a pronounced sweet, treacle-like flavor due to generous addition of palm sugar. It is a unique variety; in a pinch, it may be replaced by molasses with a little vegetable stock stirred in.

Kecap inggris ("English fermented sauce"), or saus inggris ("English sauce") is the Indonesian name for Worcestershire sauce. Kecap Ikan is Indonesian fish sauce.

Malaysian soy sauce

In Singapore and Malaysia, soy sauce in general is dòuyóu (豆油); dark soy sauce is called jiàngyóu (醬油) and light soy sauce is jiàngqīng (醬清). Angmoh tauyew (紅貌豆油, lit. "foreigners' soy sauce") is the Hokkien name for Worcestershire sauce.

Malaysia, which has cultural links with Indonesia, uses the word 'kicap' for soy sauce. Kicap is traditionally of two types: kicap lemak and kicap cair. Kicap lemak is similar to kecap manis but with very much less sugar while kicap cair is the Malaysian equivalent of kecap asin.

Filipino toyo

A popular condiment in the Philippines, it is called toyo (pronounced TOH-yoh), and is usually found beside other sauces such as patis (fish sauce, pronounced pah-TEES) and suka (sugar cane vinegar, pronounced SOO-kah). The flavor of Filipino soy sauce, made from soybeans, wheat, salt, and caramel, is interestingly milder compared to its Asian counterparts--possibly an adaptation to the demands of the Filipino palate and its cuisine. It is thinner in texture and has a saltier taste compared to its Southeast Asian counterparts, much more similar to the Japanese shōyu. It is used as a staple condiment to flavor many cooked dishes and as a marinade during cooking, it is also a table condiment, and is usually mixed and served with kalamansi (a small Asian citrus-lime). Popular Philippine brands are Marca Piña, Silver Swan, Lauriat, Datu Puti, Toyomansi and UFC (Universal Food Public Company).

Hawaiian shoyu

A unique type of soy sauce produced by Aloha Shoyu Company since 1946 is a special blend of soybeans, wheat, and salt, historically common among local Hawaii residents. Hawaii residents rarely use the term "soy sauce," opting to use the Japanese loanword "shoyu" instead. However, while the Japanese word shōyu is pronounced like show you, Hawaii residents prounounce the word like shoi-yu.

18.Write a brief note on Dry Sausage Preparation.

Dry Sausage:

A sausage is a prepared food, usually made from ground meat, animal fat, salt, and spices (sometimes with other ingredients such as herbs), typically packed in a casing. Sausage making is a traditional food preservation technique.

Traditionally, casings are made of animal intestines though are now often synthetic. Some sausages are cooked during processing, and the casing may be removed after that. Sausages may be preserved by curing, drying in cool air, or smoking. When cooking sausages it is important to ensure they are pricked with a fork or similar implement first in order to prevent their disintegration and to prevent loss of flavour.

Classification of sausages

Sausages from Reunion Island

Swojska (Polish)

Krajańska (Polish)

Szynkowa (Polish)

A frankfurter sausage contains a lot of protein, yet low calories/fat (for meat)

Sausages may be classified in any number of ways, for instance by the type of meat and other ingredients they contain, or by their consistency. The most popular classification is probably by type of preparation, but even this is subject to regional differences of opinion. In the English-speaking world, the following distinction between fresh sausages, cooked sausages and dry sausages seems to be more or less accepted:

Cooked sausages are made with fresh meats and then fully cooked. They are either eaten immediately after cooking or must be refrigerated. Examples include hot dogs, Braunschweiger and liver sausages.

Cooked smoked sausages are cooked and then smoked or smoke-cooked. They are eaten hot or cold, but need to be refrigerated. Examples include Gyulai kolbász, kielbasa and Mortadella.

Fresh sausages are made from meats that have not been previously cured. They must be refrigerated and thoroughly cooked before eating. Examples include Boerewors, Italian pork sausage, breakfast sausage and Yarraque.

Fresh smoked sausages are fresh sausages that are smoked. They should be refrigerated and cooked thoroughly before eating. Examples include Mettwurst and Romanian sausage.

Dry sausages are cured sausages that are fermented and dried. They are generally eaten cold and will keep for a long time. Examples include salami, Droë wors, Sucuk, Landjäger, and summer sausage.

The distinct flavor of some sausages is due to fermentation by Lactobacillus, Pediococcus and/or Micrococcus (added as starter cultures) or natural flora during curing.

Other countries, however, use different systems of classification. Germany, for instance, which boasts more than 1200 types of sausage, distinguishes raw, cooked and pre-cooked sausages.

Raw sausages are made with raw meat and are not cooked. They are preserved by lactic acid fermentation, and may be dried, brined or smoked. Most raw sausages will keep for a long time. Examples include cervelat, mettwurst and salami.

Cooked sausages may include water and emulsifiers and are always cooked. They will not keep long. Examples include Jagdwurst and Weißwurst.

Pre-cooked sausages are made with cooked meat, and may include raw organ meat. They may be heated after casing, and will keep only for a few days. Examples include Saumagen and Blutwurst.

In Italy, the basic distinction is:

Raw sausage (salsiccia) Cured or cooked sausage (salume)

The US has a particular type called pickled sausages, commonly found in gas stations and small roadside delicatessens. These are usually smoked and/or boiled sausages of a highly processed frankfurter (hot dog) or kielbasa style plunged into a boiling brine of vinegar, salt, spices (red pepper, paprika...) and often a pink coloring, then canned in wide-mouth jars. They are available in single blister packs, e.g., Slim Jim meat snacks, or in jars atop the deli cooler. They are shelf stable, and are a frequently offered alternative to beef jerky, beef stick, and kippered beef snacks.

Certain countries classify sausage types according to the region in which the sausage was traditionally produced:

France : Montbéliard, Morteau, Strasbourg, Toulouse, Merguez... Germany : Frankfurt, Thuringia, Nuremberg, Pomerania, ...

Austria : Vienna, ...

Italy : Merano (Meran)

UK : Cumberland, Chiltern, Lincolnshire, Glamorgan ...

Slovenia : Kranjska (klobasa), after the Slovenian name for the province of Carniola

Spain : botifarra catalana, chorizo riojano, chorizo gallego, chorizo de Teror, longaniza de Aragón, morcilla de Burgos, morcilla de Ronda, morcilla extremeña, morcilla dulce canaria, llonganissa de Vic, fuet d'Olot, sobrassada mallorquina, botillo de León, llonganissa de Valencia, farinato de Salamanca, ...

Poland : kielbasa krakowska (Kraków-style), toruńska (Toruń), żywiecka (Żywiec), bydgoska (Bydgoszcz), krotoszyńska (Krotoszyn), podwawelska (literally: "from under Wawel"), zielonogórska (Zielona Góra), rzeszowska (Rzeszów), śląska (Silesia), swojska, wiejska, jałowcowa, zwyczajna, polska, krajańska, szynkowa, parówkowa ...

Hungary : kolbász gyulai (after the town of Gyula), csabai (after the city of Békéscsaba), Debrecener (after the city of Debrecen).

19.Write a brief note o Katsuobushi Preparation.

Katsuobushi:

Katsuobushi is the Japanese name for a preparation of dried, fermented, and smoked skipjack tuna (Katsuwonus pelamis, sometimes referred to as bonito). Katsuobushi and kombu (a type of kelp) are the main ingredients of dashi, a broth that forms the basis of many soups (such as miso soup) and sauces (e.g., soba no tsukejiru) in Japanese cuisine. It is today typically found in bags of small pink-brown shavings. Larger, thicker shavings, called kezurikatsuo, are used to make the ubiquitous dashi stock. Smaller, thinner shavings, called hanakatsuo, are used as a flavoring and topping for many Japanese dishes, such as okonomiyaki. Traditionally, large chunks of katsuobushi were kept at hand and shaved when needed with an instrument called a katsuobushi kezuriki, similar to a wood plane, but in the desire for convenience this form of preparation has nearly disappeared. Katsuobushi, however, retains its status as one of the primary ingredients in Japanese cooking today.

Katsuobushi's umami flavor comes from its high inosinic acid content. Traditionally made katsuobushi, known as karebushi, is deliberately planted with fungus (Aspergillus glaucus) in order to reduce moisture.

When hanakatsuo is added as a topping to a hot dish, the steam has the effect of making the flakes move as if dancing; because of this, katsuobushi topping is also known as dancing fish flakes.

Uses

Other than the main ingredient of dashi stock, other popular uses of katsuobushi include:

Okaka, finely chopped katsuobushi dressed with soy sauce. o As a stuffing for rice balls (onigiri).

o As a topping for rice. Popular for bentō, often covered with nori. A bentō with okaka and nori is called "nori-ben".

o Dried okaka is used as an indredient of furikake rice topping (called "okaka furikake").

As a seasoning for cold tofu along with grated ginger and Welsh onion (a type of spring onion.)

Sprinkled with sesame seeds and chopped nori atop cold soba noodles (zarusoba).

As a topping on takoyaki and okonomiyaki.

As a seasoning on century egg along with sesame oil and soy sauce.

As a high-protein treat for cats sold at pet stores.

Popular culture Katsuobushi was the inspiration for the title of the John Lennon album Shaved Fish. The original Iron Chef Japanese on the television show Iron Chef, Rokusaburo Michiba, was known on the show for

his trademark "broth of vigor", created from katsuobushi.

20.Write a brief note on fermented dairy products.

FERMENTED DAIRY PRODUCTS:

KEFIRIntroduction:

Kefir is the self-carbonated fermented milk product with high nutritional status and therapeutic value. It requires a special culture called kefir grains. The grain consists of casein and gelatinous colonies of microorganisms, which live, in symbiosis. The organism isolated is yeast such as Torula and Saccharomyces kefir and bacteria such as L.acidophilus,

Streptococcus lactis and L.kefiranofaciens. The yeast represents 5 – 10 % of the total micro flora. The grains are irregular in shape, yellowish in color and insoluble in water. Dried grains retain their activity for more than a year when stepped in milk the grains swell. During fermentation process Lactobacillus sp. produces lactic acid and lacto fermenting yeast cell produce alcohol

and CO2. All activities are controlled by incubation temperature.Uses:

Starter organisms produce risin, lactimine, streptocine is widely used in hospitals. It is included in diets of patients suffering from intestinal diseases, anemia, metabolic disorders, hyper toxicity, and

allergic diseases. It is beneficial for the treatment of tuberculosis. The product in diet reduces serum cholesterol level in infants.

CULTURED BUTTER MILKUses:

1) It is highly nutritious and suited as a supplement to local foods.2) Fermentation predigests several milk constituents, synthesizes water soluble vitamin of B complex and

makes a nutritionally upgraded milk.It is a fermented product made by using mesophilic starters.

Production:

Milk free from antibiotics & detergents with fat content of 0.5 – 1 % is homogenized at 150c

Heated at 900c – 13 mins & cooled to 230c.

Starter culture [Str. lactis, Str. cremoris – acid production, Str. diacetylactis, Leuconostoc citrovorum – aroma & flavor 1-2%].

Fermentation time is 16 – 20 hrs, acidity – 0.9%, mixed, cooled, bottled & stored at 50c.

Final product is viscous, drink with pleasing aroma, flavour.

KUMISS Prepared from mare milk, which is inoculated with starter culture of 10 – 20%. Cow milk or skimmed milk with 2.5% sucrose is used due to non-availability of mare milk. Microflora includes Lactobacillus delbrueckeii ssp bulgaricus, L. acidophilus, Kluveromyces lactis.

Use:

Kumiss from mare milk is a good supplementary remedy for treatment of TB.BUTTER

Introduction:

Butter is a concentrate of one of the 3 main constituents of milk ie., fat, proteins, lactose. The later 2 are present only in small proportion. Butterfat also contains the yellow coloring matter carotine and or its transformation products vitamin A and D.

Composition:

Butter and moisture 16%

Milk fat 80%

Milk solids 2%

Butter making process:

1.Preparation of cream, pasteurization, cooling and starter addition:

Cream is produced by mechanical separation of unhomogenized whole milk. Cream is pasteurized between 88 – 930

c. It may be subjected to vacuum cooling to ripening temperature of 16-210 c and ripened with 4% of mixed starter culture having;

1.acid producers like Streptococci lactis /S.cremoris.

2.flavor producers like L.mesenteroides, S.diacetylactics.

The ripening may be in 2/3 stages to produce soft, firm butter.

2. Churning, washing and salting:

The cream is loaded for churning in machines. The machine has 3 sections;

1.churning

2.separating

3.working sections

The churning section consists of a horizontal cylinder and a rotating variable speed rotator/beater [0-1000 rpm] since churning lasts for 1-2 sec it is important to adjust the beater velocity to obtain optimum butter grain size.

The separating section consists of a horizontal cylinder. The first part of the cylinder is equipped with beaters for further treatment mixtures of butter grains and butter milk which is fed from the churning sections.

The second part of the cylinder is designed as a sieve for draining buttermilk. It is equipped with wire gauze, which retains even small butter grains.

The working section consists of inclined sections for transport of the butter. In the production of salted butter, a salt slurry [40-60%] is pumped into the first working section, in which it is worked into the butter before butter proceeds to the second working section. Any adjustment of butter moisture also takes place in the first working section. Water dosing is done automatically.

Quality of wash water:

The chill water used for washing butter granules is an important source of contamination of butter. The treatment of butter with wash water has 2 purposes:

1. To wash away the free butter milk from the butter granules.2. To control the temperature of the granules for subsequent working process. The following organisms are known to

infect butter through wash water.[P.putrifaciens, P.fluorescens, P.fragi, P.methicica]Packaging:

Butter is packed either in bulk or in consumer’s size containers. Normally vegetable parchment is used to line butter boxes and also a wrapper for consumer packs. Polyethylene films replace parchment paper. Giving sodium propionate treatment can control mold growth.Flavor of butter:

The flavor of butter is produced by the fermentation of citric acid by Leuconostoc and Streptococcus lactis. Citric acid is converted into pyruvate, co2 , acetic acid. Pyruvate is again metabolized to form CO2 and acetaldehyde. Acetaldehyde under neutral and acidic conditions forms acetic acid and ethanol. Under acidic conditions these products are further metabolized into diacetyl and acetyl methyl carbinol.

Production:

Cream separation [unhomogenised whole milk] was pasteurized at 88 – 930c, cooled at 16-210c.

Starter culture was added [Strep. lactis, Strep. cremoris – acid producers, Leuconostoc mesenteroides,

Strep. diacetylactis – flavor producers].

Churning [adding colour], Draining butter milk, Washing.

Adding salt [40-60%], Working [salt enters butter], Washing

Packing & storage at 50c.

Spoilage and defects:

Many of the defects of butter originate in the cream, from which it is made especially if the cream is held for several days. During this time lactic acid bacteria and other spoilage organisms may grow which may be followed by the growth of the molds, Geotrichum candidum.Flavor defects:

The main defects developing in butter during storage are;

1. Oxidative rancidity 2. Hydrolytic rancidity 3. Putrefactive taintsGrowth of microorganisms in cream and in the milk from which it is separated may result in any of the following bad flavors.

S.no Defects Organism involved

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Acid

Barny flavor

Rancidity

Cheeseiness

Yeast

Musty

Flat

Malty

Unclean

Surface taint/rabbito/putridity

Ester like flavor

Fishiness

Metallic

Feed

Taste like cultured buttermilk due to souring of cream.

Enterobacter

Resulting from lipolytic bacteria and mold.

Lactobacillus

Flavor similar to bakers yeast results from growth of yeast in cream or butter.Produced by molds and Actinomycetes.

Lacking typical flavor Pseudomonas sp.

Produced by Streptococcus lactis

Intense old cream flavor caused by coliforms

P.putrefaciens

P. fragi

Aeromonas hydrophila

Suggestive of metal caused by metal catalyzed oxidation.

Aromatic flavor[feeds eaten by cows]

Colour defects:

1. Dark smoky discolouration Alternaria, Cladosporium2. green colouration Penicillium3. Brown colouration Alternaria4. Orange/yellow spots Geotrichum5. Dry reddish pink area Fusarium culmorum6. Pink colonies yeast

Chemical defects:

1.Rancidity lipase in cream

2.Tallowiness oxidation of unsaturated fats catalyzed by copper and bacterial enzymes and favored by low pH, T0 , salt,air, ozone.

3.Fishiness Trimethylamine is produced from lecithin.

21.Write a brief note on Cheese Production.

Cheese

Introduction:

Cheese making is a convenient way of converting fat & protein present in milk into a nutritious

product with good keeping qualities. Microorganisms play an important role in this process to provide texture & flavor to the product. It is one of earliest method of preserving milk solids. Cheese is a compressed fermented milk product.

Classification:-

Cheese can be classified into several types based on several criteria;

a. Based on the firmness of cheese. [Moisture]b. Source of milk. [Cow, buffalo]c. Ripening. [Fungi/bacteria]d. Country of origin. [eg: cheddar English, Roquefort Southeast France]e. Content of fat. [Skim milk, full cream milk]f. Manufacturing process.

The basic procedure of manufacturing is same for all types of cheese. There are 4 major steps in the

Production of cheese.

1. Control of the properties of milk.2. Coagulation3. Separation of whey & curd4. Cheese ripening

I. Control of the properties of milk:-

Good quality milk is more important for cheese making because it is not possible to pasteurize

Cheese milk intensively. The bacterial content of milk used for cheese making should be low because microorganisms growing in raw milk may develop unwanted flavour & enzyme. Some organisms survive pasteurization & cause fault in cheese. The number of psychrotrophs & thermoduric organism should be low. The physical, chemical & biological properties of the milk should be controlled.

Basic stages involved in cheese making:-

*Standardization:-

Standardization of milk is done to adjust for fat or to have a balance rate of fat & casein (1: 0.7).

*clarification:-

The clarifier is an effective alternative for filtration for the removal of extraneous matter, leucocytes & Some bacteria. It is carried out at 32- 380 c Centrifugally.

Bactofugation:- If centrifuged milk is passed through the unit the 2nd time about 90% of the remaining 10% bacteria

is removed. The sludge can be sterilized & reincorporated into the milk.

Homogenization:- Milk is homogenized at low pressure the purpose is to reduce the whey exudation from the coagulum

to make cheese whiter & make promote fat hydrolysis.

Thermization:- When raw milk must be stored for a few days using for cheese it is subjected to heat treatment 630 c

for 10-15 sec & cool to 50c prior to storing.

II. Coagulation:-

It is carried out by the use of any of the following methods:-

Use of lactic acid. Addition of bacteria like lactobacillus sp. Or addition of milk clotting enzyme rennet. Application of heat. By the addition of salt. Alteration of pH.

Among these only a few methods are applicable. The commonly used method is by the adjustment

of pH.

Coagulation by pH adjustment or Ripening of milk:-

This is achieved by heating the milk at around 30-33 0 C & adding the starter bacteria. The organisms grow using lactose as an energy source & converting it into lactic acid by a complex series of reaction by involving many different enzymes. Selected strains of lactic acid organisms are used which increase the acidity.

Functions of the starter:-

Ensures consistent acid development. Aids rennet reaction & subsequent coagulation by the developed acidity. Helps expulsion of whey from the curds. Contributes to flavor & texture of cheese during ripening. Suppresses the growth of undesirable organisms.

Microorganisms used for cheese making are;

Type Function

1. Strep. lactis Acid formation

2. Strep. cremoris Acid formation

3. Strep. diacetylactis Acid, gas & flavor production.

4. Strep. thermohiles Acid production in high scald cheese.

5. L. bulgaricus Acid production.

6. Strep. faecalis Acid & flavor in high scald cheese.

7. Propionibacterium shermanii Gas & flavor production.

Starters are used at concentration ranging from 0.5 to 2% of milk. The organism multiply during cheese making from about 10 7 CFU/ml in milk to around 10 9 cfu/gm of the curd. The growth gets checked at the salting cheese stage. All additives are added & mixed separately before rennet addition. To provide uniform colour to cheese annatto colour [alkaline extract from seeds of Bixa orelana] is added to get yellow tint. Calcium chloride at 0.01 to 0.03% of the milk is used to improve the firmness of the coagulation by rennet. The addition of 15gms of salt per 100kg of cheese milk prevents blowing (development of too much of gas in the cheese) caused by coliform bacteria or butyric acid or propionic acid bacteria.

Rennetting:-

After a mild increase in acidity of milk created by starter rennet extract is added to milk & uniformly distributed to effect coagulation of milk. The coagulation enzymes are,

Type Source of Enzymes

* Animal Calf (Chymosin or pepsin )

Pig (Pepsin)

* Bacteria B. Subtilis

B. Polymyra

B. mesenteroides

* Fungi Mucor meihei

M. pusilus

Endothica parasitica.

The enzymes act in 3 phases;

1. Primary / Enzymatic phase:-

It results in the conversion of one of the milk protein from a colloidal suspension to a fibrous network. This is done in the presence of calcium.

1. Secondary/Clotting phase:- The coagulation of the other function of enzymatic activity & coagulation can be achieved by an increase

in temperature or decrease in pH.

2. Tertiary/ Proteolytic phase:- Chymosin hydrolyze the milk protein to polypeptides. A part of polypeptides are broken down to

peptides & amino acids.

III. Separation of curd & whey:-

Separation can be done by mechanical means. Whey separation depends on temperature, pH & physical characteristics of the curd. Increased temperature enhances whey separation. Whey separating is carried out by the following methods:-

By cutting the curd & allowing the whey to flow. By placing the curd in perforated containers & allowing the whey to drain through the perforations. The curd can also be collected on a clean cloth & whey can be filtered out.

For cutting the curd, special knives are used for different sizes of cubes.

Scalding:-

High scald cheese the temperature may be 52-58 0 C, in medium scald 30-42 0 C & in low scald around 30-35 0 C. During combined action of stirring & heat, lactic acid with the curd particle is formed by the starter organisms, embedded in cheese particles & curd cubes shrinks in size. When the desired development in the curd has reached whey is drained for texturing the curd

Draining the whey:-

The curd is allowed to settle, acidity measured, when it has reached desired level, the whey is run off until the compact mass of curd is formed in the vat.

Milling:-

It helps in uniform distribution of salt (1-2%) salt acts as a preservative & flavor enhancer.

Pressing:-

The curd is filled in moulds & pressed. The degree of pressing & length of time various with the type of cheese.

Packaging & storing:-

Packaging protects flavor contamination

Entry to external molecules. Loss of moisture. Enhances appearance.

Wax coating /plastic film for hard cheese. Aluminium / plastic film for semi-hard cheese. Maturing period is 2-24 months. The cheese is stored in increased T 0 in fermentation room & shifted to ripening room

having lower temperature for the development of proteolysis, lipolysis, aroma & texture.IV . Cheese ripening:-

It refers to the changes in the body to texture accompanied by the development of characteristic flavor typical to that of cheese. Flavor & aroma is produced by the action of microorganisms & enzymes which breakdown,

Carbohydrate producing lactic acid, acetic acid, Co2 & diacetyl. H2O insoluble proteins to protease, peptons, peptides, amino acids, organic acids, NH3. Fat to lower fatty acids, their esters & Ketones.

These changes are brought about by enzymes from,

-> Lactic acid bacteria in starter culture.

-> Miscellaneous non-starter bacteria in milk.

->Rennet & its substitutions used to coagulate the milk.

->Other microorganisms growing within or surface of cheese.

The cheesy flavor is mainly due to carboxyl, nitrogenous compound, fatty acids, sulphur compounds etc.

Manufacture of Cheddar cheese.

Raw milk

Pasteurize at 71 – 750C – 15 secs [pasteurization reduces the number of spoilage organisms & lactic acid bacteria & kills most pathogens]

Cool & incubate in cheese vat at 300c [add starter culture Lactococcus lactics ssp cremoris 1 – 1.5%]

[lactic acid fermentation develops]

Milk with 0.19 to 0.21 % lactic acid [rennet added].

[curd’s formation]

Cutting of curds.

[ whey released]

Scalding 38 – 400c & stirring [acid production continues without starter culture].

Cheddaring – Squeezing & Stretching the curd [acid production continues without starter growth giving a final lactic acid concentration of 0.6 – 0.8 % - primary metabolism].

Milling and salting [ salting prevents further starter activity, assists in preservation & adds flavor & further release of whey]

Moulding & pressing [further release of whey]

Ripening

[secondary metabolism- Proteinase enzyme released from starter organism produce aminoacid , indole, sulphur compounds and phenol to enhance flavor. H2O2 and bacteriocin to inhibit pathogen and spoilage organisms]

[moisture content]

Soft cheese Semi-soft cheese Hard cheese Very hard cheese [ Very low

[50-80 %] [39-50%] [34 – 39%] moisture].

Eg: unripened cottage cheese

Ripened camembert cheese

Salt cured feta cheese

Eg: Ripened by moulds Roquefort cheese

Ripened by bacteria Brick, Gowda, Limburger

Eg: cheddar cheese

Eg: Grana, Parmesan, Asiago old.

Off flavor is produced by gas forming organisms. Eg: Clostridium, coliforms, yeasts. Gassiness is produced by Clostridium, Bacillus polymyxa [produces gas and defects in ripening cheese]. Bitter flavor is produced by coliforms, Micrococci, Yeasts [acid proteolytic bacteria]. Leuconostoc produces Holes/openness in cheddar cheese. Proteolysis, gas production is by undesirable microbes. Sliminess/Off flavor is produced by Pseudomonas fragi, Alcaligenes metaalcaligenes.2.DURING RIPENING:

Physical changes [hole formation, change nature of texture] Chemical changes [undesirable end product, metal discoloration] Gas holes/eyes/cracks/splitting [Clostridium-butyric acid+gas] Undesirable acid [Propionibacterium sp.] Bitterness [Streptococci] Acid + proteolytic [coliforms, Micrococci] Yeast flavor/sweet fruity flavor [yeast] Putrefaction [Clostridium tyrobutyricum, Cl.lentoputrescens, Cl.sporogenes] Discoloration ;

Eg: rusty spots Lactobacillus plantarum, L.brewis

Yellow/pink/brown Propionibacterium

Reddish brown to grayish brown due to oxidation of tyrosine by bacteria.

3.FINISHED CHEESE:

OOSPORA [GEOTRICHUM] Dairy mold G.lactis Red colour G.rubrum/G.crustacea Red spot G.aurianticum Cheese cancer G.caseocorans

CLADOSPORIUM [DARK/SMOKY COLOUR] Dark green to black colour C.herbarum

PENICILLIUM [GROWS IN CRACKS]

Green sporesP.puberulum Yellowish brown spot P.casei Camembert discolouration P.aurantiovirens

22.Write a brief note on Yoghurt Production.

Yoghurt [Bulgarian milk].

Yoghurt is the fermented milk product characterized by its viscous consistency, a strong acidulous taste due to high acidity [pH 4.6] and a distinct aroma caused mainly by acetaldehyde. Large-scale manufacture only started in the UK in the 1960s but

SPOILAGE OF CHEESE:1.DURING MANUFACTURING:

RAW MILK:

4.BLACK SPOT/OFF FLAVOR Monilia sp.,/M.nigra

5. DISCOLOURATION Aspergillus/Mucor/ Alternaria/ Scopulariopsis6.Yellow /red growth Brevibacterium linens

since then yoghurt has become an increasingly important dairy product with many different varieties now available in supermarkets and other retail outlets.Spoilage:

1. Bloom cartons/frothy consistency and yeasty off flavor, odour yeast ferments sugar into CO2 and ethanol.

2. Mould growth is less but spoils the surface of yoghurt particularly in under filled cartons.Prevention:

1. Sterilization of filling equipment.2. Careful storage of packaging.3. Installation of filtered air laminar and airflow facilities in filling rooms.4. Use of UV in filling areas.5. Periodic fumigation of filling rooms.6. Control of spillages.7. Use of sulphate in fruit.8. Heat treatment of final product.9. Use of preservative in the final product.10. Proper use of fruit and fruit syrups to prevent contamination.

Whole milk, Skim milk + water, Whole milk + cream

Pasteurization [850c – 30 mins batch process,90 - 950 c – 10minutes continuous ] inhibits Salmonella, Listeria, Camphylobacter.

Homogenize [60 – 650c] – smooth texture

Emulsifier’s addition [agar, gums, alginate to increase the viscosity]

Sweeteners addition [5% sugar inhibit lactic acid production].

Heat [90 – 950c] & cool

Inoculate with starter [Strep. salivarius ssp thermophilus, Lactobacillus delbreukii ssp bulgaricus]

Incubate [4 – 16 hrs at 30 – 450c] & Cool [ 10 – 150c]

Add fruit and flavor

Package [Maintain at chill temperature at 4.50c – 2 wks].

Recently, a different type of yoghurt has been produced that uses a mixture of;

L.acidophilus+Bifidobacterium bifidum AB yoghurt

L.acidophilus+Bifidobacterium bifidum+S.salivarius thermophilus ABT yoghurt

These bio or therapeutic yoghurt are said to have health promoting properties. Manufacture of this type of yoghurt involves direct vat inoculation with the starter followed by incubation at 370 c for about 16 hrs giving a final product with a pH of 4.2 to 4.4 and a milder creamier flavor.

Nutritive value of yoghurt:

During fermentation of milk the composition of minerals remain unchanged while proteins, carbohydrates, vitamins and fats to some extent are subjected to changes. The substances formed are lactic acid, alcohol, CO2 ,antibiotics and vitamins. The following processes make yoghurt

1.Proteolysis:

Proteolysis in milk takes place by exopeptidases and endopeptidases of lactic acid bacteria. So biological value increases 85.4 to 90%. This increases due to breakdown of proteins into peptides,

amino acids. The contents of essential amino acid such as leucine, isoleucine, methionine, phenyl alanine, tyrosine, tryptophan and valine increases which offers special advantage.2.Hydrolysis of lactose:

Lactose in milk is hydrolysed by metabolic activity of bacteria. Lactic acid inhibits the growth of putrifactants. It is important for organolectic properties and calcium absorption.

3.Lipolysis:

The homogenization process reduces the size of globules which become digestible, as a result of lipolytic activity the free fatty acid increases, which have some physiological effect.

4.Changes in vitamins:

There is more than 2 fold increase in vitamins of B group especially thiamine, riboflavin and nicotinamide.

5. Antibacterial activities:

The antibiotic properties are associated with Lactobacilli in yoghurt and materials responsible are lactic acid, H2O2 and lactobacilline.6.Therapeutic properties:

1. Easy absorption and better assimilation. Eg; milk [32% in 1 hr], yoghurt [91% in 1 hr].2. Improves appetite due to its pleasant refreshing and pungent taste. It is highly nourishing invigorating.3. Gastric juice secreted by the action of yoghurt and desirable ratio of calcium and phosphorous induced by it leads to a

high digestive capacity.4. Removes excessive fat from liver and enhances bile secretion. It has therapeutic importance in GI disturbances

hepatitis, nephritis, diarrhea, colitis, anemia, and anorexia.

5. It provides relief to chronic diarrhea in spruce and ulcerative colitis. Fat free yoghurt is importance to those who suffer from heart diseases.

6. Yoghurt possesses potent anti-tumour activity. Pathogenic bacteria are not able to survive due to low pH.

23.Write a brief note on Saurkraut Production.

Fermented Vegetables Sauerkraut

The sauerkraut fermentation is an example of a microbial succession. Microbial succession involves the growth of a group or species of micro organisms in an environment, the conditions of which then change as a result of their activities so that another group or species is favoured and becomes dominant. The microbial succession involved in the fermentation of sauerkraut can pass through 3 phases.Phase 1:

1. Leuconostoc mesenteroides initiates the fermentation. The organism is heterofermentative, converting sugars in the brine into lactic acid, acetic acid, ethanol and Co2.Sugars L.mesenteroides L.A + A.A + Ethanol + Co2

2. The role of this organism in the fermentation is complex and fundamental to the production of good quality sauerkraut.a. Rapid reduction of pH [below 4.0] within 2 days due to fermentation of lactic and acetic acids. This reduces

and inhibits the bacteria other than lactic acid bacteria that may cause the cabbage to putrefy and enzymes that may cause the cabbage to soften.

b. Co2 production helps to purge O2, from the brine. This creates an anaerobic condition which is important in restricting the growth of organisms other than lactic acid bacteria. Co2 will also inhibit the growth of some G-ve bacteria and stimulate the growth of other lactic acid bacteria that form part of the fermentation flora.

c. The anaerobic conditions produced stabilize vitamin C in the cabbage so that a large percentage of the vitamin present in the raw material is retained.

d. Reducing sugars produced from the breakdown of excess sucrose in the brine can cause the product to darken by combining with amino acids present [Maillard Browning] Leuconostoc prevents this process by converting fructose to mannitol and glucose to dextran. Both are available as a carbohydrate source to other lactic acid bacteria and although the dextran produces a slime, this is only temporary.

e. Leuconostoc may produce growth factors that help to stimulate the growth of more fastidious lactic acid bacteria.

f. Leuconostoc contributes in a major way to the final flavour and aroma of the finished product.Early in this phase [the 1st 15 hrs] there is also some growth of gram-negative organisms. These organisms, mainly coliforms, help to remove oxygen from the brine and disappear within a day or two.Phase II:

As lactic acid accumulates in the brine and the pH drops, the more acid-tolerant Lactobacillus brevis and Lactobacillus plantarum start to increase in numbers. Both organisms produce lactic acid [L.brevis is heterofermentative and L.plantarum is homofermentative] and after about 6-8 days become the dominant flora.Phase III:

After about 16-18 days the numbers of L.brevis decline and the population becomes dominated by L.plantarum. The organism continues to ferment any residual sugars to produce lactic acid and a fully stable product in which all the sugars have been fermented.

The final sauerkraut has a stable pH of 3.8 and contains 1.7 to 2.3% acid [calculated as lactic acid] with a ratio of acetic : lactic acid of about 1 : 4. Diacetyl, acetaldehyde and a number of esters have been identified in the final product, which contribute to its characteristic odour and flavour.Microbiological Problems:

1. High Temperature:

At high temperatures of 32 C and above growth of Leuconostoc mensenteroides is prevented and the population becomes dominated by Lactobacillus plantarum and pediococcus pentosaceous. Both organisms are homofermentative, their growth resulting in product that darknes readily and has a poor flavour.2. Aerobic conditions:

Aerobic conditions produced when the fermenting cabbage is not covered properly or air pockets are allowed to form when the cabbage is packed into vats, will allow the growth of yeasts and moulds. Discolourations E.g., the pink colour is due to growth of the yeast Rhodotorula, off flavours [yeasty or mouldy flavour] and softening due to pectinolytic activity of moulds are resulting defects.3. Uneven or Low salt Concentrations:

Uneven or low salt concentrations may allow putrefactive bacteria to grow, resulting in a spoiled product.Sauerkraut Defects and Spoilage:

Sauerkraut may be inferior quality because of abnormal fermentation and excessively high T inhibits the growth of Leuconostoc and consequently the flavour production. It may permit the growth of pediococcus cerevisiae and development of undesirable flavours. Low T may prevent lactic bacteria and encourages the growth of containments from soil. E.g., Enterobacter and flavobacterium. The long fermentation may favour the growth of L.brevis which yields a sharply acid flavour. Too much salt may encourage Pediococcus and Yeast. Abnormal fermentation of cabbage may result in cheese like odour caused by propionic butyric, caproic and valeric acid along with isobutyric and isovaleric acid.

1. Soft Kraut:

It may result from a faulty fermentation and from exposure to air or excessive pressing and / or tamping.2. Dark Brown / Black Kraut:

It is due to oxidation during exposure to air and is caused by combined action of plant enzyme and microorganisms destruction of acid by film yeast and molds make cardition favourable for proteolytic and pectolylic microorganisms to rot the kraut. Darkening is encouraged by uneven salting and high T. Brown colour may result from iron in hoops and tanning from barrels.3. Pink Kraut:

It is caused by red asporogenous yeast in the presence of air and high salt that has been distributed unevenly. The development of pink colour is favoured by high T, dirty vats, low acidity and iron salts.4. Ropy Krauts / Slimy Krauts:

It is caused by encapsulated varieties of L.plantarum. The sliminess may disappear on longer holding and cooking of the kraut.

Sauerkraut is subjected to spoilage at its surface, where it is exposed to air. Film yeasts and molds destroy the acidity permitting other microorganisms to grow and cause softening.

5. Salt Burn:

If salt concentration increases the surface may be darken to black. [high salt and high T]

PICKLESCucumber pickles may be prepared without fermentation or partial or complete fermentation. They can be pasteurized

to improve their keeping quality. Brined acidified cucumbers are heated so that the interior of the cucumber will be maintained at 73.9 C for atleast 15 min. Both heating and cooling should be rapid. These are 2 chief types of fermented pickles;

a. Salt or salt stock pickles b. Dill pickles.I. Preparation of Salt or Salt Stock Pickles: Immature cucumber are washed, placed in barrels or tanks and brined. Sometimes about 1% of glucose is added if the cucumbers are low in sugar. The addition of sugar will favour the production of gassy pickles or bloaters.Addition of Salt:

The rate of addition of salt and total amount added varies considerably 2 methods of salting, low salt method and high salt method.

High salt method 50 salometer [10.5% NaCl] and final 60 salometer [15% NaCl]Low salt method 30 salometer [8% NaCl] and final 45 salometer

The cucumbers are keyed down under a surface layer of brine and fermentation begins. In both methods salt is added at weakly intervals to increase the salometer reading by about 3 salometer up to 60. In the low salt method the increase is about 2 per week up to 50. In warm climates the salt content of brine may be increased more rapidly and cool climates a weaker brine may be added initially.1. The Traditional Fermentation:

The traditional process usually takes 6-9 weeks for completion, depending on he salting method and T employed. The number of salt tolerant sp. Of bacteria may grow initially in the newly brined fresh cucumbers. These may be marked difference in the kinds of bacteria growing in different lots, depending on the number of and kinds introduced by the cucumbers or dirt left on them and by the water of the brine, initial concentration of sodium chloride and rate of increase, and the T of the brined cucumbers. Low salt concentration will favour more kinds of bacteria, faster the acid production and greater the acidity. First to grow is Pseudomonas and Flavobacterium, types considered undesirable. Bacillus sp are likely to come on from the soils on the cucumber and their growth is undesirable. In brines of low salt content coliform bacteria, Leuconostoc mesenteroides, str. Faecatis, Pediococcus cerevisiae may grow and form acid and in 15% brines gas forming cocci may produce some acid. Later

L.brevis may contribute to acidity if the salt concentration is not too high. L.plantarum developes acidity in both low and high salt brines. It becomes decreasingly active as the salt concentation increased. The total lactic acid content is 0.6 to 0.8%. Heterofermentative lactics yield pickles that are firm and have better density than homofermentative lactics.

Yeast may grow after some acid has been formed by the bacteria. Two types,1. Film / Oxidative yeast:

Which grows on the surface of the brine and destroy lactic acid by oxidation. E.g., Debaryomyces, Endomycopsis, Candida.

The control includes daily agitation of the surface or the addition of the mineral oil, sorbic acid or other substances. Pickle vats are located out in the sunlight which inhibits surface growth on the brine.2. Fermentative Yeast:

Which grows down in the brine and ferment sugar to alcohol and Co2. E.g., Torulopsis, Zygosaccharomyces, Hansenula. Gas produced by these yeast, bubbles from the brine and may be responsible for bloated pickles.

When the cucumber are first brined they are chalky white and opaque but during the fermentation and cure the colour changes from bright green to yellowish green and the flesh becomes increasingly translucent. The salt pickles are prepared for use in making special products such as sour, sweet sour, mixed pickles, relishes or other products.2. The controlled fermentation:

This process is designed to eliminate or minimize the defects of the traditional fermentation. First the cucumbers are washed, brined and sanitized [cl – 80 ppm] in the vat. The chlorimated brine is then acidified with glacial acetic acid. These 2 process suppers the growth of undesired bacteria. Following a purge with N2, sodium acetate is added [0.5%] to buffer the brine. This ensures effective utilization of all the fermentable carbohydrate present. After 10-24 hrs they are inoculated with special cultures of pediococcus cerevisiae and L.plantarum. During the active fermentation [10-14 days] N2 purges are repeated and additional salt is added to maintain 25 salometer.II Preparation of Dill pickles:

1. They are named because of the addition of dill herb and spices.2. They may be unfermented or fermented or made from salt stock.3. The fermentation to produce dill pickles have a lower concentration of salt and brine is acidified with vinegar at the

start. The low salt content favours and increased rate of acid production, but adds to the risk of undesirable microbial changes. The flavouring materials dill, spices, garlic etc., also act as a source of undesirable micro organisms treated spices containing low micro organisms are available 2 types of fermented dill pickles

a. Overnight b. GenuineS.No. Overnight Genuine

1

23456

Slow acid fermentation [20 sal]

Weak acidified brineCured weed of dill addedLactic acid 0.3 to 0.6%Salt concn 5.3%Kept in cold

Org L.mesenteroides Str.faecalis, P.cerevisiae, L.plantarumVinegar addedT 15-30 CAcid 1-1.5%Salt concn initial 7.5 to 8.5%Final concn 3.4 to 4.5%

Defects and Spoilage:Fermented pickles are subjected to a number of defects most of which are caused by bacteria.

1. Hollow Pickles:If cucumbers are allowed to stand for a while after harvesting and before fermenting or it may be due to loose packing

in vat, insufficient weighting, too rapid a fermentation and too strong or too weak a brine cause hollow pickles.2. Floaters or Bloaters:

It may result from gas being formed by yeast, L.plantarum or coliform which can produce Co2. This can be controlled by purging the brine with N2 to remove dissolved Co2. Floaters are favoured by thick skin that doesnot allow gas to diffuse out, by rapid gas production during fermentation, high initial salt by added sugar or / and acid.3. Slippery pickles:

It occurs when cucumbers are exposed to air permitting the growth of encapsulated bacteria. Slipperiness also may be due to broken scums of film yeast that have grown on the surface of the brine and dropped on to the cucumber.4. Soft Pickles:

They are made so by pectolytic enzymes mostly from molds and from cucumber flowers. These molds are mostly of the general Penicillium, Fusarium, Cladosporium, Alternaria.

Bacteria Bacillus, Aeromonas, Coliforms.These can degrade;

Pectinase PectinPectin Esterase Pectinic acidPoly methyl galacturnose Galactournoic acid

Softening is favoured by;a. An insufficient amount of salt. b. Too high a Tc. Low acidity

a. Presence of air favouring the growth of film yeast or mold.b. Infusions of may blossoms.

5. Black Pickles:May owe their colour due to the formation of H2S by bacteria and combination with iron in the water to yield black

ferrous sulfide. It is also due to the growth of black pigmented Bacillus nigrificans and B.subtilis.i.e., Iron Water

Sulphide From Vat / H2O / CaCo3 [Gypsum]6. Ropy Pickle Brine:

Favoured by unidentified motile, Gram –ve encapsulated rods. Favoured by

i. Low saltii. Low acid

iii. High

FERMENTED DAIRY PRODUCTS:

KEFIRIntroduction:

Kefir is the self-carbonated fermented milk product with high nutritional status and therapeutic value. It requires a special culture called kefir grains. The grain consists of casein and gelatinous colonies of microorganisms, which live, in symbiosis. The organism isolated is yeast such as Torula and Saccharomyces kefir and bacteria such as L.acidophilus,

Streptococcus lactis and L.kefiranofaciens. The yeast represents 5 – 10 % of the total micro flora. The grains are irregular in shape, yellowish in color and insoluble in water. Dried grains retain their activity for more than a year when stepped in milk the grains swell. During fermentation process Lactobacillus sp. produces lactic acid and lacto fermenting yeast cell produce alcohol

and CO2. All activities are controlled by incubation temperature.Uses:

Starter organisms produce risin, lactimine, streptocine is widely used in hospitals. It is included in diets of patients suffering from intestinal diseases, anemia, metabolic disorders, hyper toxicity, and

allergic diseases. It is beneficial for the treatment of tuberculosis. The product in diet reduces serum cholesterol level in infants.

CULTURED BUTTER MILKUses:

3) It is highly nutritious and suited as a supplement to local foods.4) Fermentation predigests several milk constituents, synthesizes water soluble vitamin of B complex and

makes a nutritionally upgraded milk.It is a fermented product made by using mesophilic starters.

Production:

Milk free from antibiotics & detergents with fat content of 0.5 – 1 % is homogenized at 150c

Heated at 900c – 13 mins & cooled to 230c.

Starter culture [Str. lactis, Str. cremoris – acid production, Str. diacetylactis, Leuconostoc citrovorum – aroma & flavor 1-2%].

Fermentation time is 16 – 20 hrs, acidity – 0.9%, mixed, cooled, bottled & stored at 50c.

Final product is viscous, drink with pleasing aroma, flavour.

KUMISS Prepared from mare milk, which is inoculated with starter culture of 10 – 20%. Cow milk or skimmed milk with 2.5% sucrose is used due to non-availability of mare milk. Microflora includes Lactobacillus delbrueckeii ssp bulgaricus, L. acidophilus, Kluveromyces lactis.

Use:

Kumiss from mare milk is a good supplementary remedy for treatment of TB.BUTTER

Introduction:

Butter is a concentrate of one of the 3 main constituents of milk ie., fat, proteins, lactose. The later 2 are present only in small proportion. Butterfat also contains the yellow coloring matter carotine and or its transformation products vitamin A and D.

Composition:

Butter and moisture 16%

Milk fat 80%

Milk solids 2%

Butter making process:

1.Preparation of cream, pasteurization, cooling and starter addition:

Cream is produced by mechanical separation of unhomogenized whole milk. Cream is pasteurized between 88 – 930

c. It may be subjected to vacuum cooling to ripening temperature of 16-210 c and ripened with 4% of mixed starter culture having;

1.acid producers like Streptococci lactis /S.cremoris.

2.flavor producers like L.mesenteroides, S.diacetylactics.

The ripening may be in 2/3 stages to produce soft, firm butter.

2. Churning, washing and salting:

The cream is loaded for churning in machines. The machine has 3 sections;

1.churning

2.separating

3.working sections

The churning section consists of a horizontal cylinder and a rotating variable speed rotator/beater [0-1000 rpm] since churning lasts for 1-2 sec it is important to adjust the beater velocity to obtain optimum butter grain size.

The separating section consists of a horizontal cylinder. The first part of the cylinder is equipped with beaters for further treatment mixtures of butter grains and butter milk which is fed from the churning sections.

The second part of the cylinder is designed as a sieve for draining buttermilk. It is equipped with wire gauze, which retains even small butter grains.

The working section consists of inclined sections for transport of the butter. In the production of salted butter, a salt slurry [40-60%] is pumped into the first working section, in which it is worked into the butter before butter proceeds to the second working section. Any adjustment of butter moisture also takes place in the first working section. Water dosing is done automatically.

Quality of wash water:

The chill water used for washing butter granules is an important source of contamination of butter. The treatment of butter with wash water has 2 purposes:

3. To wash away the free butter milk from the butter granules.4. To control the temperature of the granules for subsequent working process. The following organisms are known to

infect butter through wash water.[P.putrifaciens, P.fluorescens, P.fragi, P.methicica]Packaging:

Butter is packed either in bulk or in consumer’s size containers. Normally vegetable parchment is used to line butter boxes and also a wrapper for consumer packs. Polyethylene films replace parchment paper. Giving sodium propionate treatment can control mold growth.Flavor of butter:

The flavor of butter is produced by the fermentation of citric acid by Leuconostoc and Streptococcus lactis. Citric acid is converted into pyruvate, co2 , acetic acid. Pyruvate is again metabolized to form CO2 and acetaldehyde. Acetaldehyde under neutral and acidic conditions forms acetic acid and ethanol. Under acidic conditions these products are further metabolized into diacetyl and acetyl methyl carbinol.

Production:

Cream separation [unhomogenised whole milk] was pasteurized at 88 – 930c, cooled at 16-210c.

Starter culture was added [Strep. lactis, Strep. cremoris – acid producers, Leuconostoc mesenteroides,

Strep. diacetylactis – flavor producers].

Churning [adding colour], Draining butter milk, Washing.

Adding salt [40-60%], Working [salt enters butter], Washing

Packing & storage at 50c.

Spoilage and defects:

Many of the defects of butter originate in the cream, from which it is made especially if the cream is held for several days. During this time lactic acid bacteria and other spoilage organisms may grow which may be followed by the growth of the molds, Geotrichum candidum.Flavor defects:

The main defects developing in butter during storage are;

2. Oxidative rancidity 2. Hydrolytic rancidity 3. Putrefactive taintsGrowth of microorganisms in cream and in the milk from which it is separated may result in any of the following bad flavors.

S.no Defects Organism involved

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Acid

Barny flavor

Rancidity

Cheeseiness

Yeast

Musty

Flat

Malty

Unclean

Surface taint/rabbito/putridity

Ester like flavor

Fishiness

Metallic

Feed

Taste like cultured buttermilk due to souring of cream.

Enterobacter

Resulting from lipolytic bacteria and mold.

Lactobacillus

Flavor similar to bakers yeast results from growth of yeast in cream or butter.Produced by molds and Actinomycetes.

Lacking typical flavor Pseudomonas sp.

Produced by Streptococcus lactis

Intense old cream flavor caused by coliforms

P.putrefaciens

P. fragi

Aeromonas hydrophila

Suggestive of metal caused by metal catalyzed oxidation.

Aromatic flavor[feeds eaten by cows]

Colour defects:

7. Dark smoky discolouration Alternaria, Cladosporium8. green colouration Penicillium9. Brown colouration Alternaria10. Orange/yellow spots Geotrichum11. Dry reddish pink area Fusarium culmorum12. Pink colonies yeast

Chemical defects:

1.Rancidity lipase in cream

2.Tallowiness oxidation of unsaturated fats catalyzed by copper and bacterial enzymes and favored by low pH, T0 , salt,air, ozone.

3.Fishiness Trimethylamine is produced from lecithin.

Cheese

Introduction:

Cheese making is a convenient way of converting fat & protein present in milk into a nutritious

product with good keeping qualities. Microorganisms play an important role in this process to provide texture & flavor to the product. It is one of earliest method of preserving milk solids. Cheese is a compressed fermented milk product.

Classification:-

Cheese can be classified into several types based on several criteria;

g. Based on the firmness of cheese. [Moisture]h. Source of milk. [Cow, buffalo]i. Ripening. [Fungi/bacteria]j. Country of origin. [eg: cheddar English, Roquefort Southeast France]k. Content of fat. [Skim milk, full cream milk]l. Manufacturing process.

The basic procedure of manufacturing is same for all types of cheese. There are 4 major steps in the

Production of cheese.

5. Control of the properties of milk.6. Coagulation7. Separation of whey & curd8. Cheese ripening

I. Control of the properties of milk:-

Good quality milk is more important for cheese making because it is not possible to pasteurize

Cheese milk intensively. The bacterial content of milk used for cheese making should be low because microorganisms growing in raw milk may develop unwanted flavour & enzyme. Some organisms survive pasteurization & cause fault in cheese. The number of psychrotrophs & thermoduric organism should be low. The physical, chemical & biological properties of the milk should be controlled.

Basic stages involved in cheese making:-

*Standardization:-

Standardization of milk is done to adjust for fat or to have a balance rate of fat & casein (1: 0.7).

*clarification:-

The clarifier is an effective alternative for filtration for the removal of extraneous matter, leucocytes & Some bacteria. It is carried out at 32- 380 c Centrifugally.

Bactofugation:- If centrifuged milk is passed through the unit the 2nd time about 90% of the remaining 10% bacteria

is removed. The sludge can be sterilized & reincorporated into the milk.

Homogenization:- Milk is homogenized at low pressure the purpose is to reduce the whey exudation from the coagulum

to make cheese whiter & make promote fat hydrolysis.

Thermization:- When raw milk must be stored for a few days using for cheese it is subjected to heat treatment 630 c

for 10-15 sec & cool to 50c prior to storing.

II. Coagulation:-

It is carried out by the use of any of the following methods:-

Use of lactic acid. Addition of bacteria like lactobacillus sp. Or addition of milk clotting enzyme rennet. Application of heat. By the addition of salt. Alteration of pH.

Among these only a few methods are applicable. The commonly used method is by the adjustment

of pH.

Coagulation by pH adjustment or Ripening of milk:-

This is achieved by heating the milk at around 30-33 0 C & adding the starter bacteria. The organisms grow using lactose as an energy source & converting it into lactic acid by a complex series of reaction by involving many different enzymes. Selected strains of lactic acid organisms are used which increase the acidity.

Functions of the starter:-

Ensures consistent acid development. Aids rennet reaction & subsequent coagulation by the developed acidity. Helps expulsion of whey from the curds. Contributes to flavor & texture of cheese during ripening. Suppresses the growth of undesirable organisms.

Microorganisms used for cheese making are;

Type Function

1. Strep. lactis Acid formation

2. Strep. cremoris Acid formation

3. Strep. diacetylactis Acid, gas & flavor production.

4. Strep. thermohiles Acid production in high scald cheese.

5. L. bulgaricus Acid production.

6. Strep. faecalis Acid & flavor in high scald cheese.

7. Propionibacterium shermanii Gas & flavor production.

Starters are used at concentration ranging from 0.5 to 2% of milk. The organism multiply during cheese making from about 10 7 CFU/ml in milk to around 10 9 cfu/gm of the curd. The growth gets checked at the salting cheese stage. All additives are added & mixed separately before rennet addition. To provide uniform colour to cheese annatto colour [alkaline extract from seeds of Bixa orelana] is added to get yellow tint. Calcium chloride at 0.01 to 0.03% of the milk is used to improve the firmness of the coagulation by rennet. The addition of 15gms of salt per 100kg of cheese milk prevents blowing (development of too much of gas in the cheese) caused by coliform bacteria or butyric acid or propionic acid bacteria.

Rennetting:-

After a mild increase in acidity of milk created by starter rennet extract is added to milk & uniformly distributed to effect coagulation of milk. The coagulation enzymes are,

Type Source of Enzymes

* Animal Calf (Chymosin or pepsin )

Pig (Pepsin)

* Bacteria B. Subtilis

B. Polymyra

B. mesenteroides

* Fungi Mucor meihei

M. pusilus

Endothica parasitica.

The enzymes act in 3 phases;

1. Primary / Enzymatic phase:-

It results in the conversion of one of the milk protein from a colloidal suspension to a fibrous network. This is done in the presence of calcium.

3. Secondary/Clotting phase:- The coagulation of the other function of enzymatic activity & coagulation can be achieved by an increase

in temperature or decrease in pH.

4. Tertiary/ Proteolytic phase:- Chymosin hydrolyze the milk protein to polypeptides. A part of polypeptides are broken down to

peptides & amino acids.

III. Separation of curd & whey:-

Separation can be done by mechanical means. Whey separation depends on temperature, pH & physical characteristics of the curd. Increased temperature enhances whey separation. Whey separating is carried out by the following methods:-

By cutting the curd & allowing the whey to flow. By placing the curd in perforated containers & allowing the whey to drain through the perforations. The curd can also be collected on a clean cloth & whey can be filtered out.

For cutting the curd, special knives are used for different sizes of cubes.

Scalding:-

High scald cheese the temperature may be 52-58 0 C, in medium scald 30-42 0 C & in low scald around 30-35 0 C. During combined action of stirring & heat, lactic acid with the curd particle is formed by the starter organisms, embedded in cheese particles & curd cubes shrinks in size. When the desired development in the curd has reached whey is drained for texturing the curd

Draining the whey:-

The curd is allowed to settle, acidity measured, when it has reached desired level, the whey is run off until the compact mass of curd is formed in the vat.

Milling:-

It helps in uniform distribution of salt (1-2%) salt acts as a preservative & flavor enhancer.

Pressing:-

The curd is filled in moulds & pressed. The degree of pressing & length of time various with the type of cheese.

Packaging & storing:-

Packaging protects flavor contamination

Entry to external molecules. Loss of moisture. Enhances appearance.

Wax coating /plastic film for hard cheese. Aluminium / plastic film for semi-hard cheese. Maturing period is 2-24 months. The cheese is stored in increased T 0 in fermentation room & shifted to ripening room

having lower temperature for the development of proteolysis, lipolysis, aroma & texture.IV . Cheese ripening:-

It refers to the changes in the body to texture accompanied by the development of characteristic flavor typical to that of cheese. Flavor & aroma is produced by the action of microorganisms & enzymes which breakdown,

Carbohydrate producing lactic acid, acetic acid, Co2 & diacetyl. H2O insoluble proteins to protease, peptons, peptides, amino acids, organic acids, NH3. Fat to lower fatty acids, their esters & Ketones.

These changes are brought about by enzymes from,

-> Lactic acid bacteria in starter culture.

-> Miscellaneous non-starter bacteria in milk.

->Rennet & its substitutions used to coagulate the milk.

->Other microorganisms growing within or surface of cheese.

The cheesy flavor is mainly due to carboxyl, nitrogenous compound, fatty acids, sulphur compounds etc.

Manufacture of Cheddar cheese.

Raw milk

Pasteurize at 71 – 750C – 15 secs [pasteurization reduces the number of spoilage organisms & lactic acid bacteria & kills most pathogens]

Cool & incubate in cheese vat at 300c [add starter culture Lactococcus lactics ssp cremoris 1 – 1.5%]

[lactic acid fermentation develops]

Milk with 0.19 to 0.21 % lactic acid [rennet added].

[curd’s formation]

Cutting of curds.

[ whey released]

Scalding 38 – 400c & stirring [acid production continues without starter culture].

Cheddaring – Squeezing & Stretching the curd [acid production continues without starter growth giving a final lactic acid concentration of 0.6 – 0.8 % - primary metabolism].

Milling and salting [ salting prevents further starter activity, assists in preservation & adds flavor & further release of whey]

Moulding & pressing [further release of whey]

Ripening

[secondary metabolism- Proteinase enzyme released from starter organism produce aminoacid , indole, sulphur compounds and phenol to enhance flavor. H2O2 and bacteriocin to inhibit pathogen and spoilage organisms]

[moisture content]

Soft cheese Semi-soft cheese Hard cheese Very hard cheese [ Very low

[50-80 %] [39-50%] [34 – 39%] moisture].

Eg: unripened cottage cheese

Ripened camembert cheese

Salt cured feta cheese

Eg: Ripened by moulds Roquefort cheese

Ripened by bacteria Brick, Gowda, Limburger

Eg: cheddar cheese

Eg: Grana, Parmesan, Asiago old.

Off flavor is produced by gas forming organisms. Eg: Clostridium, coliforms, yeasts. Gassiness is produced by Clostridium, Bacillus polymyxa [produces gas and defects in ripening cheese]. Bitter flavor is produced by coliforms, Micrococci, Yeasts [acid proteolytic bacteria]. Leuconostoc produces Holes/openness in cheddar cheese.

SPOILAGE OF CHEESE:1.DURING MANUFACTURING:

RAW MILK:

Proteolysis, gas production is by undesirable microbes. Sliminess/Off flavor is produced by Pseudomonas fragi, Alcaligenes metaalcaligenes.2.DURING RIPENING:

Physical changes [hole formation, change nature of texture] Chemical changes [undesirable end product, metal discoloration] Gas holes/eyes/cracks/splitting [Clostridium-butyric acid+gas] Undesirable acid [Propionibacterium sp.] Bitterness [Streptococci] Acid + proteolytic [coliforms, Micrococci] Yeast flavor/sweet fruity flavor [yeast] Putrefaction [Clostridium tyrobutyricum, Cl.lentoputrescens, Cl.sporogenes] Discoloration ;

Eg: rusty spots Lactobacillus plantarum, L.brewis

Yellow/pink/brown Propionibacterium

Reddish brown to grayish brown due to oxidation of tyrosine by bacteria.

3.FINISHED CHEESE:

OOSPORA [GEOTRICHUM] Dairy mold G.lactis Red colour G.rubrum/G.crustacea Red spot G.aurianticum Cheese cancer G.caseocorans

CLADOSPORIUM [DARK/SMOKY COLOUR] Dark green to black colour C.herbarum

PENICILLIUM [GROWS IN CRACKS]

Green sporesP.puberulum Yellowish brown spot P.casei Camembert discolouration P.aurantiovirens

Yoghurt [Bulgarian milk].

Yoghurt is the fermented milk product characterized by its viscous consistency, a strong acidulous taste due to high acidity [pH 4.6] and a distinct aroma caused mainly by acetaldehyde. Large-scale manufacture only started in the UK in the 1960s but since then yoghurt has become an increasingly important dairy product with many different varieties now available in supermarkets and other retail outlets.Spoilage:

1. Bloom cartons/frothy consistency and yeasty off flavor, odour yeast ferments sugar into CO2 and ethanol.

2. Mould growth is less but spoils the surface of yoghurt particularly in under filled cartons.Prevention:

11. Sterilization of filling equipment.12. Careful storage of packaging.13. Installation of filtered air laminar and airflow facilities in filling rooms.14. Use of UV in filling areas.15. Periodic fumigation of filling rooms.16. Control of spillages.17. Use of sulphate in fruit.18. Heat treatment of final product.19. Use of preservative in the final product.20. Proper use of fruit and fruit syrups to prevent contamination.

Whole milk, Skim milk + water, Whole milk + cream

4.BLACK SPOT/OFF FLAVOR Monilia sp.,/M.nigra

5. DISCOLOURATION Aspergillus/Mucor/ Alternaria/ Scopulariopsis6.Yellow /red growth Brevibacterium linens

Pasteurization [850c – 30 mins batch process,90 - 950 c – 10minutes continuous ] inhibits Salmonella, Listeria, Camphylobacter.

Homogenize [60 – 650c] – smooth texture

Emulsifier’s addition [agar, gums, alginate to increase the viscosity]

Sweeteners addition [5% sugar inhibit lactic acid production].

Heat [90 – 950c] & cool

Inoculate with starter [Strep. salivarius ssp thermophilus, Lactobacillus delbreukii ssp bulgaricus]

Incubate [4 – 16 hrs at 30 – 450c] & Cool [ 10 – 150c]

Add fruit and flavor

Package [Maintain at chill temperature at 4.50c – 2 wks].

Recently, a different type of yoghurt has been produced that uses a mixture of;

L.acidophilus+Bifidobacterium bifidum AB yoghurt

L.acidophilus+Bifidobacterium bifidum+S.salivarius thermophilus ABT yoghurt

These bio or therapeutic yoghurt are said to have health promoting properties. Manufacture of this type of yoghurt involves direct vat inoculation with the starter followed by incubation at 370 c for about 16 hrs giving a final product with a pH of 4.2 to 4.4 and a milder creamier flavor.

Nutritive value of yoghurt:

During fermentation of milk the composition of minerals remain unchanged while proteins, carbohydrates, vitamins and fats to some extent are subjected to changes. The substances formed are lactic acid, alcohol, CO2 ,antibiotics and vitamins. The following processes make yoghurt

1.Proteolysis:

Proteolysis in milk takes place by exopeptidases and endopeptidases of lactic acid bacteria. So biological value increases 85.4 to 90%. This increases due to breakdown of proteins into peptides,

amino acids. The contents of essential amino acid such as leucine, isoleucine, methionine, phenyl alanine, tyrosine, tryptophan and valine increases which offers special advantage.2.Hydrolysis of lactose:

Lactose in milk is hydrolysed by metabolic activity of bacteria. Lactic acid inhibits the growth of putrifactants. It is important for organolectic properties and calcium absorption.

3.Lipolysis:

The homogenization process reduces the size of globules which become digestible, as a result of lipolytic activity the free fatty acid increases, which have some physiological effect.

4.Changes in vitamins:

There is more than 2 fold increase in vitamins of B group especially thiamine, riboflavin and nicotinamide.

5. Antibacterial activities:

The antibiotic properties are associated with Lactobacilli in yoghurt and materials responsible are lactic acid, H2O2 and lactobacilline.6.Therapeutic properties:

7. Easy absorption and better assimilation. Eg; milk [32% in 1 hr], yoghurt [91% in 1 hr].8. Improves appetite due to its pleasant refreshing and pungent taste. It is highly nourishing invigorating.9. Gastric juice secreted by the action of yoghurt and desirable ratio of calcium and phosphorous induced by it leads to a

high digestive capacity.10. Removes excessive fat from liver and enhances bile secretion. It has therapeutic importance in GI disturbances

hepatitis, nephritis, diarrhea, colitis, anemia, and anorexia.11. It provides relief to chronic diarrhea in spruce and ulcerative colitis. Fat free yoghurt is importance to those who suffer

from heart diseases.12. Yoghurt possesses potent anti-tumour activity. Pathogenic bacteria are not able to survive due to low pH.

24. Write a brief note onTarhana Production.

Tarhana (Turkish), tarkhina, tarkhana, tarkhwana trachanas/trahanas (Greek τραχανάς) or (xino)chondros, трахана/тархана (Bulgarian), kishk (Egypt), or kushuk (Iraq) are dried foods based on a fermented mixture of grain and yoghurt or fermented milk, usually consumed as soup. As it is both acid and low-moisture, it preserves milk proteins effectively for long periods. Tarhana is very similar to some kinds of kishk.

The Turkish tarhana consists of cracked wheat (or flour), yoghurt, and vegetables fermented then dried. The Greek cuisine trahana contains only cracked wheat or a cous cous-like pasta and fermented milk. In Cyprus, it is considered a national specialty, and is often flavored with bay leaf, wild thyme, and fennel seed. They are cooked as soup by adding them to stock or water - or to milk (giving them similarity to breakfast cereals).Trahana may be stored as small cakes or as coarse lumps.

History

Hill and Bryer argue that tarhana is akin to τρακτον/tractum, a thickener Apicius wrote about in the first century, which most other authors consider to be a sort of cracker crumb. Dalby (1996) connects it to the described (and condemned) in Galen's Geoponica 3.8. Weaver (2002) also considers it of Western origin.

Perry, on the other hand, argues that the phonetic evolution of τραγανός to tarhana is unlikely, and that it probably comes from Persian tarkhâne. He considers the resemblance to τραγανός and to 'coarse' coincidental, though he speculates that may have influenced the word by folk etymology.

In Persian language sources the name of this food is mentioned in the form of Tarkhana by al-Zamakhshari in his dictionary, in 11th century, and in the form of Tarkhina in Jahangiri encyclopedia (named after Jahangir the Mughal emperor of India), in 13th centruy CE. Tar in Persian means wet or soaked and khan or khwan (both spelled the same and W is not pronounced) means dining place/table, or food, or large wooden bowl. Therefore, in Persian it would mean the watered or soaked food that quite matches the way the soup is made; Tarhana must be soaked in water and other possible ingredients are then added and cooked for some time.

Preparation

Tarhana is prepared by mixing flour, yoghurt or sour milk, and possibly cooked vegetables, salt, and spices (notably tarhana herb); letting the mixture ferment; then drying, grinding, and sieving the result. The fermentation produces lactic acid and other compounds giving tarhana its characteristic taste and keeping properties: the pH is lowered to 3.4-4.2, and the drying step reduces the moisture content to 6-10%, resulting in a medium inhospitable to pathogens and spoilage organisms, while preserving the milk proteins.wadays, tarhana soup is available as a convenience food in the form of dehydrated soup in packets.

25. Write a brief note on Taette Production.

Taette:

The taette is a fermented milk product and it is commonly used in scandivania. This taette is much different from kefir and kumiss. In kefir and kumiss the combination of cultures is used for the fermentation process. That is Streptococcus lactis and Lactobacillus bulgaricus and a lactose fermenting yest is inoculated. But in the taette, the yeast and rope forming strains Streptococcus lactis is inoculated in the milk. The combination of cultures is not added here.

UNIT-III

1.Explain the house committee for quality assurance.

In accordance with clause 2(d)(1) of Rule X of the House of Representatives, theCommittee on Veterans’ Affairs on February 11, 2003, adopted its oversight plan for the108th Congress.This oversight plan is directed at those matters most in need of oversight within thenext two years. The Committee is cognizant of the requirement that it conduct oversighton all significant laws, programs, or agencies within its jurisdiction at least every tenyears. To ensure coordination and cooperation with the other House committees havingjurisdiction over the same or related laws affecting veterans, the Committee will consultas necessary with the Committee on Armed Services, the Committee on Education andthe Workforce, and the Committee on Government Reform.Oversight will be accomplished through committee and subcommittee hearings, fieldand site visits by Members and staff, and meetings and correspondence with interestedparties. Methods of oversight will include existing and requested reports, studies,estimates, investigations and audits by the Congressional Research Service, theCongressional Budget Office, the General Accounting Office, and the Offices of theInspectors General of the Departments of Veterans Affairs and Labor.The Committee will seek the views of veterans’ service organizations, militaryassociations, other interest groups and private citizens. The Committee also welcomescommunications from any individuals and organizations desiring to bring matters to itsattention. A series of joint hearings is scheduled with the Senate Committee onVeterans Affairs at which veterans’ service organizations and military associations willpresent to the committees their national resolutions and agendas for veterans.While this oversight plan describes the foreseeable areas in which the Committee

expects to conduct oversight during the 108th Congress, the Committee and itssubcommittees will undertake additional oversight activities as the need arises.1. VA-administered Insurance Program. The Department of Veterans Affairs (VA)administers six life insurance programs under which two million policies with a value of$20 billion remained in force at the end of fiscal year 2002. The committee will examinepolicy and operational issues VA faces in operating the seventh largest insuranceprogram in the United States.2. Non-Service-Connected Pension Program. The non-service-connected disabilitypension program provides financial assistance to more than 348,000 low-incomeveterans. Veterans must have at least 90 days of military service, including at least oneday of wartime service, and be totally and permanently disabled for employmentpurposes as a result of disability not related to their military service, or over age 65.The committee will examine the administration of this program.3. Improvements in Timeliness of Claims Processing. VA provides over $22 billion a yearin disability compensation and pension benefits to more than 2.4 million veterans. TheVeterans Benefits Administration (VBA) has made many improvements to its operations,including realigning its field offices to improve control of claims and shifting its focusHouse Committee on Veterans' Affairs Page 1 of 6http://veterans.house.gov/about/plan108.html 9/7/2007from resource management to workload management. The committee will focus on theGeneral Accounting Office’s December 2002 report, Veterans Benefits: ClaimsProcessing Timeliness Performance Measure Could be Improved (GAO-03-282).4. State of Veterans’ Employment and Training. From May 1997 to June 2001, theGeneral Accounting Office (GAO) issued eight reports criticizing the Veterans’Employment and Training Service, Department of Labor, for deficiencies in performance,management, and strategic planning. Public Law 107-288, the Jobs for Veterans Act,reformed the nationwide veterans’ employment and training delivery system, focusingon accountability, flexibility, incentives, and results. Further, Public Law 106-50, theVeterans Entrepreneurship and Small Business Development Act of 1999, increasedsmall business opportunities for veterans and disabled veterans by improving theiraccess to capital, information, and markets. The committee will examine implementationof these two laws.5. Troops-To-Teachers. The Troops-To-Teachers program services as an alternativeroute to teacher certification for military servicemembers and retirees who seek asecond career as a public school teacher. The program is funded by the Department ofEducation. The committee plans a joint hearing with the Committee on Education andthe Workforce. The committees expect to examine the skills and experience thatveterans bring to teaching, as well as the administration of the program.6. Role of the Board of Veterans’ Appeals in the 21st Century. The Board of Veterans’Appeals (BVA) is the component of the VA responsible for making the final Departmentaldecision on behalf of the Secretary in appeals of veterans’ benefits claims. Since theadvent of judicial review of appeals of veterans’ claims in 1988, the essential mission ofBVA has remained relatively unchanged. The committee will examine how to mosteffectively use the Board’s expertise and resources in serving veterans.7. Quality Assurance for Disability Claims at the Board of Veterans’ Appeals. Veteranswho are dissatisfied with a decision made by a VA regional office may appeal thatdecision to BVA. During fiscal years 1999 and 2000, BVA decided an average of 35,000appeals per year. GAO reviewed the quality assurance program at the Board and theBoard’s collection of data to improve the quality and consistency of its decisions onveterans’ claims. The committee will focus on the GAO’s August 2002 report, Veterans’Benefits: Quality Assurance for Disability Claims and Appeals Processing Can Be FurtherImproved. (GAO-02-806).8. Vocational Rehabilitation and Employment. VA’s Vocational Rehabilitation andEmployment (VR&E) program provides services and assistance to enable veterans withservice-connected disabilities to obtain and maintain suitable employment, and toenable certain other disabled veterans to achieve independence in daily living. Thecommittee will examine VR&E’s focus on suitable employment, assistance to the mostseriously disabled veterans, succession planning, contracted services, claims processing,employer outreach and quality assurance.9. Office of Federal Contract Compliance Programs. The Office of Federal ContractCompliance Programs (OFCCP) is an enforcement agency within the Department ofLabor. In addition to other equal employment laws, OFCCP enforces the Vietnam Era

Veterans’ Readjustment Assistance Act of 1974 (VEVRAA). The law requires thatemployers with Federal contracts of $100,000 or more provide equal opportunity andaffirmative action for certain veterans. The Federal government awards prime contractsworth approximately $200 billion per year. The committee will examine OFCCP’s recentinvestigatory and enforcement actions related to VEVRAA, staffing matters, and thegeneral complaint process.10. Fiduciary Activities. When a probate court or VA rating board determines an adultVA beneficiary is incompetent, VBA personnel assess the need for a fiduciary, appoint anappropriate person or entity to manage the beneficiary’s funds, and monitor themanagement of those funds. As of December 31, 2002, VBA personnel supervised themanagement of funds for more than 100,000 incompetent beneficiaries. VA’s InspectorGeneral has begun conducting Combined Assessment Program reviews at VBA regionaloffices. The most recent summary report (Report No. 02-01811-38) indicates thatimprovement with regard to Fiduciary and Field Examination activities is needed at morethan 50 percent of the regional offices reviewed between June 2000 and SeptemberHouse Committee on Veterans' Affairs Page 2 of 6http://veterans.house.gov/about/plan108.html 9/7/20072002. The committee will determine the extent of problems with VBA’s fiduciaryprogram and recommendations for improvements.11. Meeting the Health Care Needs of Veterans. Despite record budget increases, thegrowing demand for health care is outpacing the resources allotted to VA for veterans’health care. The committee will evaluate factors that contribute to the loss of currentservices, long waiting times and delayed or denied care. The committee will also reviewthe recommendations of the President’s Task Force to Improve Health Care Delivery forOur Nation’s Veterans and any plans to implement the Task Force’s recommendations.12. Infrastructure Maintenance in VA Health Care and CARES. The VA health caresystem capital asset planning process, known as Capital Assets Realignment forEnhanced Services (CARES) II, is underway, with a scheduled date of completion duringthe 108th Congress. The committee is concerned about the cumulative effects of yearsof insufficient resources to adequately maintain VA’s aging health care facilities. Manyneed significant maintenance, repair and modernization. The committee will reviewthese needs and the implementation of CARES and its next phases.13. Veterans Equitable Resource Allocation System. The Veterans Health Administration(VHA) adopted this system of allocating funds to its field health activities in April 1997.During the past year, the allocation model was revised. The committee will review theimplementation, operation and effectiveness of the new Veterans Equitable ResourceAllocation (VERA) model and its impact on veterans.14. Management Improvements. The VA’s plans in fiscal year 2003 included saving$298 million by making management improvements, with an additional $800 million insavings proposed for fiscal year 2004. The committee will review the business practices,scope and success of VA management improvements.15. VA and DOD Health Resources Sharing. Sections 721 through 726 of Public Law107-314 provided the most significant changes to VA-DOD sharing authority in its 20-year history. With new opportunities and incentives in place to conserve scarce federalhealth care resources and improve the delivery of services to the military-veterancommunity, the committee intends to continue its close oversight of VA-DOD resourcesharing, especially implementation of the new legislation.16. Status of VA Medical, Biological, Chemical and Radiological Research. VA medicalresearch, in affiliation with the nation’s leading schools of medicine, has beenremarkably successful in curing human disease and advancing biomedicine. Thecommittee has monitored VA research for a number of years and will continue to reviewit. Public Law 107-287 expanded the VA’s role in homeland security and created newresearch centers to counter biological, chemical, and radiological terrorism and threatsagainst active duty service members, veterans and the general public. Implementationof the new law will be carefully monitored.17. Mental Health and Substance-Use Disorder Programs. Reported reductions incapacity of VA programs to care for the most seriously mentally ill veterans, especiallythose with psychoses and with substance-use disorders, continue to be a matter ofconcern. The committee will explore the state of VA’s mental health programs and theeffectiveness of chronic mental illness treatment programs in VA’s institutional, contract,community-based, case-management and aftercare programs.18. Follow-up on Millennium Act. Public Law 106-117, the Veterans Millennium Health

Care and Benefits Act, was the most significant health care legislation Congress hasenacted for veterans in a number of years. Since the law was enacted, VA hasimplemented many of its provisions. The committee will continue to give attention tothe remaining steps VA must take to comply fully with its mandates and will provideoversight to those programs already implemented, including the effectiveness of pilotprograms and the maintenance of capacity in VA’s long-term care programs.

2.Explain thePersons involved in internal microbial quality control policy.

Air- and surface-cleaning technologies

The technologies needed to create healthy buildings already exist, but they are not implemented widely enough to interdict

epidemics. Optimized combinations of filtration and ultraviolet germicidal irradiation (UVGI) can be used to remove airborne

microbes with high efficiencies. Combining and optimizing these technologies is the most cost effective means of disinfecting

indoor air.1

Filtration removes airborne particles including mold spores, many bacteria, and allergens.

UVGI eliminates many harmful bacteria and viruses.

Disinfection systems can control bioaerosols.

Existing buildings can be retrofitted with air disinfection systems, but the most economic long-term solution is to construct new

buildings that maintain aerobiological cleanliness by design. Air circulation is often poor in older buildings, and there are limits

to what retrofitted air-cleaning systems can do for them. New buildings can be built in which the airflow is more evenly

distributed and in which effectiveness of air cleaning can be maximized.2 A variety of other technologies, including

photocatalytic oxidation (PCO), ozone, pulsed light, and antimicrobial materials, are also available options for air and surface

biocontamination problems.

Criteria for rating healthy buildings

Modern air disinfection systems can achieve high levels of air cleaning, but limited budgets often require us to ask exactly how

much air cleaning is needed to protect health. This question ultimately hinges on how buildings rate:

aerobiologically — the indoor levels of airborne microbes

epidemiologically — the infection risk of the building

Airborne levels of microbes

We can measure airborne levels of microbes.

Indoor air contains a great variety of bioaerosols, most of which are relatively harmless to healthy humans. The concentration of

airborne microbes in indoor environments, treated collectively without regard to species, provides a reasonable indication of

overall aerobiological air quality. Levels of bacteria and fungi vary by season, with lows in winter, and increase with occupancy,

as people are the primary source of contagious pathogens. Airborne levels are measured in terms of colony-forming units (cfu) of

bacteria or fungi per cubic meter. Some hospital operating rooms are designed to maintain levels as low as 10 cfu/m3, although

this level often proves difficult to achieve. Levels in homes and offices need not be this low, making solutions there less cost-

prohibitive.

Infection risk

We can also estimate infection risk.

The infection risk (IR) of any building might be estimated by collecting data on infection rates and symptoms or through methods

of risk analysis.3 Another approach is to estimate the risk using computer models of building airflow to calculate daily doses of

inhaled contaminants. Airborne levels can be easily, if not always accurately, assessed with air samplers. The IR to an occupant

in a particular building can be evaluated from epidemiological data. The IR can also be inversely viewed as the percentage of

occupants protected from infection, a parameter called the building protection factor (BPF).

The BPF is the complement of the IR— a low IR implies a high BPF— and it can be used to rate and compare buildings under a

common design basis. The BPF is primarily a function of the volume, airflow, outside air fraction, and removal efficiency of the

air disinfection system. Being an intrinsic property of the building, it applies generically to all microbial species.4

Buildings differ according to their operating parameters. A completely unprotected building may have a BPF of 0% to 1%,

whereas a building that maximizes protection of occupants may have a BPF of up to 99%. BPF can be considerably improved in

existing buildings through the addition of air cleaning or other ventilation system improvements.

These measures offer guidelines to buildings.

At least four general categories of buildings have been suggested:1,5

1. Problem buildings foster aerobiological problems or act as amplifiers. Their airborne levels may exceed 10,000 cfu/m3.

IR can approach 99% or more and BPF 1% or less.

2. Normal buildings have average airborne levels, about 500 to 5000 cfu/m3. Typically, IR is about 50% to 75% and BPF

about 25% to 50%.

3. Healthy buildings promote good air quality and health or are above average. Airborne levels are 100 to 1000 cfu/m3.

Typically, IR is less than 50% and BPF 50% or higher.

4. Immune buildings are designed to actively prevent airborne disease transmission. Airborne levels are as low as 10

cfu/m3. IR is less than 10% and BPF 90% or higher.

Disease-free buildings

Buildings concentrate allergens due mainly to the protective effects of shade, warmth, substrate materials, and moisture. For the

same basic reasons, they act as vectors (carriers) for contagious airborne diseases. Humans have been building enclosed habitats

for perhaps half a million years, and in this course of time airborne pathogens evolved the ability to survive indoors just long

enough to transmit to new hosts. They have adapted to our enclosed habitats so completely that they cannot survive outdoors.

This evolutionary process accelerated when man began husbanding animals, from which almost all human pathogens seem to

have jumped species. The evolutionary process continues today as emerging pathogens adapt to indoor transmission, and the

number of new disease species has increased exponentially over time, in concert with the size and density of the human

population.4

Can we immunize buildings?

By designing our habitats strictly for human comfort, we have unwittingly fostered the adaptation and proliferation of dangerous

pathogens. It is only by re-engineering our buildings to eliminate, rather than foster, airborne disease transmission that we can

reverse this evolutionary trend. By immunizing enough buildings against disease, it is theoretically possible to develop herd

immunity in a community or city. The percentage of buildings that would need to be immunized to block an airborne epidemic is

similar to the percentage of a population vaccinated to achieve herd immunity, and depending on the contagiousness of the

species, this may be as low as 30%.4

In addition to air disinfection and improved delivery of clean air, there are other factors that can aid in the development of

healthy buildings. Rugs, carpets, furniture, draperies, and the like can absorb mold spores and regenerate new ones if they

become wet. Material selectivity can be one beneficial approach, and other alternatives include the use of self-disinfecting

materials, pressurization, and isolation of zones within buildings, including the provision of buffer zones between the inside and

outdoor air and the creation of clean inner zones safe from airborne health threats.

3.Explain the Quality check at every step from collection of raw materials till it reaches the customer.The trade of spices has been an integral part of our business, since our inception. We began our business in Kerala as suppliers of spices from Kerala to West Bengal. Our expertise in the spices trade, ages back to the 1970’s. It is one of the primary business ventures of the group.Since then, the company has been setting foot into diversified business.

Navin Trading Company is a subsidiary of Jaihind Traders, which has a tradition of over 30 years into various business fields like Spices, Iron and Steel, Aluminium, Composite Panels, Commodity Trading, etc. We started our operations in Cochin, with our office at Mattanchery, which has been the hub of spices trade in Kerala. Navin Trading Company has won the Export Award for 1999 – 2000. We are pioneers in the trade of black pepper.

Today, an ISO 22000: 2005, HACCP , FSMS certified company, Navin Trading is one of the key players in the spices export from Kerala. With over thirty years into the spices trade, are pioneers in the trade of black pepper. All our processing operations are strictly in conformity with the International Quality norms laid by HACCP Hazard Analysis at Critical Control Points. Our modern processing facilities for the products include a full line of drying, cleaning, grinding, sizing, sieving, blending and storage facility, in order to cater to all the specific requirements of our customers. The cleaning process includes, pre-cleaning, classifying, drying, de-stoning, magnetic separation, spirals sortex, etc. Products are controlled by in-house state of the art approved laboratory by qualified staff. Our quality assurance programme emphasizes product safety through FSMS Food Safety Management System.Zest for knowledge and the ability to go the extra mile has always been our plus points, giving us the cutting edge in this highly global and dynamic business environment.

Quality Policy / Processes

Quality Policy:

Quality control is a process that is respected in the company and every employee is made to understand that no product we manufacture can be less than the best. Authorities and quality control agencies are convinced about our quest for quality and employee satisfaction.

Navin Trading is an ISO 22000: 2005, HACCP , FSMS certified company into the spices industry. All our processing operations are strictly in conformity with the International Quality norms laid by HACCP (Hazard Analysis at Critical Control Points). This ensures a perfect machinery of checks at every step right from the raw material procurement stage till the product reaches the warehouse of the consumer. we reach for new horizons only to initiate the journey towards the next.

We have a state of the art factory at Aluva, with a fully functional Quality control laboratory. All incoming raw materials are thouroughly inspected before it enters the processing line. The products are then passed through numerous quality control processes, strictly moniterd at each stage. The end product is finally released only after the approval of a team of trained quality control personel, inorder to ensure that we deliver the finest products.

Infrastructure

Navin Trading is an ISO 22000: 2005, HACCP , FSMS certified company into the spices industry. All our processing operations are strictly in conformity with the International Quality norms laid by HACCP (Hazard Analysis at Critical Control Points). This ensures a perfect machinery of checks at every step right from the raw material procurement stage till the product reaches the warehouse of the consumer. we reach for new horizons only to initiate the journey towards the next.Our modern processing facilities for the products include a full line of drying, cleaning, grinding, sizing, sieving, blending and storage facility, in order to cater to all the specific requirements of our customers. The cleaning process includes, pre-cleaning, classifying, drying, de-stoning, magnetic seperation, spirals (sortex), etc. Products are controlled by in-house state of the art approved laboratory by qualified staff. Our quality assurance programme emphasizes product safety through FSMS.We have a state of the art factory at Aluva, with a fully functional Quality control laboratory. All incoming raw materials are thouroughly inspected before it enters the processing line. The products are then passed through numerous quality control processes, strictly moniterd at each stage. The end product is finally released only after the approval of a team of trained quality control personel, inorder to ensure that we deliver the finest products.

Raw Materials

Milk containers are made from paperboard coated with a waterproof plastic, generally polyethylene. The wood pulp that is used

to make paperboard for milk cartons is a blend of softwood and hardwood. Softwood is usually a type of pine, though the actual

trees used vary depending on the location of the paper mill. Softwood produces long wood fibers that provide strength to the

paperboard. Hardwood comes from deciduous trees such as oaks. Hardwood has shorter fibers that make for a better printing

surface. Pulp for milk carton board is usually 60% hardwood and 40% soft.

Several other chemicals are used to make milk cartons. One is oxygenated chlorine, which bleaches the wood pulp. Other

chemicals specific to each manufacturer are added to the paper to add strength. Chemical pigments in the ink are used for the

printing process as well.

The Manufacturing

Process

Making the paperboard

1 The heavy paper used for milk cartons is categorized as a type of paperboard. It is typically made on a Fourdrinier

machine, one of the oldest and most common types of papermaking equipment. The process begins with wood chips.

The chips are heated and bathed in chemicals that soften them and break them into small bits of wood fiber. The pulp is

bleached in a bath of oxygenated chlorine. The pulp is then washed and passed through several screens, to remove

debris. Next, the pulp is fed through a machine called a refiner, which grinds the wood fibers between rotating disks.

The refined pulp flows into the headbox of the Fourdrinier machine. In the headbox, a mixture of water and pulp is

spread across a continually moving screen. The water drains away below through the openings in the screen, leaving a

mat of damp wood fiber. The mat is drawn through huge rollers that squeeze out additional water. Next, the paperboard

is dried, by passing it over steam-heated cylinders.

Applying waterproof coating

2 The dried paperboard next moves through the rollers of an extruder. As the paperboard is pulled through the rollers,

the machine extrudes a small amount of molten polyethylene. The polyethylene clings to both sides of the paperboard

in a thin film. Several grades of polyethylene may be combined in the extruder, and the machine actually lays down

multiple layers of film in one pass. The different layers accomplish different tasks, such as reducing moisture

penetration, reducing oxygen penetration, and aiding in essential oil retention. As the paperboard comes through the

extruder, it passes over a chilled roller, which cools both surfaces. The paper now has an extremely glossy, waterproof

finish. It is wound into a large roll, to be transported to the printing area. The roll is typically 120 in (3.05 m) wide, too

big to fit onto the printing and cutting machine. The large roll is slit into narrower rolls, the width determined by the

desired dimensions of the finished carton.

Printing and cutting the blank

3 Printing is usually done by the flexo-graphic method, which uses rubber printing plates attached to steel shells.

Workers load the roll of polyethylene-coated paperboard into the press. The press prints the words and images of the

milk carton onto the paperboard. A typical milk carton might be printed in anything from one to seven colors. All of the

colors are printed at one pass through the machine. Next, the same machine scores the paperboard along what will be

the edges of the carton, where the box will fold later. A die lowers, and stamps out the carton. If you cut open an empty

milk carton down one side and across the bottom and unfold it, you can see the shape of the cut piece. This flat, scored,

and printed piece is called a blank. The high-speed printing and cutting equipment turns out hundreds of blanks per

minute.

Sealing the blanks

4 Workers at the carton plant next load the blanks into a sealing machine. The machine takes the flat blank and folds it

laterally, creating an overlapping side seam. The seam is then heated and squeezed together. The heated polyethylene

bonds and the seam are strong and watertight without any additional glue. Thousands of blanks per minute shoot

through the sealing machine. This is the final step at the carton manufacturer. The rest of the process is completed at

the dairy. The sealed and folded blanks are loaded into corrugated cartons, and they are shipped.

4.Explain theImplementation of ISO Standards and history.

ISO 22000 is a standard developed by the International Organization for Standardization dealing with food safety. This is a general derivative of ISO 9000.

.. Food safety

Food safety is linked to the presence of food-borne hazards in food at the point of consumption. Since food safety hazards can occur at any stage in the food chain it is essential that adequate control be in place. Therefore, a combined effort of all parties through the food chain is required.

ISO 22000 standard

The ISO 22000 international standard specifies the requirements for a food safety management system that involves the following elements:

interactive communication

system management

prerequisite programs

HACCP principles

Critical reviews of the above elements have been conducted by many scientists [1], [2], [3], [4]. Communication along the food chain is essential to ensure that all relevant food safety hazards are identified and adequately controlled at each step within the food chain. This implies communication between organizations both upstream and downstream in the food chain. Communication with customers and supplies about identified hazards and control measures will assist in clarifying customer and supplier requirements.

Recognition of the organization's role and position within the food chain is essential to ensure effective interactive communication throughout the chain in order to deliver safe food products to the final consumer.

The most effective food safety systems are established, operated and updated within the framework of a structured management system and incorporated into the overall management activities of the organization. This provides maximum benefit for the organization and interested parties. ISO 22000 has been aligned with ISO 9001 in order to enhance the compatibility of the two standards.

ISO 22000 can be applied independently of other management system standards or integrated with existing management system requirements.

ISO 22000 integrates the principles of the Hazard Analysis and Critical Control Point (HACCP) system and application steps developed by the Codex Alimentarius Commission. By means of auditable requirements, it combines the HACCP plan with prerequisite programmes. Hazard analysis is the key to an effective food safety management system, since conducting a hazard analysis assists in organizing the knowledge required to establish an effective combination of control measures. ISO 22000 requires that all hazards that may be reasonably expected to occur in the food chain, including hazards that may be associated with the type of process and facilities used, are identified and assessed. Thus it provides the means to determine and document why certain identified hazards need to be controlled by a particular organization and why others need not.

During hazard analysis, the organization determines the strategy to be used to ensure hazard control by combining the prerequisite programmes and the HACCP plan.

ISO is developing additional standards that are related to ISO 22000. These standards will be known as the ISO 22000 family of standards. At the present time, the following standards will make up the ISO 22000 family of standards:

ISO 22000 - Food safety management systems - Requirements for any organization in the food chain.

ISO 22001 - Guidelines on the application of ISO 9001:2000 for the food and drink industry (replaces: ISO 15161:2001).

ISO/TS 22002- Prerequisite programmes on food safety -- Part 1: Food manufacturing

ISO TS 22003 - Food safety management systems for bodies providing audit and certification of food safety management systems.

ISO TS 22004 - Food safety management systems - Guidance on the application of ISO 22000:2005.

ISO 22005 - Traceability in the feed and food chain - General principles and basic requirements for system design and implementation.

ISO 22006 - Quality management systems - Guidance on the application of ISO 9002:2000 for crop production.

ISO 22000 is also used in the Food Safety Systems Certification (FSSC) Scheme FS22000. FS22000 is a Global Food Safety Initiative (GFSI) approved scheme.

ISO 9001 vs ISO 22000

In comparison with ISO 9001, the standard is a more procedural orientated guidance than a principle based one. Apart from that, ISO 22000 is an industrial-specific risk management system for any type of food processing and marketing, which can be closely

incorporated with the quality management system of ISO 9001. The detailed similarities and differences of the two standards can be found elsewhere

Potential justification

In 2004, European Office of Crafts, Trades and Small and Medium-sized Enterprises for Standardisation addressed that the standard is only suitable for large sized companies and small food businesses will not be able to seek such a high standard due to the lack of resources to pursue the certification. The agency suggests to create an alternative for small food business to achieve the same objective [9]. EFSA is now making their efforts on the food legislations that are adaptable for the SMEs in food supply chains [10]. A few critics also proposed that organizations which seek the standard certification should also do the same to the ISO 14001 along with the ISO 9001, as they consider that large amounts of risks are mainly from the primary production in the supply chains rather than the later stages of food processing .

ISO14000 - Introduction

After the success of the ISO9000 series of quality standards, the International Standards Organization published a comprehensive set of standards for environmental management. This series of standards is designed to cover the whole area of environmental issues for organizations in the global marketplace.

History of DevelopmentThe ISO 14000 series emerged primarily as a result of the Uruguay round of the GATT negotiations and the Rio Summit on the Environment held in 1992. While GATT concentrates on the need to reduce non-tariff barriers to trade, the Rio Summit generated a commitment to protection of the environment across the world. The environmental field has seen a steady growth of national and regional standards. The British Standards Institution has BS 7750, the Canadian Standards Association has environmental management, auditing, eco-labeling and other standards, the European Union has all of these plus the eco-management and audit regulations, and many other countries (e.g. USA, Germany and Japan) have introduced eco-labeling programs.

After the rapid acceptance of ISO 9000, and the increase of environmental standards around the world, ISO assessed the need for international environmental management standards. They formed the Strategic Advisory Group on the Environment (SAGE) in 1991, to consider whether such standards could serve to:

Promote a common approach to environmental management similar to quality management;

Enhance organizations' ability to attain and measure improvements in environmental performance; and

Facilitate trade and remove trade barriers.

In 1992, SAGE's recommendations created a new committee, TC 207, for international environmental management standards. The committee, and its sub-committees include representatives from industry, standards organizations, government and environmental organizations from many countries. The new series of ISO14000 standards are designed to cover:

environmental management systems

environmental auditing

environmental performance evaluation

environmental labeling

life-cycle assessment

environmental aspects in product standards

Why have these standards ?

A set of international standards brings a world-wide focus to the environment, encouraging a cleaner, safer, healthier world for us all. The existence of the standards allows organizations to focus environmental efforts against an internationally accepted criteria.

At present many countries and regional groupings are generating their own requirements for environmentla issues, and these vary between the groups. A single standard will ensure that there are no conflicts between regional interpretations of good environmental pactice.

The fact that companies may need environmental management certification to compete in the global marketplace could easily overshadow all ethical reasons for environmental management. Within Europe, many organizations gained ISO9000 Registration primarily to meet growing demands from customers. ISO 9000 quality registration has become necessary to do business in many areas of commerce. Similarly, the ISO 14000 management system registration may become the primary requirement for doing business in many regions or industries.

Who do the standards apply to ?

The standards apply to all types and sizes of organizations and are designed to encompass diverse geographical, cultural and social conditions. For ISO14001, except for committing to continual improvement and compliance with applicable legislation and regulations, the standard does not establish absolute requirements for environmental performance. Many organizations, engaged in similar activities, may have widely different environmental management systems and performance, and may all comply with ISO14001.

What do the standards apply to ?

This is primarily for the company to decide, and to clearly document the extent of coverage. However, limiting coverage to a small [inconsequential] area may provide competitors with an ideal marketing opportunity!. There does not appear to be a limit to the coverage of the environmental management system in that it can include the organization's products, services, activities, operations, facilities, transportation, etc.From a slightly different viewpoint, all of the elements in the previous sentence should be considered for environmental impact resulting from current practices, past practices and future practices, ......and should further be reviewed for their impact under normal, abnormal and emergency conditions.

What does the ISO 14000 Series cover ?The best way to answer this question is to provide a list of the proposed standards:

Standard Title / Description

14000Guide to Environmental Management Principles, Systems and Supporting Techniques

14001 Environmental Management Systems - Specification with Guidance for Use

14010 Guidelines for Environmental Auditing - General Principles of Environmental Auditing

14011Guidelines for Environmental Auditing - Audit Procedures-Part 1: Auditing of Environmental Management Systems

14012Guidelines for Environmental Auditing - Qualification Criteria for Environmental Auditors

14013/15Guidelines for Environmental Auditing - Audit Programmes, Reviews & Assessments

14020/23 Environmental Labeling

14024Environmental Labeling - Practitioner Programs - Guiding Principles, Practices and Certification Procedures of Multiple Criteria Programs

14031/32 Guidelines on Environmental Performance Evaluation

14040/43 Life Cycle Assessment General Principles and Practices

14050 Glossary

14060 Guide for the Inclusion of Environmental Aspects in Product Standards

General Description of ISO14001

ISO14001 requires an Environmental Policy to be in existence within the organisation, fully supported by senior management, and outlining the policies of the company, not only to the staff but to the public. The policy needs to clarify compliance with Environmental Legislation that may effect the organization and stress a commitment to continuous improvement. Emphasis has been placed on policy as this provides the direction for the remainder of the Management System.

Those companies who have witnessed ISO9000 Assessments will know that the policy is frequently discussed during the assessment, many staff are asked if they understand or are aware of the policy, and any problems associated with the policy are seldom serious. The Environmental Policy is different, this provides the initial foundation and direction for the Management System and will be more stringently reviewed than a similar ISO9000 policy. The statement must be publicised in non-technical language so that it can be understood by the majority of readers. It should relate to the sites within the organisation encompassed

by the Management System, it should provide an overview of the company’s activities on the site and a description of those activities. A clear picture of the company’s operations.

The preparatory review and definition of the organization's environmental effects is not part of a ISO14001 Assessment, however examination of this data will provide an external audit with a wealth of information on the methods adopted by the company. The preparatory review itself should be comprehensive in consideration of input processes and output at the site. This review should be designed to identify all relevant environmental aspects that may arise from existence on the site. These may relate to current operations, they may relate to future, perhaps even unplanned future activities, and they will certainly relate to the activities performed on site in the past (i.e. contamination of land).

The initial or preparatory review will also include a wide-ranging consideration of the legislation which may effect the site, whether it is currently being complied with, and perhaps even whether copies of the legislation are available. Many of the environmental assessments undertaken already have highlighted that companies are often unaware of ALL of the legislation that affects them, and being unaware, are often not meeting the requirements of that legislation.

The company will declare its primary environmental objectives, those that can have most environmental impact. In order to gain most benefit these will become the primary areas of consideration within the improvement process, and the company’s environmental program. The program will be the plan to achieve specific goals or targets along the route to a specific goal and describe the means to reach those objectives such that they are real and achievable. The Environmental Management System provides further detail on the environmental program. The EMS establishes procedures, work instructions and controls to ensure that implementation of the policy and achievement of the targets can become a reality. Communication is a vital factor, enabling people in the organisation to be aware of their responsibilities, aware of the objectives of the scheme, and able to contribute to its success.

As with ISO9000 the Environmental Management System requires a planned comprehensive periodic audit of the Environmental Management System to ensure that it is effective in operation, is meeting specified goals, and the system continues to perform in accordance with relevant regulations and standards. The audits are designed to provide additional information in order to exercise effective management of the system, providing information on practices which differ to the current procedures or offer an opportunity for improvement.

In addition to audit, there is a requirement for Management Review of the system to ensure that it is suitable (for the organization and the objectives) and effective in operation. The management review is the ideal forum to make decisions on howe to improve for the future.

5.Explain thePrinciples and use of HACCP in Food industry.

Basic principles of HACCP

There are seven discrete activities that are necessary to establish, implement and maintain a HACCP plan, and these are referred to as the 'seven principles' in the Codex Guideline (1997).

The seven principles are[1]:

Principle 1Conduct a hazard analysis.

Identify hazards and assess the risks associated with them at each step in the commodity system. Describe possible control measures.

Principle 2Determine the Critical Control Points (CCPs)

A critical control point is a step at which control can be applied and is essential to prevent or eliminate a food safety hazard, or reduce it to an acceptable level. The determination of a CCP can be facilitated by the application of a decision tree, such as the one given in Appendix IV.

Principle 3Establish critical limits.

Each control measure associated with a CCP must have an associated critical limit which separates the acceptable from the unacceptable control parameter.

Principle 4Establish a monitoring system

Monitoring is the scheduled measurement or observation at a CCP to assess whether the step is under control, i.e. within the critical limit(s) specified in Principle 3.

Principle 5Establish a procedure for corrective action, when monitoring at a CCP indicates a deviation from an established critical limit.

Principle 6Establish procedures for verification to confirm the effectiveness of the HACCP plan.

Such procedures include auditing of the HACCP plan to review deviations and product dispositions, and random sampling and checking to validate the whole plan.

Principle 7Establish documentation concerning all procedures and records appropriate to these principles and their application

Application of HACCP to mycotoxin control

Once tasks 1 to 5 have been completed the following will be in place: a HACCP team, a Description and Intended Use table, and a verified Commodity Flow Diagram. This will provide information on a specific commodity from a unique source, and this information is required to complete the hazard analysis. See the case studies in Chapter 3 for examples of implementation, including that of stages 1 to 5.

Task 6 - Mycotoxin hazard analysis and identification of possible control measures

Hazard Analysis

a) Identification of mycotoxin hazard

For a given commodity system in a particular location, the HACCP team need to first consider which, if any, of the mycotoxins known to constitute a food safety hazard are likely to be present.

Over 300 mycotoxins are known, but only a relatively few of these are widely accepted as presenting a significant food or animal feed safety risk. These hazardous mycotoxins are listed in Tables 1 and 2 in Chapter 1. Of these only the following mycotoxins have regulatory limits set by one or more countries: the aflatoxins (including aflatoxin M1), ochratoxin A, zearalenone, patulin, ergot alkaloids, and deoxynivalenol. Guideline limits exist for fumonisin B1 and regulatory limits are likely to be set in the near future. The regulatory limits are taken as the target levels and should be included in the Product Description table. Mycotoxin limits can also be set by the customer in specific contracts and it is possible that these may include mycotoxins not subject to regulatory limits.

The risk of a particular mycotoxin hazard should be estimated using well established data on the relative susceptibilities of commodities to given mycotoxins and the climatic conditions required for the mycotoxins to be produced. The EU has identified

the following animal feed ingredients, and their products, as being highly susceptible to aflatoxin contamination: maize, groundnut cake, cottonseed cake, babassu, palm kernel cake and copra cake. The EU has also identified the following foodstuffs as highly susceptible to aflatoxin contamination: dried figs and other dried fruit, groundnuts, pistachios and other edible nuts and cereals. These commodities are specified in the respective EC regulations (1525/98 amending regulation 194/97). Maize grown in temperate climates would be less likely to be contaminated with aflatoxin, but could be contaminated with trichothecene mycotoxins or fumonisin B1. Although published mycotoxin survey data exists for many commodities, it is important that surveillance studies are performed if mycotoxin data is lacking for a particular commodity, or for production in a particular climatic zone.

b) Identification of steps in the Commodity Flow Diagram (CFD) where mycotoxin contamination is most likely to occur

Once the mycotoxin hazard(s) has been identified, each step in the CFD must be considered in turn and the likelihood of mycotoxin contamination occurring must be assessed. Usually published scientific data will be available to act as a guide, but it may be necessary to commission a study to determine, or confirm that the correct steps have been identified. The situation may change from year to year, and season to season, so there will need to be an element of mycotoxin surveillance in the HACCP plan.

An important fact to establish is whether pre-harvest contamination with mycotoxins is likely or whether contamination occurs primarily post-harvest. Mycotoxins produced by Fusarium spp, such as fumonisin B1 are invariably produced pre-harvest, but climatic conditions effect the degree of blight and the resultant level of mycotoxin contamination. Aflatoxins can be produced both pre-harvest and post-harvest and climatic conditions can have a significant bearing: drought stress favours pre-harvest contamination, whereas post-harvest handling during the rainy season favours post-harvest aflatoxin contamination.

It is rarely possible to be certain that pre-harvest mycotoxin levels are below regulatory or target levels in the commodity system, so post-harvest mycotoxin control measures can often only prevent or reduce ADDITIONAL contamination, rather than prevent the hazard completely. Consequently it is often necessary to introduce a segregation step to remove any batches containing an unacceptable level of mycotoxin.

c) Possible Mycotoxin Control Measures

The most effective mycotoxin control measures is to dry the commodity such that the water activity (aw) is too low to support mould growth and/or prevent mycotoxin production. To prevent the growth of most moulds the aw needs to be £ 0.70, which translates to a moisture content of approximately 14% for maize and 7.0% for groundnuts at 20°C (the corresponding moisture content decreases as the temperature increases). Each toxigenic mould has its own minimum water activity for growth and mycotoxin production and these translate into moisture contents for each commodity. These moisture contents are termed 'safe' and would be the critical limit for the control measure.

It is important to specify a target 'safe' moisture content with a maximum as well as an average value, e.g. 14% no part exceeding 15%. If only an average value is specified it may conceal a large range of moisture contents within the batch and the commodity would not be safe from mould growth and mycotoxin contamination. A drying process is required which dries evenly and the critical limits must be set bearing this in mind. Validation of such a CCP must involve moisture determination of multiple samples.

If the commodity is at an 'unsafe' moisture content for longer than 48 hours, then mould can grow and mycotoxins be produced. Hence limiting the time that the commodity spends in the 'unsafe' moisture content window to less than 48 hours is a control measure. This explains why timely sun-drying can sometimes be safer than delayed mechanical drying. Two days on a drying floor with occasional turning can often achieve the target 'safe' moisture content, whereas a back-log at the mechanical drier can result in the critical limit of 48 hours not being met.

Once produced, it is not usually possible to remove mycotoxins, other than by physical separation (grading) techniques. To apply this type of control measure, representative samples of batches of commodity are collected and tested for selected mycotoxins. Only those batches containing less than the critical limit of mycotoxin, as specified in official regulations, are accepted. For some commodities, such as blanched groundnuts, colour sorters may be effective in rejecting individual high-aflatoxin nuts and accumulating low-aflatoxin nuts, and may be classified as a control measure.

There are a few examples where effective chemical detoxification is possible, such as ammoniation of certain animal feed ingredients and refining of vegetable oils. These are control measures that would also be suitable for application at a critical control point for aflatoxin, but only for the specified commodities.

It is essential that GAP, GSP, and GMP pre-requisites are in place, and simply ensuring that this is the case can significantly reduce the risk of the mycotoxin hazard. Examples of procedures which fall within the scope of these pre-requisites include: irrigation, insect control, use of resistant varieties, and use of pallets in store.

Task 7 - Determine Critical Control Points (CCPs)

Determination of CCPs can be achieved using a well designed decision tree, if necessary, to supplement the knowledge and experience of the HACCP team (see Appendix IV). Each step in the CFD is considered in turn, and the questions answered in sequence. It should be noted that it is necessary to be able to answer Yes to Question 1 (Do preventative control measures exist?) before a CCP can be established. The Codex 1997 definition of a control measure is any action and activity that can be used to prevent or eliminate a food safety hazard, or reduce it to an acceptable level.

There are commodity systems, such as the production of apple juice (Case study 5), where control measures are possible at a number of steps, and each is capable of achieving a known percentage reduction in the level of mycotoxin. It is possible, therefore, to calculate the acceptable level of patulin at each step and perform validation. If the risk of the acceptable level of mycotoxin being exceeded is considered to be sufficiently low, then the HACCP team may determine each of the steps as CCPs.

Task 8 - Establish critical limits for each CCP

When the control measure is segregation based on mycotoxin analysis, then the critical limit will often be set at the acceptable level, which in turn will be set at, or below, the regulatory mycotoxin limit. Acceptable levels, and any associated critical limits, can sometimes be set higher than a regulatory limit, provided that a subsequent step can guarantee to attain the acceptable level of hazard in the final product.

For control measures that involve drying to a 'safe' moisture content, the parameter that will be measured, and for which critical limits will be set, will usually be parameters such as the temperature of the drier and the dwell time, e.g. for a continuous flow drier the critical limit for temperature could be 80 +/- 2°C and the critical limit for dwell time could be 20 +/- 1 minute.

Critical limits for chemical detoxification could be the temperature and pressure of the reaction vessel and the dwell time.

Task 9 - Establish a monitoring system for each CCP

The monitoring system must be a scheduled measurement, usually of a basic parameter such as temperature or time, to detect any deviation from the critical limits.

When segregation of acceptable and unacceptable batches is required in the agricultural system, for example at a secondary trader, then rapid testing procedures are needed to test incoming batches.

A number of semi-quantitative immunoaffinity rapid test kits are available which work to a stated target level, eg 5 or 20 µk/kg of the appropriate mycotoxin. Here the critical limit would normally be the presence or absence of a coloured derivative. More traditional mini-column and TLC dilution to extinction techniques can still be useful for segregation of batches at the factory gate, and for these the presence or absence of a blue fluorescent band or spot is the critical limit.

Task 10 - Establish a corrective action

There are two sorts of corrective action. The first is action to regain control. For instance if a critical limit for a moisture content is not attained, then the corrective action could be to check the specification of the drier and effect repairs, or perhaps to increase the temperature setting or the dwell time. The second type of corrective action is to isolate the product produced whilst the CCP was out of control and amend the product disposition, by either discarding or down-grading it, or re-processing it if this is appropriate.

Task 11 - Establish verification procedures

At regular, specified, intervals the complete HACCP plan should be verified by checking that the levels of mycotoxin in the final product are within acceptable levels. If this is found not to be the case, then immediately trouble-shooting should be carried out to identify the step at which the hazard has become out of control. Critical limits may need to be amended, or a new control measure

may need to be validated and introduced. Similarly, if a review of deviations and product dispositions indicated an unacceptable degree of control at a particular CCP, then revisions will need to be made.

Task 12 - Establish documentation and record keeping

Standard HACCP documentation and record keeping is appropriate, but the complexity of the records should reflect the sophistication of the step in the commodity system.

UNIT-IV

MICROBIOLOGICAL EXAMINATION OF FOOD:-

Introduction

The stated chief purposes of microbiological criteria for foods are to give assurance:

1. That the foods will be acceptable from the Public health standpoint that is will not be responsible for the spread of infectious disease or for food poisoning.

2. That the foods will be of satisfactory quality3. The foods will have keeping qualities that should be expected of the product.4. Sampling for tests is a problem since the lack of homogeneity in most foods makes location, size and number

of samples significant.5. Standards usually are based on total numbers of organisms, numbers of organisms, numbers of indicator

organisms or numbers of pathogens.

1.Explain the Indicator organisms in detail.

It may be necessary to carry out a microbiological examination of a food for one or more of a number of reasons. Escherichia coli is a natural component of the human gut flora and its presence in the environment, or on foods, generally

implies some history of contamination of faecal origin. Traditional the group chosen has been designated the coliforms- those organisms capable of fermenting lactose in the

presence of bile at 37C. This will include most strains of E. coli but also includes organisms such as Citrobactor and Enterobactor.

Indicator organism

Indicator organisms are used to measure potential fecal contamination of environmental samples. The presence of coliform

bacteria, such as E. coli, in surface water is a common indicator of fecal contamination. Coliform bacteria in water samples may

be quantified using the most probable number (MPN) method, a probabilistic test which assumes cultivable bacteria meet certain

growth and biochemical criteria. If preliminary tests suggest that coliform bacteria are present at numbers in excess of an

established cut-off (the Coliform Index), fecal contamination is suspected and confirmatory assays such as the Eijckman test are

conducted.[citation needed]

Coliform bacteria selected as indicators of fecal contamination must not persist in the environment for long periods of time

following efflux from the intestine, and their presence must be closely correlated with contamination by other fecal organisms.

Indicator organisms need not be pathogenic.[1]

Direct-to-Consumer genetic testing

Direct-to-Consumer (DTC) genetic testing is a type of genetic test that is accessible directly to the consumer without having to go

through a health care professional. Usually, to obtain a genetic test, health care professionals such as doctors acquire the

permission of the patient and order the desired test. DTC genetic tests, however, allow consumers to bypass this process and

order one themselves. There are a variety of DTC tests, ranging from testing for breast cancer alleles to mutations linked to cystic

fibrosis. Benefits of DTC testing are the accessibility of tests to consumers, promotion of proactive healthcare and the privacy of

genetic information. Possible additional risks of DTC testing are the lack of governmental regulation and the potential

misinterpretation of genetic information.

2.Explain the Immunological methods in detail.

Immunological methods

Indirect immunofluorescence

ELISA

Immunoblotting (Western blot)

Complement fixation test

Immunofluorescence

Microphotograph of a histological section of human skin prepared fordirect immunofluorescence using an anti-IgA antibody.

The skin is from a patient with Henoch-Schonlein purpura: IgA deposits are found in the walls of small superficial capillaries

(yellow arrows). The pale wavy green area on top is the epidermis, the bottom fibrous area is the dermis.

Microphotograph of a histological section of human skin prepared fordirect immunofluorescence using an anti-IgG antibody.

The skin is from a patient with systemic lupus erythematosus and shows IgG deposit at two different places: The first is a band-

like deposit along the epidermalbasement membrane ("lupus band test" is positive). The second is within the nuclei of

the epidermal cells (anti-nuclear antibodies).

Immunofluorescence is a technique used for light microscopy with a fluorescence microscope and is used primarily

on biological samples. This technique uses the specificity of antibodies to theirantigen to target fluorescent dyes to

specific biomolecule targets within a cell, and therefore allows visualisation of the distribution of the target molecule through the

sample. Immunofluorescence is a widely used example of immunostaining and is a specific example

of immunohistochemistry that makes use of fluorophores to visualise the location of the antibodies. [1]

Immunofluorescence can be used on tissue sections, cultured cell lines, or individual cells, and may be used to analyse the

distribution of proteins, glycans, and small biological and non-biological molecules. Immunofluoresence can be used in

combination with other, non-antibody methods of fluorescent staining, for example, use of DAPI to label DNA. Several

microscope designs can be used for analysis of immunofluorescence samples; the simplest is the epifluorescence microscope, and

theconfocal microscope is also widely used. Various super-resolution microscope designs that are capable of much higher

resolution can also be used.[2]

Types of immunofluorescence

There are two classes of immunofluorescence techniques, primary (or direct) and secondary (or indirect).

Primary (direct)

Primary, or direct, immunofluorescence uses a single antibody that is chemically linked to afluorophore. The antibody recognises

the target molecule and binds to it, and the fluorophore it carries can be detected via microscope. This technique has several

advantages over the secondary (or indirect) protocol below because of the direct conjugation of the antibody to the fluorophore.

This reduces the number of steps in the staining procedure, is therefore faster, and can avoid some issues with antibody cross-

reactivity or non-specificity, which can lead to increased background signal.

Secondary (indirect)

Secondary, or indirect, immunofluorescence uses two antibodies; the first (the primary antibody) recognises the target molecule

and binds to it, and the second (the secondary antibody), which carries the fluorophore, recognises the primary antibody and

binds to it. This protocol is more complex than the primary (or direct) protocol above and takes more time but allows more

flexibility.

This protocol is possible because an antibody consists of two parts, a variable region (which recognizes the antigen) and an

invariant region (which makes up the structure of the antibody molecule). A researcher can generate several primary antibodies

that recognize various antigens (have different variable regions), but all share the same invariant region. All these antibodies may

therefore be recognized by a single secondary antibody. This saves the cost of modifying the primary antibodies to directly carry

a fluorophore.

Different primary antibodies with different invariant regions are typically generated by raising the antibody in different species.

For example, a researcher might create primary antibodies in a goat that recognize several antigens, and then employ dye-coupled

rabbit secondary antibodies that recognize the goat antibody invariant region ("rabbit anti-goat" antibodies). The researcher may

then create a second set of primary antibodies in a mouse that could be recognised by a separate "donkey anti-mouse" secondary

antibody. This allows re-use of the difficult-to-make dye-coupled antibodies in multiple experiments.

Limitations

As with most fluorescence techniques, a significant problem with immunofluorescence is photobleaching. Loss of activity caused

by photobleaching can be controlled by reducing the intensity or time-span of light exposure, by increasing the concentration of

fluorophores, or by employing more robust fluorophores that are less prone to bleaching (e.g., Alexa Fluors, Seta Fluors,

or DyLight Fluors).

In general, immunofluorescence is limited to fixed (i.e., dead) samples. Analysis of structures within live cells by

immunofluorescence is not possible, as antibodies cannot cross the cell membrane. As such some uses of immunofluorescence

have been outmoded by the development of recombinant proteins containing fluorescent protein domains, e.g., green fluorescent

protein (GFP). Use of such "tagged" proteins allows determination of their localisation in live cells.

ELISA

Enzyme-linked immunosorbent assay (ELISA), also known as an enzyme immunoassay(EIA), is a biochemical technique

used mainly in immunology to detect the presence of anantibody or an antigen in a sample. The ELISA has been used as

a diagnostic tool in medicine and plant pathology, as well as a quality control check in various industries. In simple terms, in

ELISA, an unknown amount of antigen is affixed to a surface, and then a specific antibody is applied over the surface so that it

can bind to the antigen. This antibody is linked to an enzyme, and in the final step a substance is added that the enzyme can

convert to some detectable signal, most commonly a colour change in a chemical substrate.

Performing an ELISA involves at least one antibody with specificity for a particular antigen. The sample with an unknown

amount of antigen is immobilized on a solid support (usually apolystyrene microtiter plate) either non-specifically

(via adsorption to the surface) or specifically (via capture by another antibody specific to the same antigen, in a "sandwich"

ELISA). After the antigen is immobilized the detection antibody is added, forming a complex with the antigen. The detection

antibody can be covalently linked to an enzyme, or can itself be detected by a secondary antibody which is linked to an enzyme

through bioconjugation. Between each step the plate is typically washed with a mild detergent solution to remove any proteins or

antibodies that are not specifically bound. After the final wash step the plate is developed by adding an enzymatic substrate to

produce a visible signal, which indicates the quantity of antigen in the sample.

Traditional ELISA typically involves chromogenic reporters and substrates which produce some kind of observable color change

to indicate the presence of antigen or analyte. Newer ELISA-like techniques utilize fluorogenic, electrochemiluminescent,

and real-time PCR reporters to create quantifiable signals. These new reporters can have various advantages including

higher sensitivities and multiplexing [1] [2] . Technically, newer assays of this type are not strictly ELISAs as they are not "enzyme-

linked" but are instead linked to some non-enzymatic reporter. However, given that the general principles in these assays are

largely similar, they are often grouped in the same category as ELISAs.

Applications

ELISA results using S-OIV Aneuraminidase antibody at 1 μg/ml to probe the immunogenic and the corresponding seasonal

influenza A neuraminidasepeptides at 50, 10, 2 and 0 ng/ml.

Because the ELISA can be performed to evaluate either the presence of antigen or the presence of antibody in a sample, it is a

useful tool for determining serum antibody concentrations (such as with the HIV test[3] or West Nile Virus). It has also found

applications in the food industry in detecting potential food allergens such as milk, peanuts, walnuts, almonds, and eggs.[4] ELISA

can also be used in toxicology as a rapid presumptive screen for certain classes of drugs.

The ELISA was the first screening test widely used for HIV because of its high sensitivity. In an ELISA, a person's serum is

diluted 400-fold and applied to a plate to which HIV antigens are attached. If antibodies to HIV are present in the serum, they

may bind to these HIV antigens. The plate is then washed to remove all other components of the serum. A specially prepared

"secondary antibody" — an antibody that binds to other antibodies — is then applied to the plate, followed by another wash. This

secondary antibody is chemically linked in advance to an enzyme. Thus, the plate will contain enzyme in proportion to the

amount of secondary antibody bound to the plate. A substrate for the enzyme is applied, and catalysis by the enzyme leads to a

change in color or fluorescence. ELISA results are reported as a number; the most controversial aspect of this test is determining

the "cut-off" point between a positive and negative result.

A cut-off point may be determined by comparing it with a known standard. If an ELISA test is used for drug screening at

workplace, a cut-off concentration, 50 ng/mL, for example, is established, and a sample will be prepared which contains the

standard concentration of analyte. Unknowns that generate a signal that is stronger than the known sample are "positive". Those

that generate weaker signal are "negative."

History

Before the development of the ELISA, the only option for conducting an immunoassay was radioimmunoassay, a technique

usingradioactively-labeled antigens or antibodies. In radioimmunoassay, the radioactivity provides the signal which indicates

whether a specific antigen or antibody is present in the sample. Radioimmunoassay was first described in a paper by Rosalyn

Sussman Yalow and Solomon Berson published in 1960[5].

Because radioactivity poses a potential health threat, a safer alternative was sought. A suitable alternative to radioimmunoassay

would substitute a non-radioactive signal in place of the radioactive signal. When enzymes (such as peroxidase) react with

appropriate substrates (such as ABTS or 3,3’,5,5’-Tetramethylbenzidine), this causes a change in color, which is used as a signal.

However, the signal has to be associated with the presence of antibody or antigen, which is why the enzyme has to be linked to an

appropriate antibody. This linking process was independently developed by Stratis Avrameas and G.B. Pierce [6]. Since it is

necessary to remove any unbound antibody or antigen by washing, the antibody or antigen has to be fixed to the surface of the

container, i.e. the immunosorbent has to be prepared. A technique to accomplish this was published by Wide and Jerker Porath in

1966. In 1971, Peter Perlmann and Eva Engvall at Stockholm University in Sweden, and Anton Schuurs and Bauke van Weemen

in The Netherlands, independently published papers which synthesized this knowledge into methods to perform EIA/ELISA.

Types

"Indirect" ELISA

The steps of "indirect" ELISA follows the mechanism below:-

A buffered solution of the protein antigen to be tested for is added to each well of a microtiter plate, where it is given time to

adhere to the plastic through charge interactions.

A solution of non-reacting protein, such as bovine serum albumin, or casein is added to block any plastic surface in the well

that remains uncoated by the protein antigen.

Next the primary antibody, generally in the form of serum is added, which contains a mixture of the serum donor's

antibodies, of unknown concentration, some of which may bind specifically to the test antigen that is coating the well.

Afterwards, a secondary antibody is added, which will bind any antibody produced by a member of the donor's species (for

example, an antibody produced in a mouse that will bind any rabbit antibody). This secondary antibody often has an enzyme

attached to it, which has a negligible effect on the binding properties of the antibody.

A substrate for this enzyme is then added. Often, this substrate changes color upon reaction with the enzyme. The color

change shows that secondary antibody has bound to primary antibody, which strongly implies that the donor has had an

immune reaction to the test antigen. This can be helpful in a clinical setting, and in R&D.

The higher the concentration of the primary antibody that was present in the serum, the stronger the color change. Often a

spectrometer is used to give quantitative values for color strength.

The enzyme acts as an amplifier; even if only few enzyme-linked antibodies remain bound, the enzyme molecules will produce

many signal molecules. Within common-sense limitations the enzyme can go on producing color indefinitely, but the more

primary antibody is present in the donor serum, the more secondary antibody + enzyme will bind, and the faster color will

develop. A major disadvantage of the indirect ELISA is that the method of antigen immobilization is non-specific; when serum is

used as the source of test antigen, all proteins in the sample may stick to the microtiter plate well, so small concentrations of

analyte in serum must compete with other serum proteins when binding to the well surface. The sandwich or direct ELISA

provides a solution to this problem, by using a "capture" antibody specific for the test antigen to pull it out of the serum's

molecular mixture.

ELISA may be run in a qualitative or quantitative format. Qualitative results provide a simple positive or negative result (yes or

no) for a sample. The cutoff between positive and negative is determined by the analyst and may be statistical. Two or three times

the standard deviation (error inherent in a test) is often used to distinguish positive from negative samples. In quantitative ELISA,

the optical density (OD) of the sample is compared to a standard curve, which is typically a serial dilution of a known-

concentration solution of the target molecule. For example if your test sample returns an OD of 1.0, the point on your standard

curve that gave OD = 1.0 must be of the same analyte concentration as your sample.

Sandwich ELISA

A sandwich ELISA. (1) Plate is coated with a capture antibody; (2) sample is added, and any antigen present binds to capture

antibody; (3) detecting antibody is added, and binds to antigen; (4) enzyme-linked secondary antibody is added, and binds to

detecting antibody; (5) substrate is added, and is converted by enzyme to detectable form.

A less-common variant of this technique, called "sandwich" ELISA, is used to detect sample antigen. The steps are as follows:

1. Prepare a surface to which a known quantity of capture antibody is bound.

2. Block any non specific binding sites on the surface.

3. Apply the antigen-containing sample to the plate.

4. Wash the plate, so that unbound antigen is removed.

5. Apply enzyme linked primary antibodies as detection antibodies which also bind specifically to the antigen.

6. Wash the plate, so that the unbound antibody-enzyme conjugates are removed.

7. Apply a chemical which is converted by the enzyme into a color or fluorescent or electrochemical signal.

8. Measure the absorbency or fluorescence or electrochemical signal (e.g., current) of the plate wells to determine the

presence and quantity of antigen.

The image to the right includes the use of a secondary antibody conjugated to an enzyme, though technically this is not necessary

if the primary antibody is conjugated to an enzyme. However, use of a secondary-antibody conjugate avoids the expensive

process of creating enzyme-linked antibodies for every antigen one might want to detect. By using an enzyme-linked antibody

that binds the Fc region of other antibodies, this same enzyme-linked antibody can be used in a variety of situations. Without the

first layer of "capture" antibody, any proteins in the sample (including serum proteins) may competitively adsorb to the plate

surface, lowering the quantity of antigen immobilized.Use of the purified specific antibody to attach the antigen to the plastic

eliminates a need to purify the antigen from complicated mixtures before the measurement, simplifying the assay, and increasing

the specificity and the sensitivity of the assay.

A descriptive animation of the application of sandwich ELISA to home pregnancy testing can be found here.

Competitive ELISA

A third use of ELISA is through competitive binding. The steps for this ELISA are somewhat different than the first two

examples:

1. Unlabeled antibody is incubated in the presence of its antigen (Sample)

2. These bound antibody/antigen complexes are then added to an antigen coated well.

3. The plate is washed, so that unbound antibody is removed. (The more antigen in the sample, the less antibody will be

able to bind to the antigen in the well, hence "competition.")

4. The secondary antibody, specific to the primary antibody is added. This second antibody is coupled to the enzyme.

5. A substrate is added, and remaining enzymes elicit a chromogenic or fluorescent signal.

For competitive ELISA, the higher the sample antigen concentration, the weaker the eventual signal. The major advantage of a

competitive ELISA is the ability to use crude or impure samples and still selectively bind any antigen that may be present.

(Note that some competitive ELISA kits include enzyme-linked antigen rather than enzyme-linked antibody. The labeled antigen

competes for primary antibody binding sites with your sample antigen (unlabeled). The more antigen in the sample, the less

labeled antigen is retained in the well and the weaker the signal).

Commonly the antigen is not first positioned in the well.Multiple and Portable ELISA (M&P ELISA)(ELISA Reverse in

published papers)

A new technique (EP 1 499 894 B1 in EPO Bulletin 25.02.209 N. 2009/09; USPTO 7510687 in USPTO Bulletin 31.03.2009; ZL

03810029.0 in SIPO PRC Bulletin 08.04.2009) uses a solid phase made up of an immunosorbent polystyrene rod with 8-12

protruding ogives. The entire device is immersed in a test tube containing the collected sample and the following steps (washing,

incubation in conjugate and incubation in chromogenous) are carried out by dipping the ogives in microwells of standard

microplates pre-filled with reagents.

The advantages of this technique are as follows:

1. The ogives can each be sensitized to a different reagent, allowing the simultaneous detection of different antibodies and

/ or different antigens for multi-target assays;

2. The sample volume can be increased to improve the test sensitivity in clinical (saliva, urine), food (bulk milk, pooled

eggs) and environmental (water) samples;

3. One ogive is left unsensitized to measure the non-specific reactions of the sample;

4. The use of laboratory supplies for dispensing sample aliquots, washing solution and reagents in microwells is not

required, facilitating the deveopment of ready-to-use lab-kits and on-site kits.

Complement fixation test

The complement fixation test is an immunological medical test that can be used to detect the presence of either

specific antibody or specific antigen in a patient's serum. It was widely used to diagnose infections, particularly with microbes

that are not easily detected by culture methods, and in rheumatic diseases. However, in clinical diagnostics labs it has been

largely superseded by other serological methods such as ELISA and by DNA-based methods of pathogen detection,

particularly PCR.

Process

The CF test uses sheep red blood cells (sRBC), pre-bound by anti-sRBC antibody, and serum (usually from guinea pig) as a

source ofcomplement, which is a system of serum proteins that react with antigen-antibody complexes. If this reaction occurs on

a cell surface, it will result in the formation of trans-membrane pores and therefore destruction of the cell. Accordingly, if the

antibody-sensitized sRBC are brought into contact with active complement, they will undergo disintegration (hemolysis).

Complement will also react with antigen-antibody complexes in solution. The complement is thereby expended and can no longer

trigger hemolysis; inhibition of complement hemolysis therefore indicates the presence of antigen-antibody complexes. A

patient's serum containing a certain antibody (specific for, say, rubella virus) will yield antigen-antibody complexes after addition

of the corresponding antigen (inactivated rubella virus in our example). Complement added to the mixture will be consumed, and

sensitized sRBC added subsequently will not undergo hemolysis. Therefore, absence of hemolysis constitutes a positive CF test

(patient's serum contains the antibody of interest).

Testing for antigen

While detection of antibodies is the more common test format, it is equally possible to test for the presence of antigen. In this

case, the patient's serum is supplemented with specific antibody to induce formation of complexes; addition of complement and

indicator sRBC is performed as before.

Quantitative testing

The test can be made quantitative by setting up a series of dilutions of patient serum and determining the highest dilution factor

that will still yield a positive CF test. This dilution factor corresponds to the titer

Western blot

Western blot analysis of proteins separated by SDS-PAGE.[1]

The Western blot (alternatively, protein immunoblot) is an analytical technique used to detect specific proteins in a given

sample of tissue homogenate or extract. It uses gel electrophoresis to separate native or denatured proteins by the length of the

polypeptide (denaturing conditions) or by the 3-D structure of the protein (native/ non-denaturing conditions). The proteins are

then transferred to a membrane (typically nitrocellulose or PVDF), where they are probed (detected) using antibodies specific to

the target protein.

There are now many reagent companies that specialize in providing antibodies (both monoclonaland polyclonal antibodies)

against tens of thousands of different proteins.[4] Commercial antibodies can be expensive, although the unbound antibody can be

reused between experiments. This method is used in the fields of molecular biology, biochemistry, immunogenetics and other

molecular biology disciplines.

Other related techniques include using antibodies to detect proteins in tissues and cells byimmunostaining and enzyme-linked

immunosorbent assay (ELISA).

The method originated from the laboratory of George Stark at Stanford. The name Western blotwas given to the technique by W.

Neal Burnette[5] and is a play on the name Southern blot, a technique for DNA detection developed earlier by Edwin Southern.

Detection of RNA is termednorthern blotting and the detection of post-translational modification of protein is termed eastern

blotting.

Steps in a Western blot

Tissue preparation

Samples may be taken from whole tissue or from cell culture. In most cases, solid tissues are first broken down mechanically

using ablender (for larger sample volumes), using a homogenizer (smaller volumes), or by sonication. Cells may also be broken

open by one of the above mechanical methods. However, it should be noted that bacteria, virus or environmental samples can be

the source of protein and thus Western blotting is not restricted to cellular studies only.

Assorted detergents, salts, and buffers may be employed to encourage lysis of cells and to solubilize

proteins. Protease and phosphataseinhibitors are often added to prevent the digestion of the sample by its own enzymes. Tissue

preparation is often done at cold temperatures to avoid protein denaturing.

A combination of biochemical and mechanical techniques – including various types of filtration and centrifugation – can be used

to separate different cell compartments and organelles.

Gel electrophoresis

The proteins of the sample are separated using gel electrophoresis. Separation of proteins may be by isoelectric

point (pI), molecular weight, electric charge, or a combination of these factors. The nature of the separation depends on the

treatment of the sample and the nature of the gel. This is a very useful way to determine a protein.

By far the most common type of gel electrophoresis employs polyacrylamide gels and buffers loaded with sodium dodecyl

sulfate (SDS).SDS-PAGE (SDS polyacrylamide gel electrophoresis) maintains polypeptides in a denatured state once they have

been treated with strong reducing agents to remove secondary and tertiary structure (e.g. disulfide bonds [S-S] to sulfhydryl

groups [SH and SH]) and thus allows separation of proteins by their molecular weight. Sampled proteins become covered in the

negatively charged SDS and move to the positively charged electrode through the acrylamide mesh of the gel. Smaller proteins

migrate faster through this mesh and the proteins are thus separated according to size (usually measured in kilodaltons, kDa). The

concentration of acrylamide determines the resolution of the gel - the greater the acrylamide concentration the better the

resolution of lower molecular weight proteins. The lower the acrylamide concentration the better the resolution of higher

molecular weight proteins. Proteins travel only in one dimension along the gel for most blots.

Samples are loaded into wells in the gel. One lane is usually reserved for a marker or ladder, a commercially available mixture of

proteins having defined molecular weights, typically stained so as to form visible, coloured bands. When voltage is applied along

the gel, proteins migrate into it at different speeds. These different rates of advancement (different electrophoretic mobilities)

separate into bands within eachlane.

It is also possible to use a two-dimensional (2-D) gel which spreads the proteins from a single sample out in two dimensions.

Proteins are separated according to isoelectric point (pH at which they have neutral net charge) in the first dimension, and

according to their molecular weight in the second dimension.

Transfer

In order to make the proteins accessible to antibody detection, they are moved from within the gel onto a membrane made

of nitrocellulose orpolyvinylidene difluoride (PVDF). The membrane is placed on top of the gel, and a stack of filter papers

placed on top of that. The entire stack is placed in a buffer solution which moves up the paper by capillary action, bringing the

proteins with it. Another method for transferring the proteins is called electroblotting and uses an electric current to pull proteins

from the gel into the PVDF or nitrocellulose membrane. The proteins move from within the gel onto the membrane while

maintaining the organization they had within the gel. As a result of this "blotting" process, the proteins are exposed on a thin

surface layer for detection (see below). Both varieties of membrane are chosen for their non-specific protein binding properties

(i.e. binds all proteins equally well). Protein binding is based upon hydrophobic interactions, as well as charged interactions

between the membrane and protein. Nitrocellulose membranes are cheaper than PVDF, but are far more fragile and do not stand

up well to repeated probings.

The uniformity and overall effectiveness of transfer of protein from the gel to the membrane can be checked by staining the

membrane withCoomassie Brilliant Blue or Ponceau S dyes. Ponceau S is the more common of the two, due to Ponceau S's

higher sensitivity and its water solubility makes it easier to subsequently destain and probe the membrane as described below. [6]

Blocking

Since the membrane has been chosen for its ability to bind protein and as both antibodies and the target are proteins, steps must

be taken to prevent interactions between the membrane and the antibody used for detection of the target protein. Blocking of non-

specific binding is achieved by placing the membrane in a dilute solution of protein - typically 3-5% Bovine serum

albumin (BSA) or non-fat dry milk (both are inexpensive) in Tris-Buffered Saline (TBS), with a minute percentage of detergent

such as Tween 20 or Triton X-100. The protein in the dilute solution attaches to the membrane in all places where the target

proteins have not attached. Thus, when the antibody is added, there is no room on the membrane for it to attach other than on the

binding sites of the specific target protein. This reduces "noise" in the final product of the Western blot, leading to clearer results,

and eliminates false positives.

Detection

During the detection process the membrane is "probed" for the protein of interest with a modified antibody which is linked to a

reporter enzyme, which when exposed to an appropriate substrate drives a colourimetric reaction and produces a colour. For a

variety of reasons, this traditionally takes place in a two-step process, although there are now one-step detection methods

available for certain applications.

Two steps

Primary antibody

Antibodies are generated when a host species or immune cell culture is exposed to the protein of interest (or a part thereof).

Normally, this is part of the immune response, whereas here they are harvested and used as sensitive and specific detection tools

that bind the protein directly.

After blocking, a dilute solution of primary antibody (generally between 0.5 and 5 micrograms/mL) is incubated with the

membrane under gentle agitation. Typically, the solution is composed of buffered saline solution with a small percentage of

detergent, and sometimes with powdered milk or BSA. The antibody solution and the membrane can be sealed and incubated

together for anywhere from 30 minutes to overnight. It can also be incubated at different temperatures, with warmer temperatures

being associated with more binding, both specific (to the target protein, the "signal") and non-specific ("noise").

Secondary antibody

After rinsing the membrane to remove unbound primary antibody, the membrane is exposed to another antibody, directed at a

species-specific portion of the primary antibody. Antibodies come from animal sources (or animal sourced hybridoma cultures);

an anti-mouse secondary will bind to almost any mouse-sourced primary antibody, which allows some cost savings by allowing

an entire lab to share a single source of mass-produced antibody, and provides far more consistent results. This is known as a

secondary antibody, and due to its targeting properties, tends to be referred to as "anti-mouse," "anti-goat," etc. The secondary

antibody is usually linked to biotin or to a reporter enzyme such as alkaline phosphatase or horseradish peroxidase. This means

that several secondary antibodies will bind to one primary antibody and enhance the signal.

Most commonly, a horseradish peroxidase-linked secondary is used to cleave a chemiluminescent agent, and the reaction product

producesluminescence in proportion to the amount of protein. A sensitive sheet of photographic film is placed against the

membrane, and exposure to the light from the reaction creates an image of the antibodies bound to the blot. A cheaper but less

sensitive approach utilizes a 4-chloronaphthol stain with 1% hydrogen peroxide; reaction of peroxide radicals with 4-

chloronaphthol produces a dark brown stain that can be photographed without using specialized photographic film.

As with the ELISPOT and ELISA procedures, the enzyme can be provided with a substrate molecule that will be converted by

the enzyme to a colored reaction product that will be visible on the membrane (see the figure below with blue bands).

Another method of secondary antibody detection utilizes a near-infrared (NIR) fluorophore-linked antibody. Light produced from

the excitation of a fluorescent dye is static, making fluorescent detection a more precise and accurate measure of the difference in

signal produced by labeled antibodies bound to proteins on a Western blot. Proteins can be accurately quantified because the

signal generated by the different amounts of proteins on the membranes is measured in a static state, as compared to

chemiluminescence, in which light is measured in a dynamic state.[7]

A third alternative is to use a radioactive label rather than an enzyme coupled to the secondary antibody, such as labeling an

antibody-binding protein like Staphylococcus Protein A or Streptavidin with a radioactive isotope of iodine. Since other methods

are safer, quicker, and cheaper, this method is now rarely used; however, an advantage of this approach is the sensitivity of auto-

radiography based imaging, which enables highly accurate protein quantification when combined with optical software (e.g.

Optiquant).

One step

Historically, the probing process was performed in two steps because of the relative ease of producing primary and secondary

antibodies in separate processes. This gives researchers and corporations huge advantages in terms of flexibility, and adds an

amplification step to the detection process. Given the advent of high-throughput protein analysis and lower limits of detection,

however, there has been interest in developing one-step probing systems that would allow the process to occur faster and with

less consumables. This requires a probe antibody which both recognizes the protein of interest and contains a detectable label,

probes which are often available for known protein tags. The primary probe is incubated with the membrane in a manner similar

to that for the primary antibody in a two-step process, and then is ready for direct detection after a series of wash steps.

Western blot using radioactive detection system

Analysis

After the unbound probes are washed away, the Western blot is ready for detection of the probes that are labeled and bound to the

protein of interest. In practical terms, not all Westerns reveal protein only at one band in a membrane. Size approximations are

taken by comparing the stained bands to that of the marker or ladder loaded during electrophoresis. The process is repeated for a

structural protein, such as actin or tubulin, that should not change between samples. The amount of target protein is indexed to

the structural protein to control between groups. This practice ensures correction for the amount of total protein on the membrane

in case of errors or incomplete transfers.

Colorimetric detection

The colorimetric detection method depends on incubation of the Western blot with a substrate that reacts with the reporter

enzyme (such asperoxidase) that is bound to the secondary antibody. This converts the soluble dye into an insoluble form of a

different color that precipitates next to the enzyme and thereby stains the membrane. Development of the blot is then stopped by

washing away the soluble dye. Protein levels are evaluated through densitometry (how intense the stain is) or spectrophotometry.

Chemiluminescent detection

Chemiluminescent detection methods depend on incubation of the Western blot with a substrate that will luminesce when

exposed to the reporter on the secondary antibody. The light is then detected by photographic film, and more recently by CCD

cameras which capture a digital image of the Western blot. The image is analysed by densitometry, which evaluates the relative

amount of protein staining and quantifies the results in terms of optical density. Newer software allows further data analysis such

as molecular weight analysis if appropriate standards are used.

Radioactive detection

Radioactive labels do not require enzyme substrates, but rather allow the placement of medical X-ray film directly against the

Western blot which develops as it is exposed to the label and creates dark regions which correspond to the protein bands of

interest (see image to the right). The importance of radioactive detections methods is declining [citation needed], because it is very

expensive, health and safety risks are high, and ECL (enhanced chemiluminescence) provides a useful alternative.

Fluorescent detection

The fluorescently labeled probe is excited by light and the emission of the excitation is then detected by a photosensor such as

CCD camera equipped with appropriate emission filters which captures a digital image of the Western blot and allows further

data analysis such as molecular weight analysis and a quantitative Western blot analysis. Fluorescence is considered to be among

the most sensitive detection methods for blotting analysis.

Secondary probing

One major difference between nitrocellulose and PVDF membranes relates to the ability of each to support "stripping" antibodies

off and reusing the membrane for subsequent antibody probes. While there are well-established protocols available for stripping

nitrocellulose membranes, the sturdier PVDF allows for easier stripping, and for more reuse before background noise limits

experiments. Another difference is that, unlike nitrocellulose, PVDF must be soaked in 95% ethanol, isopropanol or methanol

before use. PVDF membranes also tend to be thicker and more resistant to damage during use.

2-D gel electrophoresis

2-dimensional SDS-PAGE uses the principles and techniques outlined above. 2-D SDS-PAGE, as the name suggests, involves

the migration of polypeptides in 2 dimensions. For example, in the first dimension polypeptides are separated according

to isoelectric point, while in the second dimension polypeptides are separated according to their molecular weight. The isoelectric

point of a given protein is determined by the relative number of positively (e.g. lysine and arginine) and negatively (e.g.

glutamate and aspartate) charged amino acids, with negatively charged amino acids contributing to a high isoelectric point and

positively charged amino acids contributing to a low isoelectric point. Samples could also be separated first under nonreducing

conditions using SDS-PAGE and under reducing conditions in the second dimension, which breaks apart disulfide bonds that

hold subunits together. SDS-PAGE might also be coupled with urea-PAGE for a 2-dimensional gel.

In principle, this method allows for the separation of all cellular proteins on a single large gel. A major advantage of this method

is that it often distinguishes between different isoforms of a particular protein - e.g. a protein that has been phosphorylated (by

addition of a negatively charged group). Proteins that have been separated can be cut out of the gel and then analysed by mass

spectrometry, which identifies the protein.

Please refer to reference articles for examples of the application of 2-D SDS PAGE.

[edit]Medical diagnostic applications

The confirmatory HIV test employs a Western blot to detect anti-HIV antibody in a human serum sample. Proteins

from known HIV-infected cells are separated and blotted on a membrane as above. Then, the serum to be tested is applied in

the primary antibody incubation step; free antibody is washed away, and a secondary anti-human antibody linked to an

enzyme signal is added. The stained bands then indicate the proteins to which the patient's serum contains antibody.

A Western blot is also used as the definitive test for Bovine spongiform encephalopathy (BSE, commonly referred to as

'mad cow disease').

Some forms of Lyme disease testing employ Western blotting.

Western blot can also be used as a confirmatory test for Hepatitis B infection.

In veterinary medicine, Western blot is sometimes used to confirm FIV+ status in cats.

DIRECT EXAMINATION:-

. When examining foods, the possibility of detecting the presence of microorganisms by looking at a sample directly under the microscope should not be missed.

. A small amount of material can be mounted and teased out in a drop of water on a slide, covered with a cover slip, and examined.

Direct-to-Consumer genetic testing

Direct-to-Consumer (DTC) genetic testing is a type of genetic test that is accessible directly to the consumer without having to go

through a health care professional. Usually, to obtain a genetic test, health care professionals such as doctors acquire the

permission of the patient and order the desired test. DTC genetic tests, however, allow consumers to bypass this process and

order one themselves. There are a variety of DTC tests, ranging from testing for breast cancer alleles to mutations linked to cystic

fibrosis. Benefits of DTC testing are the accessibility of tests to consumers, promotion of proactive healthcare and the privacy of

genetic information. Possible additional risks of DTC testing are the lack of governmental regulation and the potential

misinterpretation of genetic information.

3.Explain the culture techniques in detail.

cultural tecniques:-

The full microbiological examination usually requires that individual viable propagules are encouraged to multiply in liquid media or on the surface, or with in the matrix, of a medium solidified with agar.

Cell cultureFrom Wikipedia, the free encyclopedia

Jump to: navigation, search

Epithelial cells in culture, stained for keratin (red) and DNA (green)

Cell culture is the complex process by which cells are grown under controlled conditions. In practice, the term "cell culture" has come to refer to the culturing of cells derived from multicellular eukaryotes, especially animal cells. However, there are also cultures of plants, fungi and microbes, including viruses, bacteria and protists. The historical development and methods of cell culture are closely interrelated to those of tissue culture and organ culture.

Animal cell culture became a common laboratory technique in the mid-1900s,[1] but the concept of maintaining live cell lines separated from their original tissue source was discovered in the 19th century.

History

The 19th-century English physiologist Sydney Ringer developed salt solutions containing the chlorides of sodium, potassium, calcium and magnesium suitable for maintaining the beating of an isolated animal heart outside of the body.[1] In 1885 Wilhelm Roux removed a portion of the medullary plate of an embryonic chicken and maintained it in a warm saline solution for several days, establishing the principle of tissue culture.[3] Ross Granville Harrison, working at Johns Hopkins Medical School and then at Yale University, published results of his experiments from 1907–1910, establishing the methodology of tissue culture.[4]

Cell culture techniques were advanced significantly in the 1940s and 1950s to support research in virology. Growing viruses in cell cultures allowed preparation of purified viruses for the manufacture of vaccines. The injectable polio vaccine developed by

Jonas Salk was one of the first products mass-produced using cell culture techniques. This vaccine was made possible by the cell culture research of John Franklin Enders, Thomas Huckle Weller, and Frederick Chapman Robbins, who were awarded a Nobel Prize for their discovery of a method of growing the virus in monkey kidney cell cultures.

Concepts in mammalian cell cultureIsolation of cells

Cells can be isolated from tissues for ex vivo culture in several ways. Cells can be easily purified from blood, however only the white cells are capable of growth in culture. Mononuclear cells can be released from soft tissues by enzymatic digestion with enzymes such as collagenase, trypsin, or pronase, which break down the extracellular matrix. Alternatively, pieces of tissue can be placed in growth media, and the cells that grow out are available for culture. This method is known as explant culture.

Cells that are cultured directly from a subject are known as primary cells. With the exception of some derived from tumors, most primary cell cultures have limited lifespan. After a certain number of population doublings (called the Hayflick limit) cells undergo the process of senescence and stop dividing, while generally retaining viability.

An established or immortalised cell line has acquired the ability to proliferate indefinitely either through random mutation or deliberate modification, such as artificial expression of the telomerase gene. There are numerous well established cell lines representative of particular cell types.

Maintaining cells in culture

Cells are grown and maintained at an appropriate temperature and gas mixture (typically, 37°C, 5% CO2 for mammalian cells) in a cell incubator. Culture conditions vary widely for each cell type, and variation of conditions for a particular cell type can result in different phenotypes being expressed.

Aside from temperature and gas mixture, the most commonly varied factor in culture systems is the growth medium. Recipes for growth media can vary in pH, glucose concentration, growth factors, and the presence of other nutrients. The growth factors used to supplement media are often derived from animal blood, such as calf serum. One complication of these blood-derived ingredients is the potential for contamination of the culture with viruses or prions, particularly in biotechnology medical applications. Current practice is to minimize or eliminate the use of these ingredients wherever possible, but this cannot always be accomplished. Alternative strategies involve sourcing the animal blood from countries with minimum BSE/TSE risk such as Australia and New Zealand, and using purified nutrient concentrates derived from serum in place of whole animal serum for cell culture.[5]

Plating density (number of cells per volume of culture medium) plays a critical role for some cell types. For example, a lower plating density makes granulosa cells exhibit estrogen production, while a higher plating density makes them appear as progesterone producing theca lutein cells.[6]

Cells can be grown in suspension or adherent cultures. Some cells naturally live in suspension, without being attached to a surface, such as cells that exist in the bloodstream. There are also cell lines that have been modified to be able to survive in suspension cultures so that they can be grown to a higher density than adherent conditions would allow. Adherent cells require a surface, such as tissue culture plastic or microcarrier, which may be coated with extracellular matrix components to increase adhesion properties and provide other signals needed for growth and differentiation. Most cells derived from solid tissues are adherent. Another type of adherent culture is organotypic culture which involves growing cells in a three-dimensional environment as opposed to two-dimensional culture dishes. This 3D culture system is biochemically and physiologically more similar to in vivo tissue, but is technically challenging to maintain because of many factors (e.g. diffusion).

Cell line cross-contamination

Cell line cross-contamination can be a problem for scientists working with cultured cells. Studies suggest that anywhere from 15–20% of the time, cells used in experiments have been misidentified or contaminated with another cell line. [7][8][9] Problems with cell line cross contamination have even been detected in lines from the NCI-60 panel, which are used routinely for drug-screening studies.[10][11] Major cell line repositories including the American Type Culture Collection (ATCC) and the German Collection of Microorganisms and Cell Cultures (DSMZ) have received cell line submissions from researchers that were misidentified by the researcher.[10][12] Such contamination poses a problem for the quality of research produced using cell culture lines, and the major repositories are now authenticating all cell line submissions.[13] ATCC uses short tandem repeat (STR) DNA fingerprinting to authenticate its cell lines.[14]

To address this problem of cell line cross-contamination, researchers are encouraged to authenticate their cell lines at an early passage to establish the identity of the cell line. Authentication should be repeated before freezing cell line stocks, every two months during active culturing and before any publication of research data generated using the cell lines. There are many methods for identifying cell lines including isoenzyme analysis, human lymphocyte antigen (HLA) typing, Chromosomal analysis, Karyotyping, Morphology and STR analysis.[14]

One significant cell-line cross contaminant is the immortal HeLa cell line.

Manipulation of cultured cells

As cells generally continue to divide in culture, they generally grow to fill the available area or volume. This can generate several issues:

Nutrient depletion in the growth media Accumulation of apoptotic/necrotic (dead) cells.

Cell-to-cell contact can stimulate cell cycle arrest, causing cells to stop dividing known as contact inhibition or senescence.

Cell-to-cell contact can stimulate cellular differentiation.

Among the common manipulations carried out on culture cells are media changes, passaging cells, and transfecting cells. These are generally performed using tissue culture methods that rely on sterile technique. Sterile technique aims to avoid contamination with bacteria, yeast, or other cell lines. Manipulations are typically carried out in a biosafety hood or laminar flow cabinet to exclude contaminating micro-organisms. Antibiotics (e.g. penicillin and streptomycin) and antifungals (e.g. Amphotericin B) can also be added to the growth media.

As cells undergo metabolic processes, acid is produced and the pH decreases. Often, a pH indicator is added to the medium in order to measure nutrient depletion.

Media changes

In the case of adherent cultures, the media can be removed directly by aspiration and replaced.

Passaging cells

Passaging (also known as subculture or splitting cells) involves transferring a small number of cells into a new vessel. Cells can be cultured for a longer time if they are split regularly, as it avoids the senescence associated with prolonged high cell density. Suspension cultures are easily passaged with a small amount of culture containing a few cells diluted in a larger volume of fresh media. For adherent cultures, cells first need to be detached; this is commonly done with a mixture of trypsin-EDTA, however other enzyme mixes are now available for this purpose. A small number of detached cells can then be used to seed a new culture.

Transfection and transduction

Another common method for manipulating cells involves the introduction of foreign DNA by transfection. This is often performed to cause cells to express a protein of interest. More recently, the transfection of RNAi constructs have been realized as a convenient mechanism for suppressing the expression of a particular gene/protein. DNA can also be inserted into cells using viruses, in methods referred to as transduction, infection or transformation. Viruses, as parasitic agents, are well suited to introducing DNA into cells, as this is a part of their normal course of reproduction.

[edit] Established human cell lines

One of the earliest human cell lines, descended from Henrietta Lacks, who died of the cancer that those cells originated from, the cultured HeLa cells shown here have been stained with Hoechst turning their nuclei blue.

Cell lines that originate with humans have been somewhat controversial in bioethics, as they may outlive their parent organism and later be used in the discovery of lucrative medical treatments. In the pioneering decision in this area, the Supreme Court of California held in Moore v. Regents of the University of California that human patients have no property rights in cell lines derived from organs removed with their consent.

A SELECTION OF MEDIA COMMONLY USED IN FOOD MICROBIOLOGY:

MEDIUM USE

1. Plate count agar Aerobic mesophilic count

2. Mac Conkey broth MPN of coliforms in water

3. Brilliant Green/Lactose/ Bile broth MPN of coliforms in food

4. Violet red/ bile/Glucose agar Enumeration of Enterobacteriaceae.

5. Crystal violet /Azide / Blood agar Enumeration of faecal Streptococci.

6. Baird- Parker agar Enumeration of S. aureus

7. Vassiliadis broth Selection enrichment of Salmonella.

8. Thiosulfate / bile/ citrate/ Sucrose agar Isolation of Vibrios

9. Rose Bengal/ Chloramphenicol agar Enumeration of moulds and yeasts

10. Mac Conkey agar E. coli .

4.Explain the Enumeration methods in detail.

Enumeration methods:-

Plate counts-

It has already been suggested that to count microorganisms in a food sample by direct microscopy has a limited sensitivity because of the very small sample size in the field of view at the magnification needed to see microorganisms, especially bacteria.

In a normal routine laboratory the most sensitive methods of detecting the presence of a viable bacterium is to allow it to amplify itself to form a visible colony.

This forms the basis of the traditional pour plate and spread plate and most probable number counts.

5.Explain the Alternative methods in detail.

Alternative methods- .Cultural methods are relatively labour intensive and require time for adequate growth to occur. . Many food microbiologists also consider that the traditional enumeration methods are not only too slow but lead to an

over dependence on the significance of numbers of colony forming units. . A number of methods have been developed which aim to give answer of redox to as “Rapid methods”.

Dye- reduction test:-

A group of tests which have been used for some time in the dairy industry dependent on the response of a number of redox dye to the presence of metabolically active microorganisms.

They are relatively simple and rapid to carry out at low cost. The redox dyes are able to take up electrons from an active biological system and this results in a

change of colour.

Dye Reduction Tests: Methylene Blue and Resazurin.

Methylene Blue Reduction Test

The methylene blue reduction test is based on the fact that the color imparted to milk by the addition of a dye such as methylene blue will disappear more or less quickly. The removal of the oxygen from milk and the formation of reducing substances during bacterial metabolism causes the color to disappear. The agencies responsible for the oxygen consumption are the bacteria. Though certain species of bacteria have considerably more influence than others, it is generally assumed that the greater the number of bacteria in milk, the quicker will the oxygen be consumed, and in turn the sooner will the color disappear. Thus, the time of reduction is taken as a measure of the number of organisms in milk although actually it is likely that it is more truly a measure of the total metabolic reactions proceeding at the cell surface of the bacteria.

The methylene blue reduction test has lost much of its popularity because of its low correlation with other bacterial procedures. This is true particularly in those samples which show extensive multiplication of the psychrotropic species.

Apparatus.–The necessary equipment consists of test tubes with rubber stoppers, a pipette or dipper graduated to deliver 10 ml of milk and a water bath for maintaining the samples at 35o to 37oC. The bath should contain a volume of water sufficient to heat the samples to 35o C within 10 minutes after the tubes enter the water and should have some means of protecting the samples from light during the incubation period. If a hot-air chamber is used, the samples should be heated to 35o C in a water bath since warm air would heat the milk too slowly.

The dry tablets contain methylene blue thiocyanate and may be obtained from any of the usual laboratory supply houses. They should be certified by the Commission on Standardization of Biological Stains. The solution is prepared by autoclaving or momentarily boiling 200 ml of distilled water in a light resistant (amber) stoppered flask and then adding one methylene blue

tablet to the flask of hot water. The tablet should be completely dissolved before the solution is cooled. The solution may be stored in the stoppered, amber flask or an amber bottle in the dark. Fresh solution should be prepared weekly.

Procedure in Testing.–The following procedures are recommended.

(1) Sterilize all glassware and rubber stoppers either in an autoclave or in boiling water. Be sure all glassware is chemically clean.

(2) Measure 1 ml of the methylene blue thiocyanate solution into a test tube.

(3) Add 10 ml of milk and stopper.

(4) Tubes may be placed in the water bath immediately or may be stored in the refrigerator at 0o to 4o C for a more convenient time of incubation. When ready to perform the test, the temperature of the samples should be brought to 35o C within 10 minutes.

(5) When temperature reaches 36o C, slowly invert tubes a few times to assure uniform creaming. Do not shake tubes. Record this time as the beginning of the incubation period. Cover to keep out light.

(6) Check samples for decolorization after 30 minutes of incubation. Make subsequent readings at hourly intervals thereafter.

(7) After each reading, remove decolorized tubes and then slowly make one complete inversion of remaining tubes.

(8) Record reduction time in whole hours between last inversion and decolorization. For example, if the sample were still blue after L 5 hours but was decolorized (white) at the 2.5 hour reading, the methylene blue reduction time would be recorded as 2 hours. Decolorization is considered complete when four-fifths of the color has disappeared.

Classification.–The suggested classification is listed.

Class 1. Excellent, not decolorized in 8 hours.

Class 2. Good, decolorized in less than 8 hours but not less than 6 hours.

Class 3. Fair, decolorized in less than 6 hours but not less than 2 hours.

Class 4. Poor, decolorized in less than 2 hours.

Factors Affecting the Test.–Many factors affect the methylene blue reduction test and therefore the steps of operation should be uniform.

Since the oxygen content must be used up before the color disappears, any manipulation that increases the oxygen affects the test. Cold milk holds more oxygen than warm milk; pouring milk back and forth from one container to another increases the amount, and at milking time much oxygen may be absorbed.

The kind of organisms affect the rate of reduction. The coliforms appear to be the most rapidly reducing organisms, closely followed by Streptococcus lactis, some of the faecal Streptococci, and certain micrococci. Thermoduric and psychrotrophic bacteria reduce methylene blue very slowly if at all. A large number of leucocytes affect the reduction time materially.

Light hastens reduction and therefore the tests should be kept covered. The concentration of the dye should be uniform as an increased concentration lengthens the time of reduction. Increasing the incubation temperature augments the activity of the bacteria and therefore shortens the reduction time.

The creaming of the test samples causes a number of organisms to be removed from the body of the milk and brought to the surface with the rising fat. This factor causes variations in the reduction time, since the bacteria are not evenly distributed. The accuracy of the test i s increased, reduction time shortened and decolorization more uniform if the samples are periodically inverted during incubation.

The Resazurin Test

The resazurin test is conducted similar to the methylene blue reduction test with the judgement of quality based either on the color produced after a stated period of incubation or on the time required to reduce the dye to a given end-point. Numerous modifications have been proposed. The two most commonly used are the "one-hour test" and the "triple-reading test" taken after one, two, and three hours of incubation. Other modifications have value in specific applications.

The procedure for making the resazurin test is as follows: Prepare resazurin solution by dissolving one resazurin tablet (dye content/ tablet, approximately 11 mg, certified by Biological Stain Commission) in 200 ml of hot distilled water as was done in the methylene blue test. Place one ml of dye solution in a sterile test tube, then add 10 ml of sample. Stopper the tube, place in the incubator and, when the temperature reaches 36o C, invert to mix the milk and dye. Incubate at 36o C. Tubes are examined and classified at the end of an hour in the "one-hour test" or at the end of three successive hourly intervals in the "triplereading test." The following relationships of color and quality are generally accepted:

Color of Sample: Quality of Milk

1. Blue (no color change): Excellent

2, Blue to deep mauve: Good

3. Deep mauve to deep pink: Fair

4. Deep pink to whitish pink: Poor

5. White: Bad

The resazurin test may be a valuable time saving tool if properly conducted and intelligently interpreted, but should be supplemented by microscopic examination.

Results on the reliability of the resazurin tests are conflicting. One study in comparing the resazurin test with the Breed microscopic method on 235 samples found the test reliable. Other reports state that the resazurin test is an unreliable index of bacteriological quality in milk. A major criticism of the method is that the resazurin reduction time of refrigerated bottled milk at either 20o or 37o C is much too long to be of any value in evaluating bacteriological spoilage of stored milk.

Standard Methods notes that under no circumstances should results of either methylene blue or resazurin tests be reported in terms of bacterial numbers. The two dye reduction procedures are described in more detail in Chapter 15 of the Thirteenth Edition of Standard Methods compiled by the American Public Health Association.

ELECTRICAL METHODS

Electrical methods employ a variety of measurements of the effects of electrical current flow within the Earth. The phenomena that can be measured include current flow, electrical potential (voltages), and electromagnetic fields. A summary of the better-known electrical methods is given below. In this set of notes we will consider only one of these methods, the DC resistivity method, in greater detail.

DC Resistivity - This is an active method that employs measurements of electrical potential associated with subsurface electrical current flow generated by a DC, or slowly varying AC, source. Factors that affect the measured potential, and

thus can be mapped using this method, include the presence and quality of pore fluids and clays. Our discussions will focus solely on this method.

Induced Polarization (IP) - This is an active method that is commonly done in conjunction with DC Resistivity. It employs measurements of the transient (short-term) variations in potential as the current is initially applied or removed from the ground, or alternatively the variation in the response as the AC frequency is changed. It has been observed that when a current is applied to the ground, the ground behaves much like a capacitor, storing some of the applied current as a charge that is dissipated upon removal of the current. In this process, both capacitative and electrochemical effects are responsible. IP is commonly used to detect concentrations of clay, and electrically conductive metallic mineral grains.

Self Potential (SP) - This is a passive method that employs measurements of naturally occurring electrical potentials commonly associated with shallow electrical conductors, such as sulfide ore bodies. Measurable electrical potentials have also been observed in association with groundwater flow and certain biologic processes. The only equipment needed for conducting an SP survey is a high-impedance voltmeter and some means of making good electrical contact to the ground.

Electromagnetic (EM) - This is an active method that employs measurements of a time-varying magnetic field generated by induction through current flow within the earth. In this technique, a time-varying magnetic field is generated at the surface of the earth that produces a time-varying electrical current in the earth through induction. A receiver is deployed that compares the magnetic field produced by the current-flow in the earth to that generated at the source. EM is used for locating conductive base-metal deposits, for locating buried pipes and cables, for the detection of unexploded ordnance, and for near-surface geophysical mapping.

Magnetotelluric (MT) - This is a passive method that employs measurements of naturally occurring electrical currents, telluric currents, generated by magnetic induction from electrical currents in the ionosphere. This method can be used to determine electrical properties of materials at relatively great depths (down to and including the mantle) inside the Earth. In this technique, a time variation in electrical potential is measured at a base station and at survey stations. Differences in the recorded signal are used to estimate subsurface distribution of electrical resistivity.

ATP DETERMINATION

ATP determination

ATP determination using the time stable bioluminescent luciferase assay. This assay is optimized for applications where ATP concentrations ranging from 10 nM up to 10 µM are determined. The luminescence signal is stable for at least 4 hours.

The luciferase bioluminescent assay includes thermostable firefly luciferase, D-Luciferin as substrate and appropriate buffer solutions optimized for sensitive ATP quantification.

The production of ATP is vital for muscle contraction, chemiosmotic homeostasis, and normal cellular function. Many studies have measured ATP content or qualitative changes in ATP production, but few have quantified ATP production in vivo in isolated mitochondria. Because of the importance of understanding the energy capacity of mitochondria in biology, physiology, cellular dysfunction, and ultimately, disease pathologies and normal aging, we modified a commercially available bioluminescent ATP determination assay for quantitatively measuring ATP content and rate of ATP production in isolated mitochondria. The bioluminescence assay is based on the reaction of ATP with recombinant firefly luciferase and its substrate luciferin. The stabilities of the reaction mixture as well as relevant ATP standards were quantified. The luminescent signals of the reaction mixture and a 0.5 µM ATP standard decreased linearly at rates of 2.16 and 1.39% decay/min, respectively. For a 25 µM ATP standard, the luminescent signal underwent a logarithmic decay, due to intrinsic deviations from the Beer-Lambert law. Moreover, to test the functionality of isolated mitochondria, they were incubated with 1 and 5 mM oligomycin, an inhibitor of oxidative phosphorylation. The rate of ATP production in the mitochondria declined by 34 and 83%, respectively. Due to the sensitivity and stability of the assay and methodology, we were able to quantitatively measure in vivo the effects of age and caloric restriction on the ATP content and production in isolated mitochondria from the brain and liver of young and old Fischer-344 rats. In both tissues, neither age nor caloric restriction had any significant effect on the ATP content or the rate of ATP production. This study introduces a highly sensitive, reproducible, and quick methodology for measuring ATP in isolated mitochondria.

DNA/RNA METHODOLOGY

Biological complexity emerges from different organizational levels in a highly regulated space-time coordi nation of processes that involves the participation and orchestrated interaction of DNA, RNA, and proteins between each other and the environment. Fully understanding normal biological processes such as cell differentiation, development and aging, and pathological conditions requires integrated genomic, transcriptional, and proteomic studies (1–3), which demand the simultaneous isolation of DNA, RNA, and proteins from the same sample.

Quick and reliable methods that perform simultaneous extraction of DNA, RNA, and proteins from a single sample are ideal for the generation of matched samples that can save time and money and allow for the efficient use of small and precious biological samples. Researchers are increasingly turning away from classic RNA and protein extraction techniques, such as phenol-chloroform separation (4) or time-consuming cesium chloride gradient centrifugation, because of the hazardous chemicals used and that the methods are generally unsuited for routine use in the laboratory. Spin column technology is a simple and quick approach to extracting nucleic acids from small biological samples. Furthermore, most column-based procedures do not require the amount of hazardous chemicals that are used in traditional nucleic acid extraction procedures (5).Recently, Morse and coworkers (5) discussed the combined extraction of RNA and proteins using RNA spin column–based technology, and Hummon et al. (6) showed an improved method for isolation and solubilization of proteins after TRIzol extraction of RNA and DNA from the same sample. However, none of these authors did a complete analysis of the proteins obtained at the level of two-dimensional (2-D) electrophoresis to compare the protein profile obtained with conventional methods used in proteomics studies. Here we present a methodology to simultaneously extract RNA/proteins and/or DNA, RNA, and proteins from the same sample using commercially available column-based nucleic acid extraction kits. We further compared the protein profile obtained with some of the methods dedicated to extracting proteins using 2-D electrophoresis, and we show that buffer choice is critical in the efficient extraction of proteins from these kits to allow proteomic studies.

6.Explain the Labotatory accreditation in detail.

Labotatory accreditation

Medical laboratory

A medical laboratory or clinical laboratory is a laboratory where tests are done on clinical specimens in order to get

information about the health of a patient as pertaining to the diagnosis, treatment, and prevention of diseases.

Departments

Laboratory medicine is generally divided into four sections, and each of which is further divided into a number of units. These

four sections are:

Anatomic Pathology: units are included here, namely histopathology, cytopathology, and electron microscopy.

Academically, each unit is studied alone in one course. Other courses pertaining to this section

include anatomy, physiology, histology, pathology, andpathophysiology.

Clinical Microbiology: This is the largest section in laboratory medicine; it encompasses five different sciences (units).

These includebacteriology, virology, parasitology, immunology, and mycology.

Clinical Biochemistry: Units under this busy section are instrumental

analysis, enzymology, toxicology and endocrinology.

Hematology: This small, yet busy, section consists of two units, which are coagulation and blood bank.

Genetics is also studied along with a subspecialty known as cytogenetics.

Distribution of clinical laboratories in health institutions varies greatly from one place to another. Take for example

microbiology, some health facilities have a single laboratory for microbiology, while others have a separate lab for each unit,

with nothing called a "microbiology" lab.

Laboratory equipment for hematology(black analyser) and urinalysis (left of the open centrifuge).

Here's a detailed breakdown of the responsibilities of each unit:

Microbiology receives almost any clinical specimen, including swabs, feces, urine, blood,sputum, cerebrospinal

fluid, synovial fluid, as well as possible infected tissue. The work here is mainly concerned with cultures, to look for

suspected pathogens which, if found, are further identified based on biochemical tests. Also, sensitivity testing is carried out

to determine whether the pathogen is sensitive or resistant to a suggested medicine. Results are reported with the identified

organism(s) and the type and amount of drug(s) that should be prescribed for the patient.

Parasitology is a microbiology unit that investigates parasites. The most frequently encountered specimen here

is faeces. However, blood, urine, sputum, and other samples may also contain parasites.

Virology is concerned with identification of viruses in specimens such as blood, urine, andcerebrospinal fluid.

Hematology works with whole blood to do full blood counts, and blood films as well as many other specialised tests.

Coagulation requires citrated blood samples to analyze blood clotting times and coagulation factors.

Clinical Biochemistry usually receives serum or plasma. They test the serum for chemicals present in blood. These

include a wide array of substances, such as lipids, blood sugar, enzymes, and hormones.

Toxicology mainly tests for pharmaceutical and recreational drugs. Urine and blood samples are submitted to this lab.

Immunology/Serology uses the concept of antigen-antibody interaction as a diagnostic tool. Compatibility of

transplanted organs is also determined.

Immunohaematology, or Blood bank determines blood groups, and performs compatibility testing on donor blood and

recipients. It also prepares blood components, derivatives, and products for transfusion. Regulated by the FDA since giving

blood is considered a drug, this unit determines a patient's blood type and Rh status, checks for antibodies to common

antigens found on red blood cells, and cross matches units that are negative for the antigen.

Urinalysis tests urine for many analytes. Some health care providers have a urinalysis laboratory, while others don't.

Instead, each component of the urinalysis is performed at the corresponding unit. If measuring urine chemicals is required,

the specimen is processed in the clinical biochemistry lab, but if cell studies are indicated, the specimen should be submitted

to the cytopathology lab, and so on.

Histopathology processes solid tissue removed from the body (biopsies) for evaluation at the microscopic level.

Cytopathology examines smears of cells from all over the body (such as from the cervix) for evidence of inflammation,

cancer, and other conditions.

Electron microscopy prepares specimens and takes micrographs of very fine details by means of TEM and SEM.

Genetics mainly performs DNA analysis.

Cytogenetics involves using blood and other cells to get a karyotype. This can be helpful in prenatal diagnosis

(e.g. Down's syndrome) as well as in cancer (some cancers have abnormal chromosomes).

Surgical pathology examines organs, limbs, tumors, fetuses, and other tissues biopsied in surgery such as breast

mastectomys.

Medical laboratory staff

Clinical laboratory in a Hospital setting with two technicians shown.

The following is the hierarchy of the clinical laboratory staff from highest authority to lowest:

Medical Director

Pathologist, Clinical biologist

Resident in Pathology, Anatomical pathology or Clinical biology

Pathologist Assistant,

Laboratory Manager,

Department Supervisor,

Chief/Lead Technologist,

Cytotechnologist, Medical Laboratory Scientist, Histotechnologist,

Medical Laboratory Technician, Histotechnician

Medical Laboratory Assistant (Lab Aide),

Phlebotomist,

Transcriptionist,

Specimen processor, Secretary).

Some of these titles don't exist in some countries. Sometimes technologists and technicians do the same work. In France, clinical

biologistsmay also be Medical director and laboratory manager.

Types of laboratory

In many countries, there are two main types of labs that process the majority of medical specimens. Hospital laboratories are

attached to ahospital, and perform tests on patients. Private (or community) laboratories receive samples from general

practitioners, insurance companies, and other health clinics for analysis. These can also be called reference laboratories where

more unusual and obscure tests are performed. For extremely specialised tests, samples may go to a research laboratory. A lot of

samples are sent between different labs for uncommon tests. It is more cost effective if a particular laboratory specializes in a rare

test, receiving specimens (and money) from other labs, while sending away tests it cannot do.

In many countries there are mainly three types of Medical Laboratories as per the types of investigations carried out. 1. Clinical

Pathology 2. Clinical Microbiology & 3. Clinical Biochemistry laboratories. 1. Clinical Pathology: Haematology,

Histopathology, Cytology, Routine Pathology2. Clinical Microbiology: Bacteriology, Mycobacteriology, Virology, Mycology,

Parasitology, Immunology, Serology.3. Clinical Biochemistry: Biochemical analysis, Hormonal assays etc.Blood Banks:- Blood

bank is a separate body. Its laboratory need Microbiological analysis for infectious diseases that may be found in blood.

Pathology to observe Blood grouping, Haematology & cross matching reactions. It also involves PRO department for the

communication & contact for blood donations etc..

Specimen processing and work flow

Sample processing will usually start with a set of samples and a request form.

Typically a set of vacutainer tubes containing blood, or any other specimen, will arrive to the laboratory in a small plastic bag,

along with the form.

The form and the specimens are given a laboratory number. The specimens will usually all receive the same number, often as a

sticker that can be placed on the tubes and form. This label has a barcode that can be scanned by automated analyzers and test

requests uploaded from the LIS. Entry of requests onto a laboratory management system involves typing, or scanning (where

barcodes are used) in the laboratory number, and entering the patient identification, as well as any tests requested. This allows

laboratory machines, computers and staff to know what tests are pending, and also gives a place (such as a hospital department,

doctor or other customer) for results to go.

For biochemistry samples, blood is usually centrifuged and serum is separated. If the serum needs to go on more than one

machine, it can be divided into separate tubes.

Many specimens end up in one or more sophisticated automated analysers, that process a fraction of the sample and return one or

more "results". Some laboratories use robotic sample handlers (Laboratory automation) to optimize the workflow and reduce

contamination risk and sample handling of the staff.

The work flow in a lab is usually heavy from 2:00 am to 10:00 am. Nurses and doctors generally have their patients tested at least

once a day with general complete blood counts and chemistry profiles. These orders are then drawn during a morning run

by phlebotomists for results to be available in the patient's charts for the attending physicians to consult during their morning

rounds. Another busy time for the lab is after 3:00 pm when private practice physician offices are closing. Couriers will pick up

specimens that have been drawn throughout the day and deliver them to the lab. Also, couriers will stop at outpatient drawing

centers and pick up specimens. These specimens will be processed in the evening and overnight to ensure results will be available

the following day.

Laboratory informatics

Laboratories today are held together by a system of software programs and computers that exchange data about patients, test

requests, and test results known as a Laboratory information system or LIS. The LIS is interfaced with the hospital information

system.

This system enables hospitals and labs to order the correct test requests for each patient, keep track of individual patient or

specimen histories, and help guarantee a better quality of results as well as printing hard copies of the results for patient charts

and doctors to check.

Result analysis, validation and interpretation

According to ISO 15189 norm, all pathological results must be verified by a competent professional. In some countries staff

like clinical scientists do the majority of this work inside the laboratory with abnormal results referred to the relevant pathologist.

In others, only medical staff (pathologist or clinical biologist) is concerned by this phase. It can be assisted by some software in

order to validate normal or non modified results. Medical staff are sometimes also required in order to explain pathology results

to physicians. For a simple result given by phone or for a technical problem it's a medical technologist explaining it to a

registered nurse.

Departments in some countries are exclusively directed by a specialized Pathologist, in others a consultant, medical or non-

medical, may be the Head of Department. Clinical Scientists have the right to interpret and discuss pathology results in their

discipline in many countries, in Europe they are qualified to at least Masters level, may have a PhD and can have an exit

qualification equivalent to medical staff e.g. FRCPath in the UK. In France only medical staff (Pharm.D. and M.D. specialized

in Anatomical pathology or Clinical biology) can discuss pathological results, clinical scientists are not considered as a part of

medical staff.

Scandal in the clinical lab industry

As medical technology advanced doctors were able to get more and more tests done in shorter and shorter amounts of time.

Where in the past a doctor might order a potassium and glucose and it would take hours for the results, now a doctor can order a

full chemistry panel of 20 or more different analytes and get the results in under an hour. The results are also much more accurate

and reliable now than in the past. Thus, into the 1970s and 1980s the lab became a source of profit within the hospital structure.

Some commercial labs began taking illegal and nefarious actions to increase their income. These practices included medicare and

medicaid fraud by performing and billing for tests that the ordering physician never ordered, paying kickbacks to private doctor

offices for sending their specimens to these reference labs, and other complicated criminal activity. These kickbacks

included donuts, free computers, fax machines, and more. These events culminated mostly in the mid-1990s with the SmithKline

Beecham Clinical Laboratory (SBCL) scandal.[2] It is believed SBCL paid at least $325 million in penalties and the industry as a

whole paid over $1 billion to insurance and government agencies that were defrauded. Ever since this time, the lab has become a

source of expense and loss in the hospital budget (commercial labs have nothing to do with hospitals) and lab medicine's

reputation was given a black eye. Now many labs have a compliance officer with mandatory annual meetings about compliance

for all employees.

Medical laboratory accreditation

Credibility of medical laboratories is paramount to the health and safety of the patients relying on the testing services provided by

these labs. The international standard in use today for the accreditation of medical laboratories is ISO 15189 - Medical

laboratories - particular requirements for quality and competence.

Accreditation is done by the Joint Commission, AABB, and other state and federal agencies. CLIA 88 or the Clinical Laboratory

Improvement Amendments also dictate testing and personnel.

The accrediting body in Australia is NATA, all laboratories must be NATA accredited to receive payment from Medicare.

In France, where accrediting body is COFRAC, in 2010, modification of legislation established ISO 15189 accreditation as an

obligation for all clinical laboratories.

UNIT-V

1.Explain the food laws and regulations in detail.

To meet a country’s sanitary and phytosanitary requirements, food must comply with the local laws and regulations to gain market access. These laws ensure the safety and suitability of food for consumers, in some countries; also govern food quality and composition standards.

The requirement of food regulation may be based on several factors such as whether a country adopts international norms developed by the Codex Alimentarius Commission of the Food and Agriculture Organization of the United Nations and the World Health Organization; good agricultural and manufacturing practices; or a country may also has its own suite of food regulations. Each country regulates food differently and has its own food regulatory framework. Usually more than one agency is involved in food regulations e.g. health and agriculture, they may have centralized or regionally controlled food regulations, and different agencies may be involved in enforcement activities.

 

Types of food safety and quality standards that apply in most countries:

 Food Safety and Standards Act

The Indian Parliament has recently passed the Food Safety and Standards Act, 2006that overrides all other food related laws. It will specifically repeal eight laws:

The Prevention of Food Adulteration Act, 1954 The Fruit Products Order, 1955 The Meat Food Products Order, 1973 The Vegetable Oil Products (Control) Order, 1947 The Edible Oils Packaging (Regulation) Order, 1998 The Solvent Extracted Oil, De oiled Meal, and Edible Flour (Control) Order, 1967 The Milk and Milk Products Order, 1992 Essential Commodities Act, 1955 relating to food

 The Act establishes a new national regulatory body, the Food Safety and Standards Authority of India, to develop science based standards for food and to regulate and monitor the manufacture, processing, storage, distribution, sale and import of food so as to ensure the availability of safe and wholesome food for human consumption. All food imports will therefore be subject to the provisions of the Act and any rules and regulations made under the Act.

As a temporary measure, the standards, safety requirements and other provisions of the repealed Acts and Orders and any rules and regulations made under them will continue to be in force until new rules and regulations are put in place under the  Food Safety and Standards Act, 2006. For that reason, importers will for some time have to continue to take into account the provisions of those repealed Acts and Orders.

 

Prevention of Food Adulteration Act

A basic statute (Prevention of Food Adulteration Act (PFA) of 1954 and the PFA Rules of 1955, as amended) protects India against impure, unsafe, and fraudulently labelled foods. The PFA standards and regulations apply equally to domestic and imported products and cover various aspects of food processing and distribution. These include food colour, preservatives, pesticide residues, packaging and labelling, and regulation of sales. Further details are available from the Ministry of Health and Family Welfare. All imported products must adhere to the rules specified in the Act and its regulations, including those covering labelling and marketing requirements. The PFA focuses primarily on the establishment of regulatory standards for primary food products, which constitute the bulk of the Indian diet.

 PFA rules sometimes appear to be drafted in a manner that goes beyond the mere establishment of minimum product quality specifications, by prescribing recipes for how food products are to be manufactured.

There is an appeals process for amending rules, although this is time-consuming. The Central Committee for Food Standards, chaired by the Director General of Health Services, is the decision-making entity Syrups.

 

Weights and measures

Standards for weights and measures are administered by the Ministry of Consumer Affairs, Food and Public Distribution under the Standards of Weights and Measures Act, 1976 and related rules and notifications. All weights or measures must be recorded in metric units and certain commodities can only be packed in specified quantities (weight, measure or number). These include baby and weaning food, biscuits, bread, butter, coffee, tea, vegetable oils, milk powder, and wheat and rice flour.

Shelf life

At the time of importation food products are required to have a valid shelf life, or residual shelf life, of not less than 60 per cent of their original shelf life. For more information, see the relevant notification at the Government of India Ministry of Commerce and Industry website.

 

Fruit Products Order

The fruit and vegetable processing sector is regulated by the Fruit Products Order, (FPO), which is administered by the Department of Food Processing Industries.

The FPO contains specifications and quality control requirements regarding the production and marketing of processed fruits and vegetables, sweetened aerated water, vinegar, and synthetic syrups.

All such processing units are required to obtain a license under the FPO, and periodic inspections are carried out. Processed fruit and vegetable products imported into the country must meet the FPO standards.

 

Meat Food Products Order

Regulations for the production of meat products are covered by the Meat Food Products Order, .

The Order:

Specifies sanitation and hygiene requirements for slaughterhouses and manufacturers of meat products. Contains packing, marking and labeling provisions for containers of meat products. Defines the permissible quantity of heavy metals, preservatives, and insecticide residues in meat products.

The Directorate of Marketing and Inspection at the Ministry of Agriculture is the regulatory authority for the order, which is equally applicable to domestic processors and importers of meat products.

 

 Livestock Importation Act

India has established procedures for the importation of livestock and associated products under the Livestock Importation Act, 1898.

Under the regulations, the import of meat products, eggs and egg powder and milk products require a sanitary import permit from the Department of Animal Husbandry, Dairying and Fisheries at the Ministry of Agriculture.

A detailed import risk analysis is carried out, taking into account the disease situation prevailing in the exporting country compared with the disease situation in India.

 

Milk and Milk Products Order

The production, distribution and supply of milk products is controlled by the Milk and Milk Products Order, 1992. The order sets sanitary requirements for dairies, machinery, and premises, and includes quality control, certification, packing, marking and labeling standards for milk and milk products.

Standards specified in the order also apply to imported products. The Department of Animal Husbandry, Dairying and Fisheries at the Ministry of Agriculture is the regulatory authority.

 

Essential Commodities Act, 1955: The main objective of the Act is to regulate the manufacture, commerce, and distribution of essential commodities, including food. A number of Control Orders have been promulgated under the provisions of this Act. These are:

 

Standards of Weights and Measures Act, 1976 and the Standards of Weights and Measures (Packaged Commodities) Rules, 1977: The Act governs sale of packaged commodities and provides for mandatory registration of all packaged products in the country.

 

Consumer Protection Act, 1986: The Act provides for constitution of District Forum/State/National Commission for settlement of disputes between the seller/service provider and the consumer.

The Infant Milk Substitutes, Feeding Bottles and Infant Foods (Regulation of Production, Supply and Distribution) Act, 1992 and Rules 1993: This Act aims at promoting breast feeding and ensuring proper use of infant milk substitutes and infant food.

The Insecticide Act, 1968: The Act envisages safe use of insecticides so as to ensure that the leftover chemical residues do not pose any health hazard.

Export (Quality Control and Inspection) Act, 1963: The Act aims at facilitating export trade through quality control and inspection before the products are sold to international buyers.

Environment Protection Act, 1986: This Act incorporates rules for the manufacture, use, import and storage of hazardous microorganisms / substances / cells used as foodstuff.

Pollution Control (Ministry of Environment and Forests): A no-objection certificate from the respective State Pollution Control Board is essential for all dairy plants.

(i) Industrial Licences: No licence is required for setting up a dairy plant in India. Only a memorandum has to be submitted to the Secretariat for Industrial Approvals (SIA) and an acknowledgement obtained. However, a certificate of registration is required under the Milk and Milk Products Order (MMPO), 1992.

 

Voluntary Standards

There are two organizations that deal with voluntary standardization and certification systems in the food sector. The Bureau of Indian Standards looks after standardization of processed foods and standardization of raw agricultural produce is under the purview of the Directorate of Marketing and Inspection.

 

Bureau of Indian Standards (BIS)

The activities of BIS are two fold the formulation of Indian standards in the processed foods sector and the implementation of standards through promotion and through voluntary and third party certification systems. BIS has on record, standards for most of processed foods. In general, these standards cover raw materials permitted and their quality parameters; hygienic conditions under which products are manufactured and packaging and labelling requirements. Manufacturers complying with standards laid down by the BIS can obtain and "ISI" mark that can be exhibited on product packages. BIS has identified certain items like food colours/additives, vanaspati, and containers for packing, milk powder and condensed milk, for compulsory certification.

 

Directorate of Marketing and Inspection (DMI)

The DMI enforces the Agricultural Products (Grading and Marketing) Act, 1937. Under this Act, Grade Standards are prescribed for agricultural and allied commodities. These are known as "Agmark" Standards. Grading under the provisions of this Act is voluntary. Manufacturers who comply with standard laid down by DMI are allowed to use "Agmark" labels on their products.

 

Management Systems for Quality and Food Safety

ISO 9000 Quality Management Systems

The ISO 9000 system is looked at as a system with minimum quality requirements. It builds a baseline system for managing quality. The focus, therefore, is on designing a total quality management system, one that complies with external standards, but includes the specific requirement of industry and integrates elements of competitiveness.The millennium standard (ISO

9000:2000) has changed the focus from procedure to process. The main features of the ISO 9000:2000 standards are:

 

Refinement in the presentation to make reading easy and elimination of general inauditable statements such as "consideration shall be given”

The present standard gave an impression that it was applicable to manufacturing situation though it was applied in organizations of different types and sizes, including the service sector. The new standard is a broad-based standard applicable to all sectors.

In the new standards, approach has changed from continuous improvement to continual improvement. Continuous improvement remained an implied approach to quality improvement in ISO 9000.

 

Plant Quarantine Order

India introduced the Plant Quarantine (Regulation of Import into India) Order in 2003 to prohibit and regulate the import of agricultural articles. Orders include:

A ban on the import of certain plants and planting materials from designated countries (eg sugarcane from Australia)

A restriction on the import of other plants and plant materials to authorized institutions, with additional declarations and special conditions attached.

A requirement for additional declarations (such as a phytosanitary certificate issued by the exporting country) and special conditions for a further positive list of plants and plant materials. The Order, with amendments, is available at the Department of Agriculture and Cooperation and Plant Quarantine Organization of India websites. The implementing agency is the Directorate of Plant Protection, Quarantine, and Storage, under the Department of Agriculture and Cooperation, Ministry of Agriculture.

 

Export (Quality Control and Inspection) Act, 1963

The Export Inspection Council is responsible for the operation of this Act. Under the Act, a large number of exportable commodities have been notified for compulsory pre-shipment inspection. The quality control and inspection of various export products is administered through a network of more than fifty offices located around major production centres and ports of shipment. In addition, organizations may be recognized as agencies for inspection and /or quality control. Recently, the government has exempted agriculture and food products, fruit products and fish and fishery products from compulsory pre-shipment inspections; provided that the exporter has a firm letter from the overseas buyer stating that the overseas buyer does not require pre-shipment inspection from official Indian inspection agencies.

 

Other Government Regulations

Industrial Licence:

No licence is required for setting up a Dairy Project in India. Only a Memorandum has to be submitted to the Secretariat for Industrial Approvals (SIA) and an acknowledgment is to be obtained.

However Certificate of Registration is required under the Milk and Milk Products Control Order (MMPO) 1992.

 

Foreign Investment:

Foreign Investment in dairying requires prior approval from the Secretariat of Industrial Approvals, Ministry of Industry, as dairying has not been included in the list of High Priority Industries.

Automatic approval will be given upto 51% Foreign Investment in High Priority Industries.

In case of other Industries, proposals will be cleared on case to case basis. Government may allow 51% without enforcing the old limit of 40% applicable under Foreign Exchange Regulations Act at its discretion.

 

Foreign Technology Agreements:

Foreign Technology Agreements are freely allowed in high priority industries under the following terms:Lump sum payment of Rs 10 million

Royalty payment of 5% on domestic sales and 8% as exports subject to total payment of 8% on sales turnover, over a 10 year period from the date of agreement or 7 years from commencement of production.

Foreign Technology Agreements in dairying also need prior approval. Foreign Exchange required for payment of Royalty will have to be purchased at market rates.

Foreign Technicians can be freely hired.

 

Import of Capital Goods

Import of capital goods is automatically allowed if it is financed through Foreign Equity. Alternatively, approval is needed from the Secretariat of Industrial Approvals. The approval depends on the availability of Foreign Exchange Resources.

 

Import of Second Hand Capital Goods

Import of Second hand goods is allowed subject to the following conditions:

Minimum Residual life of 5 years

The equipment should not be more than 7 years old

A certificate from the Chartered Engineers of the country of origin certifying the age and the Residual life is to be produced.

Import will be allowed only for actual users.

 

Dividend Balancing

Remittances of dividend should be covered by earnings from exports recorded in the years prior to the payment of dividend or in the years of the payment of the dividend.

 2.Explain the Prevention of Food Adulteration Programme

2.Prevention of Food Adulteration Programme in detail.

The Ministry of Health and Family Welfare is responsible for ensuring safe food to the consumers. Keeping this in view, a legislation called "Prevention of Food Adulteration Act, 1954" was enacted. The objective envisaged in this legislation was to ensure pure and wholesome food to the consumers and also to prevent fraud or deception. The Act has been amended thrice in 1964, 1976 and in 1986 with the objective of plugging the loopholes and making the punishments more stringent and empowering Consumers and Voluntary Organisations to play a more effective role in its implementation.

The subject of the Prevention of Food Adulteration is in the concurrent list of the constitution. However, in general, the enforcement of the Act is done by the State/U.T Governments. The Central Government primarily plays an advisory role in its implementation besides carrying out various statutory functions/duties assigned to it under the various provisions of the Act.

The laws regulating the quality of food have been in force in the country since 1899. Until 1954, several States formulated their own food laws. But there was a considerable variance in the rules and specifications of the food, which interfered with inter-provincial trade. The Central Advisory Board appointed by the Government of India in 1937 and the Food Adulteration Committee appointed in 1943, reviewed the subject of Food Adulteration and recommended for Central legislation. The Constitution of India provided the powers to Central Government for making such legislation as the subjects of Food and Drugs Adulteration are included in the concurrent list. The Government of India, therefore, enacted a Central Legislation called the Prevention of Food adulteration Act (PFA) in the year 1954 which came into effect from 15 June, 1955. The Act repealed all laws, existing at that time in States concerning food adulteration.

In India, a three-tier system is in vogue for ensuring food quality and food safety. They are:

Government of India; State/UT Governments;

Local Bodies.

The Prevention of Food Adulteration Act is a Central legislation. Rules and Standards framed under the Act are uniformly applicable throughout the country. Besides, framing of rules and standards, the following activities are undertaken by the Ministry of Health and Family Welfare.

Keeping close liaison with State/local bodies for uniform implementation of food laws. Monitoring of activities of the States by collecting periodical reports on working of food laws, getting the reports of

food poisoning cases and visiting the States from time to time.

Arranging periodical training programme for Senior Officer/Inspector/Analysts.

Creating consumer awareness about the programme by holding exhibitions/seminars/training programmes and publishing pamphlet'.

Approving labels of Infant Milk Substitute and Infant food, so as to safeguard the health of infants.

Coordinating with international bodies like ISO/FAO/WHO and Codex.

Carrying out survey-cum-monitoring activities on food contaminants like colours.

Giving administrative/financial/technical support to four Central Food Laboratories situated in Kolkata, Ghaziabad, Mysore and Pune and providing technical guidance to the food laboratories set up by the States/Local Bodies.

Holding activities connected with National Monitoring Agency vested with powers to decide policy issues on food irradiation.

Formulation of Manual on food analysis method.

The Ministry of Health and Family Welfare is designated as the National Codex Contact Point in India to examine and formulate India's views on the agenda for the various meeting of Codex Alimentarius Commission, a joint venture of FAO/WHO dealing with International Food Standards and its subsidiary committees. The Ministry of Health and Family Welfare constituted a National Codex Committee (NCC) and an Assistant Director General (PFA) has been working as Liaison Officer for NCC. The NCC has further constituted 24 Shadow Committees corresponding to various Codex commodities committees for preparation and finalization of India's stand.

India has been regularly atending the various sessions of the Codex Alimentarius Commission and various Codex Commodity Committees to put forward her views and defend these views.

Harmonisation of PFA with Codex

After signing the Sanitary and Phytosanitary (SPS) and Technical Barrier to Trade (TBT) agreements by India and removal of quantitative restrictions on import of food products into India, the exercise of harmonization of standards for food products, use of food additives, microbiological requirements, harmonization of regulations, in line with international standards prescribed by Codex Alimentarius Commission and International Standards Organisation (ISO) had been initiated.

Prevention of Food Adulteration ProgrammeRole of State/UT Governments

Enforcement of the food laws primarily rests with the State/UTs. There are 28 States and 7 Union Territories in the country. The implementation of the Act in most of the States is under the administrative control of the Directorate of Health Services, whereas, in a few States, the implementation is being combined with Drugs Administration under the Joint Food and Drug Administration. The implementation has been left to the administrative setup of the States, but it has been stressed on the States that whatever the structure be, there should be a whole-time Senior Officer duly qualified and experienced in Food Science, Food Technology, Food Analysis with other supporting officers and inspectors. State Governments are also empowered to make rules laying down details of licensing conditions of food, the establishments of food industries and prescribing licence fees.

The provisions under PFA Rules have been amended nearly 360 times and standards of around 250 articles of food which are of mass consumption have been prescribed. While making amendments, standards formulated by Codex/technological development in the food industry sector/dietary habits/nutritional status of our population, social/cultural practices are taken into consideration.

By and large, in most of the States, implementation in corporation/municipal area rests with the Local Bodies which employ their own food inspectors. Licensing of food industries/establishments is also left to them.

There are 72 food laboratories in the country at District/Regional or State level in addition to four Central Food Laboratories set-up by the Central Government. Almost every State has got one or more laboratory depending upon its need. About 12 of these laboratories are under the administrative control of the local bodies whereas the remaining ones are under the administrative control of the State Government.

Following constraints have been noticed in the programme:

Shortage of Food Inspectors with the States/Local Bodies, Deficiency in the testing laboratories on the following counts:

Inadequate trained manpower,

Inadequate testing facilities,

Non-availability of sophisticated equipment,

Inadequate budgetary provision,

Non-availability of reference standard material,

Non-availability of programme officer for PFA with the State/Local Bodies at State and District levels,

Non-availability of separate legal cell for trial of PFA cases with the State/Local Bodies,

Non-availability of regular refresher training programme for all the functionaries.

Efforts of Central Government for Solving the Constraints

Refresher training programmes are being arranged for all the functionaries namely: (a) Food Inspectors, (b) Local (Health) Authorities, (c) Food (Health) Authorities, (d) Public Analyst and Chemist. Training for Analysts and Chemists are being organized in their own laboratories by trainer deputed by the Central Government. These trainers stay in one lab for six working days and first of all they setup the laboratory as per Good Laboratory Practices and thereafter, the specific training is organized.

Sophisticated equipments are being supplied to State Food Testing Laboratories so that at least one laboratory in each State is appropriately strengthened. Efforts are being made to ensure that warranty of the equipment so supplied are for minimum 3 years along with consumables and proper trainings is provided to the analysts/chemists by the supplier for handling and running the equipment.

Efforts are also being made to ensure that each State is linked electronically with its District Headquarters. The expenditure for this is proposed to be provided from the World Bank Assisted Capacity Building Project for food and drugs being implemented by the Central Government. This will facilitate smooth sharing of information and networking.

Efforts are being made to provide at least one analyst from the Central Budget through the World Bank Assisted Project in each Food Testing Lab for a period of 5 years.

Standard reference material for pesticides, listed under Rule 65 of PFA Rules, all the metals listed under Rule 57 of the PFA Rules and aflatoxin are being supplied to one lab in each State.

Books on methods of analysis like AOAC, Pearson, Food Chemical Codex, have already been supplied to a majority of the laboratories.

Training programme for consumers, traders, vendors and street food hawkers have been organized and will be organized in future as a consumer education programme on food safety.

Sensitisation training programmes have been organized for Port (Health) Officers/Customs Officers/Customs House Clearing Agents and importers on various provisions of PFA Act/Rules and other provisions namely packaged Commodity Order and Customs Act, so that these officers may appropriately handle the imported food product.

The Food Safety and Standards Act, 2006: With the coming into effect of the Food Safety and Standards Act, 2006 (FSSA) enacted by Parliament in August 2006, the Prevention of Food Adulteration Act, 1954 stands repealed from the date on which Food Safety and Standards Act comes into force on such date as the Central Government may, by notification in the Gazette.

Notwithstanding the repeal of the enactment and Orders specified in the Second Schedule, the standards, safety requirements and other provisions of the Act and the rules and regulations made there under and Orders listed in that Schedule shall continue to be in force and operate till new standards are specified under this Act or rules and regulations made there under.

Provided that anything done or any action taken under the enactment and Orders under repeal shall be deemed to have been done or taken under the corresponding provisions of this Act and shall continue in force accordingly unless and until superseded by anything done or by any action taken under this Act.

World Bank Assisted-Capacity Building Project on Food Safety

As trade in food commodities expands globally, food safety can no longer be considered a mere domestic issue. The agreements under the WTO require the development of modern food control and safety programs by national Governments. The issue does not relate only to end product parameters but also to process control.

In order to strengthen the food safety infrastructure in the country, a 5 year World Bank Aided Capacity Building Project for Food Safety and Quality Control of Drugs has been launched by the Central Government.

The Project Objectives/Components are as below:

To enhance the capacities of laboratories at the State and Central levels through infrastructure strengthening and training of personnel to upgrade their existing skills. It is separately proposed that only those labs be allowed to do statutory testing which are accredited to NABL (National Accrediation Board for Testing and Calibration Laboratories).

To introduce GMP (Good Manufcturing Practice) and HACCP (Hazard Analysis and Critical Control Points) in the medium and small-scale food processing operations and upgrade facilities in the laboratories including testing for microbiological contamination.

To create greater awareness of food safety and hygiene in the small, cottage and unorganised sectors including the street food sector through training,

To develop a system of continuous surveys of households to get client perceptions which will provide substantive inputs for policy development and program improvements.

Setting up of Management Information System and electronic linkages between Central and State Offices and Central and State Labs in the area of food to ensure better monitoring and data collection.

FRUIT PRODUCTS ORDER (FPO), 1955Fruit Products Order - 1955, promulgated under section 3 of the Essential Commodities Act — 1955, aims at regulating sanitary and hygienic conditions in manufacture of fruit, vegetable products. It is mandatory for all manufacturers of fruit & vegetable products to obtain license under this Order to ensure good quality products, manufactured under hygienic conditions. The Fruit Product Order lays down tie minimum requirements for:

1. Sanitary and hygienic conditions of premises, surroundings and personnel.

2. Water to be used for processing.

3. Machinery and equipment.

4. Product standards.

Besides this, maximum limits of preservatives, additives and contaminants have also been specified for various products.

This order is implemented by Department of Food Processing Industries through the Directorate of Fruit & Vegetable Preservation at New Delhi. The Directorate bas four regional offices located at Delhi, Mumbai, Calcutta and Chennai, as well as sub-offices at Lucknow and Guwahati. The officials of the Directorate undertake frequent inspections of the manufacturing units and draw random

samples of products from the manufacturers and markets which are analyzed in the laboratories to test their conformity with the specifications laid under FPO.

The Central Fruit Products Advisory Committee comprising of the officials of concerned Government Departments, technical experts, representatives of Central Food Technology Research Institute, Bureau of Indian Standards, Fruit and vegetable Producers and Processing Industry, is responsible for recommending amendments in the Fruit Product Order. In view of the demands of the industry,-and the liberalized economic scenario, major amendments were made in FPO during 1997. It bas been amended further in the year 2000 in consumer interest.

CODEX ALIMENTARIUS COMMISSIONCodex Alimentarius Commission is an International Commission constituted by Food and Agriculture Organization (FAO) and World Healtb Organisation (WHO) of United Nations whose objective is to protect the health of consumers and to ensure fair practices in tine food trade. The term Codex Alimentarius" is taken from Latin Language and means food code'. The Codex Alimentarius is a collection of International Standards for the safety and quality of food as well as codes of good manufacturing practice and other guidelines to protect the health of consumers and remove unfair practices in International Trade. These standards, guidelines and recommendations are recognized worldwide for international trade negotiations and also for settlings of disputes by WTO.