Food safety

By Dr Utpal Sharma

Assistant ProfessorDepartment of Community Medicine

SMIMS, Gangtok, Sikkim

Introduction Food is the most important item to sustain life on this

planet, next only to oxygen

However it is a potent source of pathogens, toxins and disease.

Food is liable to contamination, at any point during its journey from the producer to the consumer.

Human consumes 30 tons of food during his lifetime….????

What is food hygiene….?????

Food hygiene, in its widest sense, implies hygiene in the production, handling, distribution and serving of all types of food.

The primary aim of food hygiene is to prevent food poisoning and other food-borne illnesses.

The importance of surveillance of food-borne diseases has been underlined in the WHO Sixth General Program of Work .

The most important international program carrying out activities in the field of food hygiene is the Joint FAO/WHO food Standards Program

Food hygiene is more than cleanliness .....

1. Protecting food from risk of contamination, including harmful bacteria, poison and other foreign bodies.

2. Preventing any bacteria present multiplying to an extent which would result in the illness of consumers or the early spoilage of the food.

3. Destroying any harmful bacteria in the food by thorough cooking or processing.

4. Discarding unfit or contaminated food.

What if food hygiene compromised…???

1. Food poisoning outbreaks and sometimes death2. Food contamination, customer complaints and brand image3. Pest infestations 4. Waste food due to spoilage5. The closure of food premises6. Fines and costs of legal action taken because of

contraventions in hygiene legislation, or because of the sale of unfit or unsatisfactory food.

7. Civil action taken by food poisoning suffers8. Loss of production and food which has to be destroyed 9. Decontamination cleaning and replacement of damaged

equipment.

Classification of Food – borne Illnesses Bacterial diseases (infections & intoxications)

Typoid fever, paratyphoid fever, Salmonellosis, Staphyloccal intoxication, Cl. perfringens illness Botulismb. cereus Food Poisoninge. coli diarrhoeanon-cholera vibrio illnessV. parahaemolyticus - infection, streptococcal infection, Shigellosis, Brucellosis

Viral diseases Viral hepatitis, Gastroenteritis

Parasites Taeniasis, Hydatidosis, Trichinosis, Ascariasis, Amoebiasis, Oxyuriasis

Classification of Food – borne Illnesses

Chemical poisons Pesticides, heavy metals (arsenic, lead, cadmium, etc.)

Food toxins Lathyrism, Epidemic dropsy, Aflatoxins , Endemic ascities, Fusarium toxins

Food borne pathogen and associated diseases

Milk hygieneMilk is an efficient vehicle for a great variety of

disease agents. The sources of infection or contamination of milk

may be The dairy animal Human handler or The environment, e.g., contaminated vessels, polluted

water, flies, dust, etc.The milk hygiene begins at its source of production

namely the dairy farm.

Diseases conveyed through milkDisease Organism Reservoir/SourceTuberculosis M tuberculosis (bovine) Cattle

Brucellosis B abortus / melitensis Cattle, Goat

Q Fever Coxiella burnetti Cattle

Septic Sore throat Streptococcus pyogenes Cattle, milk handlers

Food Poisoning Staphylococcus aureus Cattle, milk handlers

Diarrhoea and dysenteries

Shigella, E histolytica Milk handlers

Cholera Vibrio cholerae Water, milk

Enteric fever Salmonella species Milk

Viral hepatitis, polio Hepatitis A,

Polio viruses Milk

Diphtheria Corynebacterium diphtheriae

Milk

Clean and safe milk The safety and keeping quality of milk are related to its

microbial content.

The first is a healthy and clean animal.

Milk from a healthy udder contains only a few organisms, and these are relatively unimportant.

Secondly, the premises where the animal is housed and milked should be sanitary.

The milk vessels must be sterile and kept covered. The water supply must be bacteriologicaly safe.

Cont…

Milk handler must be free from communicable diseases, and before milking they must wash their hands and arms.

Where possible, milking machines must be used.

A periodical medical examination of personnel and the all other logistic is recommended.

Milk should be cooled immediately to below 10°C after it is drawn to retard bacterial growth.

In the production of good quality milk, cleanliness of all containers and equipment in which milk is handled is very important.

What kind of milk is acceptable…???

Milk only without the microbial contamination is acceptable of consumption purpose.

Methylene blue testThis is done in order to detect microorganisms in milkThe test is carried out in the milk accepted for

pasteurizationBased on the fact that there is a decrease in colour

imparted to the milk if it is contaminated with bacteria.

Methylene blue test…

The sample of milk retaining blue color for the longest duration us considered to be of best quality

It is because the sample requiring shortest time will be having more microorganisms to reduce methylene blue

Inference

Pasteurization of milk Boiling kills the microorganisms but affects the quality,

taste and flavour of milk, as constituents are heat-labile Pasteurization involves rapidly heating milk (< the boiling

point), maintaining it uniformly over a definite period and rapidly cooling it.

This destroys most and of the pathogenic microorganisms, reduces the total quantity of all the microorganisms without affecting its inherent qualities (taste and flavour)

It may not sterilize milk but makes it non-infective, retains its nutritive and aesthetic qualities and improves its keeping quality.

Milk is kept at 63-66°C for at least 30 minutes, and then quickly cooled to 5°C.

The low temperature must be

maintained till the milk is c

onsumed.

Methods of PasteurizationHolder (Vat) method : Milk is heated to the temperatures between 63ºC and 65.5º C Held in large tanks at that temperature for 30 min rapidly cooled to 5°C.

High Temperature Short Time (HTST) Method Milk is heated to 72°C Helt at same temperature for15 seconds and then rapidly cooled

to 4ºC.

Utra High Temperature Method (UHT Method) Milk is rapidly heated usually in 2 stages (the second stage

usually being under pressure) to between 125°C, for a few seconds only.

It is then rapidly cooled and bottled as quickly as possible.

Hygienically produced pasteurize milk has a

keeping quality of not more than 8-12 hours

a t 18°C

Tests of pasteurized milkPhosphatase Test : Based on the fact that the enzyme phosphatase is destroyed by the

pasteurization temperatures; but not at a lower temperature The test is performed by addition of disodium phenyl-phosphate to

pasteurized milk. The enzyme phosphatase, if present, splits up the giving different shades of

blue colour depending upon the amount enzyme present. The colour is matched against the standard colours in a Lovibond

colorimeter. (Standard is < 2.3 Lovibond units)

Standard plate count A limit of 30,000bacterial count per ml is the standard in most of the

countries

Coliform count Absence of coliform in 1 ml of milk is accepted as properly pasteurized milk

Food jargons…..!!!Food Processing Food processing is the technique used to transform raw

ingredients into food or to transform food into other forms for consumption e.g baking steaming etc.

Food Additives Non-nutritious substances added intentionally to food, generally

in small quantity, to improve the basic properties of food like its appearance, flavour, texture e.g colouring agents

Food Fortification Food Fortification is the whereby nutrients are added to foods

in relatively small quantities to maintain or improve the quality of diet of a group, a community, or a population e.g iodized salt

Food toxicantsNeurolathyrism

A neurodegenerative disease that is

caused by heavy consumption of grass pea, Lathyrus sativus.

Active neurotoxin is called -oxalyl amino alanine (BOAA)

Upper motor neuron disorder with symmetrical spastic paralysis.

Sensation and sphincters are spared.

Cont…. Most commonly seen in men in the age group 15-45 years Onset is sudden, often preceded by exertion or exposure to cold. A patient may find himself paralyzed on getting up in the morning. Sometimes backache and stiffness of legs precede the paralysis

of legs. The patient may pass through progressive stages of severity

Latent stage No-stick stage On-stick stage Two-stick stage Crawler stage

Interventions

Vit C prophylaxis Steeping

Banning the crop Education

Parboiling

Genetic approach

Cont…..

Aflatoxin The first known outbreak of Aflatoxicosis probably occurred in England in

1960, among young turkeys fed on infested groundnut.

Causative Agent : Aspergillus flavus and Aspergillus parasiticus affects foods in poor storage conditions of high temperature (30-37°C),high

humidity, as is common in the rainy season and during floods and cyclones. The fungus Infests improperly stored foods like maize, groundnut, soya,

sorghum, rice, wheat, sunflower, tree nuts, spices and even milk and cheese.

Toxins : Aflatoxin B1 is the most potent known natural hepatocarcinogen. They are known to cause hepatitis (jaundice), ascitis, portal hypertension, liver cirrhosis and hepatocellular carcinoma.

Cont…..

Ergot (Claviceps fusiformis &Claviceps purpurae) It is a field fungus Infests foodgrains like bajra, sorghum and wheat during the

flowering stage. fungus grows as a blackish mass and imparts black colour to the

seed Symptoms are acute but rarely fatal Includes nausea, vomiting, abdominal cramps and drowsiness

for 24-48 hours after ingestion In chronic cases painful cramps in limbs along with peripheral

gangrene due to vasoconstriction could be seen (St. Anthony’s fire in France in the 11th century)

Prevention Infested grains can be easily removed by floating them

in 20% salt water Upper limit is 0.05 mg per 100 gm of food material

Cont….

Epidemic dropsy The active agent is sanguinarine, and the cause is

contamination of mustard oil with argemone oil. Symptoms included

Sudden non-inflammatory, bilateral swelling of the legs associated with diarrhoea

In advanced stage patient gets dyspnoea and signs of congestive cardiac failure (CCF)

If not treated death may ensue, mortality rate of 5-50% has been reported.

Tests to detect argemone oil contamination Nitric acid test ( positive when argemone oil is 0.25%) Paper chramatography (Detect upto a concentration of 0.0001%)

Prevention Removing the weeds of argemone after harvest Strict enforcement of PFA

Cont….

Endemic ascitis Causitive agent is hepatotoxin pyrrolizidine alkaloid found in

Crotalaria (jhunjhunia) seeds

Symptoms comprises of ascities and jaundice

Both sexes in all age group, except infants are affected

Overall mortality is about 40%.

Prevention Educating people Deweeding jhunjhunia plants Sieving of millets at household level.

Cont…

Fusarium toxins It is another field fungus affecting crops like sorghum, rice and

maize. seen in the subtropical and temperate regions. The fungus produces toxins like deoxynivalenol and fumonisin Symptoms includes vomiting and diarrhoea.

Detection of Mycotoxins : Many sophisticated methods are available for the detection of

Mycotoxins. Thin Layer Chromatography (TLC), Radio-immuno Assay (RIA) and ELISA tests are available.

Thank you folks ….be

safe