1Biochemical principles of nutrition

Nutrition may be defined as the science of food and its relationship to health. It is concerned primarily with the part played by nutrients in body growth, development and maintenance. The word nutrient or "food factor" is used for specific dietary constituents such as proteins, vitamins and minerals. Dietetics is the practical application of the principles of nutrition; it includes the planning of meals for the well and the sick. Good nutrition means "maintaining a nutritional status that enables us to grow well and enjoy good health".

In various historical times structure of nutrition and character of a nutrition changed depending on development of industrial forces of a society,climate-geographical conditions, direction of economic activity and so on. The character of nutrition of the population was formed gradually depending on an economic and cultural level of development of the country, in view of national customs and features.Through centuries, food has been recognized as important for human beings in health and disease.

Good nutrition is a basic component of health. The relation of nutrition to health may be seen from the following view points: Growth and development: Good nutrition is essential for the attainment of normal growth and development. Not only physical growth and development, but also the intellectual development, learning and behaviour are affected by malnutrition. Specific deficiency: Malnutrition is directly responsible for certain specific nutritional deficiency diseases. Good nutrition therefore is essential for the prevention of specific nutritional deficiency diseases and promotion of health. Resistance to infection: Infection, in turn, may aggravate malnutrition by affecting the food intake, absorption and metabolism.Mortality and morbidity: The indirect effects of malnutrition on the community are even more striking - a high general death rate, high infant mortality rate, high sickness rate and a lower Expectation of life.

'You are what you eat', some people say. If you eat rubbishy food, you can't really expect to grow up strong and healthy. But if you eat good-quality food, you've a good chance of doing so. That's just commonsense really.

Main rules of healthy nutritionalEating fruits, vegetables, and grain products that contain fiber may help prevent heart disease

Limiting the amount of saturated fat and cholesterol in your diet may reduce your risk of heart disease

Limiting the amount of total fat you eat may help reduce your risk for cancer

Eating fiber-containing grain products, fruits, and vegetables may help prevent cancer

Eating fruits and vegetables that are "low in fat" and "good sources" of dietary fiber, vitamin A, or vitamin C may help prevent cancer

Nutrition as a science can be regarded as the study of six main categories of food components protein vitaminsfatwater carbohydrate minerals

WaterWater is necessary to make up the loss caused by its excretion in breath, sweat, urine, faces, and also to renew all the various fluids and solid organs of the body.It is estimated that about 2 liters of water enters the body daily as such or as a part of cooked food, beverages etc. Out of which 1.37 - 1.81 liters is excreted daily in urine, sweat etc.Some important uses of water are:- As a solvent for transportation of nutrients in the body.- It helps regulating body temperature through evaporation from lungs and skin.- As an aid in removing wastes of metabolism in the urine.- As an aid in functions like osmosis.

Diseases, that is direct or mediate related with a nutrition 1. Alimentary disease, illness caused by deficiency or surplus of components of nutrition. 4. Disease, which are transferred by a nutritional way (some infections diseases and intestinal worms, alimentary poisonings). 5. Alimentary intolerance - atypical reaction to nutrition, for example alimentary allergy, idiosyncrasy. 2. The secondary illnesses of insufficiency or excessive nutrition, which is developed as complication on a background of wearisome illnesses (surgical, infectious, oncology and others.) 3. Disease of multifactor nature that very much frequently develops on a background of genetic predilection, for example, atherosclerosis, gout, idiopathic hypertension, etc.

Function of nutritionBody building and repair Provision of energyMaintenance and regulation of tissue functions

CLASSIFICATION OF FOODS

Classification by predominant functions:Energy-giving foods. These constitute fats and carbohydrates. They are also called protein sparer. Proteins also produce energy to some extent. Cereals, roots and tubers, dried fruits, sugars and fats belong to this group. They supply heat and energy to the body.

Body building foods. These are foods rich in proteins, mineral salts and water. Milk, meat, fish, pulses, oilseeds and nuts fall in this category.

Protective foods. These constitute inorganic salts, vitamins and minerals. They include proteins and water. Milk, eggs, liver, green leafy vegetables and fruits are included in this group. They build our bones, teeth, muscles, soft tissues, blood and other body fluids. They provide material for repair in the body as wear and tear goes on constant.

2. Classification by origin:Foods of animal originFoods of vegetable origin

3. Classification by chemical composition:ProteinsFatsCarbohydratesVitaminsMinerals4. Classification by nutritive value:Cereals and milletsPulses (legumes)VegetablesNuts and oilseedsFruitsAnimal foodsFats and oilsSugar and jaggeryCondiments and spicesMiscellaneous foods

Balanced diet is one, which will meet a person's caloric need and contain all nutrients, particularly proteins, and vitamins. In addition, the food should satisfy the taste and desire of a person and should have enough roughage to promote the peristalsis. Balanced diet should have 50-60 % carbohydrates 30-35 % fats and 10-15 % proteins with necessary vitamins and minerals. A balanced diet must contain foods from the above three groups.

Importance of the main components of food in nutrition of the man

Nutrients are organic and inorganic complexes contained in food. There are about 50 different nutrients which are normally supplied through the foods we eat. Each nutrient has specific functions in the body. Most natural foods contain more than one nutrient. These may be divided into :(i) Macronutrients: These are proteins, fats and carbohydrates which are often called "proximate principles" because they form the main bulk of food. (ii) Micronutrients : These are vitamins and minerals. They are called micronutrients because they are required in small amounts which may vary from a fraction of a milligram to several grams.

PROTEINSThe word "protein" means that which is of first importance. Indeed they are of the greatest importance in human nutrition. Proteins are composed of carbon, hydrogen, oxygen, nitrogen and sulphur in varying amounts. Some proteins also contain phosphorus and iron and occasionally other elements. Proteins differ from carbohydrate and fat in the respect that they contain nitrogen. Proteins are made up of simpler substances, called amino acids. These are the building blocks of proteinSome 22 amino acids are stated to be needed by the human body, out of which eight are called "essential".

Proteins are needed by the body:For growth and development: They furnish the building material, i.e. the amino acids from which the body proteins are synthesized.For repair of body tissues and their maintenance: It has been shown that the body proteins are constantly being broken down; they have to be replaced for which fresh protein intake is required.For synthesis of antibodies, enzymes and hormones: Antibodies, enzymes and hormones contain protein. The body requires protein to produce them.Proteins can also furnish energy to the body, but generally the body depends for its energy on carbohydrates and fats rather than proteins.

Sources of proteinAnimal sources:Plant sources:

Protein requirementsDoctors recommended 1,0 g. protein/kg body weight for an adult. Daily allowances recommended by experts of the World Health Organization (Geneva, 1976) is 37 g of protein per day for the standard man with mass of body 65 kg for professions of average hardness (II group) and 29 g of protein for the standard woman with body mass 55 kg.

Effects of protein deficiency:The effects of protein deficiency may summarized as below.During pregnancy: Still birth, low birth weight,anemia

Infancy and early childhood: Marasmus, kwashiorkor, mental retardation, stunted growth and development

Effects of protein deficiency:Adults: Loss of weight, underweight, poor musculature, anemia, increased susceptibility to infection, frequent loose stools, general lethargy, incapacity to sustained work, delay in wound healing, cirrhosis of liver, oedema, ascitis, etc.

Fats are composed chemically of carbon, hydrogen and oxygen, only in different proportion than they are contained in carbohydrates. There is less of oxygen in fats than in carbohydrates. Fats are a form of concentrated food and like carbohydrates, they are used as body fuels for the production of heat and energy. As fats are not soluble in water, the process of digestion changes the fat into an emulsion form for their absorption into the body. Liquid fats and those which melt at body temperature are somewhat better digested than those which are much harder.

Fats serve the following functions: Dietary fat is a concentrated source of energy. One gram of fat supplies 9 calories of energy.

Fats are carriers of fat-soluble vitamins, e.g., vitamins A, D, E and K.

Dietary fat supplies "essential fatty acids". Linoleic acid, one of the essential fatty acids, prevents scaly skin formation.

The fat layer below the skin plays an important role in maintaining our body temperature.

Fats provide support for many organs in the body such as heart, kidney, intestine etc.

Foods containing fats are tasty.

Vegetable sources: These are various vegetable oils such as groundnut, gingely, mustard, cottonseed, safflower (kardi) and coconut oil.Animal sources: These are ghee, butter, fat of meat, fish oils, etc.

CARBOHYDRATES

Chemically carbohydrates are composed of carbon, hydrogen and oxygen as the name implies. Polysaccharides are various starches which are converted into two molecules saccharides i.e. cane sugar, beet sugar, milk sugar and malt sugar. These on further, glucose and digestion change into single molecule monosaccharides fructose.

Foods that are high in carbohydrates: Breads, pastas, beans, potatoes, bran, rice and cereals.

The original source of all starches and sugars is green plants. When plants have excessive sugar and they need to store it, as reserve supply of food, plant body is capable of changing its sugar into starch. Carbohydrates are abundantly present in food. All carbohydrates have to be changed into glucose and fructose before they can be absorbed into the body.

1 gm of carbohydrates yields 4.1 calories of heat.The daily requirement of carbohydrates varies from 50 to 60% of total energy intake.The carbohydrates are chief sources of energy. In the active muscles, the glucose is oxidized for the production of energy and warmth. Glucose which cannot be used immediately, is converted into glycogen and stored in the liver and muscles or converted into fat and stored under the skin.

Sugars:Monosaccharides: glucose, fructose, galactose.(b) Disaccharides: Sucrose, lactose, maltose.(c) Cellulose: This is the tough fibrous lining found in vegetables, fruits, cereal, etc. It is hard to digest and has no nutritive value. However, cellulose acts as "roughage" and prevents constipation.Starches: These are present in cereals (rice, wheat); roots and tubers (potatoes).There are three main sources of carbohydrate:

VITAMINSThese are complex organic substances contained in food and are very essential for the normal growth and nutrition of animals. In fact, they are vital accessory food factors required for the maintenance of optimum, health. They are present in various foods in minute quantities and diet devoid of vitamins, if taken for some period, gives rise to certain diseases known as deficiency diseases and may ultimately even cause death. They do not supply energy but are simply protective foods.

vitamins Water-soluble VitaminsNiacin (B3)Fat -soluble Vitamins Riboflavin (B2)Folic acidE (tocopherol)A (retinol)D (calciferol)K (menadione)Pyridoxine (B6)Thiamine (B1)Pantothenic acid Cobalamin (B12)Ascorbic acid

Nutritional Diseases:

1. Protein Calorie Malnutrition (PCM). (i) Kwashiorkor. It results from consumption of very low protein in diets of low biological values, yet providing just enough energy to satisfy the needs of the child. This condition is usually seen in children between the age group of 1-4 years. This symptom is characterized by pitting oedema, anemia, retarded growth, loss of appetite, diarrhoea, scanty hair growth...(ii) Marasmus. It is a clinical condition of protein energy malnutrition, primarily due to total deprivation of the requisite calories required by the body. It usually occurs in the age group of 1/2 to 5 years. This syndrome is characterized by failure to gain weight, wasting of muscles and of subcutaneous fat. The child feels good appetite but is irritable.(iii) Marasmic-Kwashiorkor. Patients suffering from Marasmic-Kwashiorkor show clinical symptoms of both Marasmus and Kwashiorkor.

2. Protein Deficiency in Adults. Protein deficiency in adults is also quite prevalent in poverty areas. Protein deficiency will result in adults having reduced weight, reduced subcutaneous fat, anaemia, greater susceptibility to infection, frequent loose motions,general lethargy, delay in healing of wounds oedema.

3. Mineral DeficienciesDeficiency of iodine in water and feed leads to goitre.

(ii) Lack of flourine ( < 0.5 ppm) in water leads to caries.

(iii) Calcium deficient diets lead to rickets and osteomalacia.(iv) Iron deficiency diets lead to anaemia, (v) There are other important minerals like copper, selenium etc. Usually their requirements are so little that deficiency conditions do not occur.

4. Vitamins Deficiencies Lack of vitamin A results in xerophthalmia, Bitot's spots, night blindness and keratomalacia.

(ii) B Complex: Deficiency of Thiamine leads to beri - beri.Niacin deficiency results in pellagra.Riboflavin deficiency symptoms are angular stomatitis, cheilosis, scrotal dermatitis and corneal vascularisation.

Other B Complex deficiencies also result in glossitis, cheilosis and angular stomatitis

(iii) Vitamin C deficiency leads to scurvy, spongy bleeding gums, haemorrhages in skin and other haemorrhages, (iv) Vitamin D deficiency result in rickets and osteomalacia.(v) Vitamin K deficiency leads to hypoprothrombinaemia, which further leads to haemorrhages.

5.Problems of Overnutrition (eating too much)Proteins/fats/carbohydratesCardiovascular disease (Leading cause of death in the western world); a primary cause is thought to be ingestion of saturated fat and trans fat Some cancers Diabetes mellitus Insulin resistance Obesity The main features of obesity are overweight and fatness. It is mostly caused by overeating and intake of abundance of caloriesMetabolic syndrome VitaminsVitamin poisoning

(i) Hypervitaminosis A is at times caused by excess of vitamin A therapy. The manifestation are headache, nausea, vomiting, irritability and anorexia. Carotenaemia is also caused due to excessive consumption of carrots which is characterised by yellow skin with normal conjunctiva

(ii) The toxic manifestations of hypervitaminosis D are anorexia, nausea, vomiting, thirst, polyuria and drowsiness. Calcium and phosphorus levels in serum and urine are raised. Calcium may be deposited in many tissues also

(iii) Fluorosis occurs if fluorine is available > 1,5 mg in water. It is characterised by (a) dental fluorosis, i.e., mottled enamel of teeth and (b) skeletal fluorosis i.e., dense bone formation, severe spondylitis and even calcifications of ligaments of spine and tendinous inflamation of other muscles in severe cases.

Food allergiesSome people have allergies or sensitivities to foods which are not problematic to most people. This occurs when a person's immune system mistakes a certain food protein for a harmful foreign agent and attacks it. About 2% of adults and 8% of children have a food allergy.Commonly food allergens are gluten, corn, shellfish (mollusks), peanuts, and soy. Most patients present with diarrhea after ingesting certain foodstuffs, skin symptoms (rashes), bloating, vomiting and regurgitation. The digestive complaints usually develop within half an hour of ingesting the allergen.Rarely, the food allergy chelce can lead to anaphylactic shock: hypotension (low blood pressure) and loss of consciousness. This is a medical emergency. An allergen associated with this type of reaction is peanut, although latex products can induce similar reactions.

The hygienic characteristics of some food-stuff and their sanitary examination

WheatIt is the most important of all cereals and is extensively used all over the world. It contains 60-70 % starch, 8-12 % gluten and 15 % water. The seeds have an outer envelope called pericarp, which is very hard. It is composed mainly of cellulose and mineral matter and forms about 13 % of the grain. A middle layer called endosperm or kernel consists chiefly of starch. It forms 85 % of the grain. The germ or embryo forms about 1.5 % of the entire grain. It is rich in protein and fat. Flour is prepared by grinding up wheat.

Rice In fact, it forms the staple article of diet for half the population of the world. In composition, it is poorest in proteins, fats and mineral matter, out of all the cereals and has no cellulose contents or roughage. Its chief constituent is starch, which is in a very digestible form. It is digested within 3-4 hours. Being rich in starch it is eaten with nitrogenous and fatty substances, like pulses, fish, ghee etc., to supply the deficiency in proteins and fats. The bulkiness of rice eaters' diet gives rise to two important consequences: (i) it tends to prevent the absorption from the intestines of the proteins and vitamins contained in other foods eaten with it, as dais or pulses (ii) it is apt to cause distension of the stomach and bowels with fermentation of their contents, thus result in indigestion and bowel complaints. The outer layer or pericarp contains vitamin B1 and its complete removal may give rise to beri-beri in rice eating population. Rice does not contain vitamins A, C and D.

Barley. It is very nutritious and is characterized by its richness in mineral salts and fat but is poor in gluten, so it is unsuited for making bread.

Maize. It is as nutritious as wheat, and richer in fats than all cereals except oats. It contains 10 % proteins, 65 % carbohydrates, 5 % fats, 1-2 % salts and 14 % water. Maize is poor in certain amino acidssuch as tryptophane. It is deficient in vitamins, the anti-scorbic and anti-pellagra factors being absent and an exclusive use of maize may cause pellagra.

Oats or Jao. These are highly nutritious. They are deficient in vitamins A and D and gluten. Oats are used as oatmeal porridge and should be eaten with plenty of milk.

PulsesThese are mostly legumes and are richer in nitrogenous substances that other vegetable foods. Pulses include peas, beans, and lentils. Owing to their richness in proteins, they are called "poor man's meat". Compared to meat, pulses are deficient in fat. Pulses also contain a good deal of carbohydrates If their fresh state they contain vitamins A, B, and C, but when dried they lose vitamin C. Soya BeanIt is the richest form of vegetable proteins but with low fat content, a large amount of mineral matter and almost complete absence of starch. Iron content of soya beans varies from 7-30 mg. per 100 gms. The protein is of good quality and easily digestible. It contains large quantities of vitamin B1 but no vitamin C and D. A milk from soya bean is prepared to resemble more or less the composition of cow's milk. It contains absolutely no cholesterol. The high fibre content of soya milk helps relieve constipation, while high mineral protein and vitamin (especially B complex) levels provide "ideal" nutrition.

Roots and Tubers. They exist chiefly in the form of starch which is about 80 % proteins and fats being practically absent. They contain some mineral matters which are mainly salts of potash. The common form of tubers are carrots, potatoes, beet-root, radish, onions, arrow-root, sago and tapioca.Green Vegetables. They have little nutritive value, but form an important article of diet on account of the presence of vitamins and mineral salts of sodium, calcium and chlorine, which they contain. In composition they consist of 90 % water, 2 % nitrogenous substance or proteins, 4 % starch and % fats. Potatoes are rich in carbohydrates and contain starch 22 %, protein 2 % and a trace of fat (0.16 %). They are a good source of vitamins B and C and contain iron and phosphorus; that is why they are universally used as wholesome and palatable dietary articles having much nutritive value. They contain large amount of alkaline salts which act as "buffers" and maintain the alkalinity of the blood. They supply vitamins A, B1, B2 and C and give relish to the food, so their inclusion is essential in an ideal dietary. Green vegetables are rich in cellulose, so add bulk and are of value in curing chronic constipation. So far as possible, they should be eaten raw as salad.

FruitsFruits contain a large amount of sugar, vegetable acids and salts. These are protective foods. According to their nutritive value fruits have been divided into food fruits and flavouring fruits.Food fruits are those which afford nutriment, and include bananas, dates, figs, grapes, mangoes etc. Their nutritive value depends on the presence of carbohydrates, which exist in the form of sugar and commonly known as levulose or fruit sugar. Certain fruits such as lemons and oranges are rich in potassium salts, lime and magnesia and contain vitamin C.The fruits are valuable because:They have cooling effect and quench thirst.They contain important mineral salts of potash combined with vegetable salts.They have anti-scorbutic properties being the richest sources of vitamin C and for this reason they are included in children's dietary. They prevent scurvy.They prevent constipation.

Nuts. They differ from fruits as they have higher calorific and nutritive value, being rich in proteins and fats. The common nuts are almonds, cocoa nuts, ground nuts, walnuts etc. They are rich in vitamin B but contain very little vitamin A and no vitamin C.

Meat It consists of muscle-fibres held together by connective tissues. The fibres of meat contain muscle plasma or muscle-juice. It contains 1 to 2 % salts which are chiefly chlorides and phosphates of potash. The proteins of meat which are present to the tune of about 17 to 20 % are myosin, muscle-albumen and haemoglobin. Fat (10 to 20 %) is often embedded in the connective tissues of meat.Inspection of Meat. Anti-mortem inspection of animals should be done, wherever possible and the animals should be rejected, if they appear to be ill. The carcase should be inspected after slaughtering whole and also part by part and subsequently organ by organ. Mediastinal and bronchial lymphatic glands should be examined for evidence of tuberculosis. If the animal has suffered from jaundice, the flesh will have a yellow tinge.Characteristics of Good Meat. The muscle fibres are of deep red colour and marbelled with fat. The reaction should be acidic. It should be firm, elastic to touch. It should have little or no odour as diseased meat emits odour of putrefaction or sickly smell. The fat should be firm and of whitish or yellowish grey colour. Lymphatic glands should be free from all diseases. Any diseased condition, i.e., cysts of tapeworms etc., should not be present.

Unsound Meat. It is that meat which has begun to putrefy. It becomes soft, moist, pale and often has greenish colour. The reaction becomes alkaline dour of putrefaction may commence in the deeper part of the meat especially near the bones and so the odour may not be apparent from the outer surface. Therefore, in case of suspected meat, it is advisable to push an iron skewer deep into the meat; pull it out and smell it. The smell should be sweet and agreeable. The juice should be reddish and acidic, since alkalinity is an indication of decomposition. Putrified meat is extremely dangerous, as poisonous substances get developed, which introduce sudden and fatal illnesses due to ptomaine poisoning.

Diseased Meat The flesh of animals killed by accident, lightning or those who happen to be suffering from diseases like anthrax, rabies, glanders, general tuberculosis etc., should be condemned. The diseased meat should be condemned and prevented from sending into the market. The chief diseases of animals are:Tuberculosis.Cysticercus. Trichinella Spiralis.Actinomycosis or Ray Fungus.Distomum Hepaticum of Liver Flukes.

Fish It is easily digested and is assimiable. It has a high nutritive value, though not so stimulating as meat, but generally it is less rich in fats and contains more calcium than ordinary meat. It has all the vitamins except vitamin C. Fish liver is a rich source of vitamins A and D. Sea fish is a rich source of iodine.There are two kinds of fish: Lean fish. It consists of small fibres and contains fat below 2 %. It is easily digested. Fat fish. It consists of medium or large fibres with fat content of 2.5% or more. It is somewhat difficult to digest.Characteristics of Good Fish A fish should have bright pink gills, firm glistening scales and prominent lustrous eyes. It should have a bright and glistening skin with a covering of clear slippery mucous. It should be free from any disagreeable odour. When held flat on hand by head, the tail should not droop. It should not feel soft or leave an impression or depressed mark when pressed by a finger. Its skin should be intact and scales should not be easily detachable. If not eviscerated a sound dead fish sinks in water.

A decaying fish has dull grey sunken eyes, grey muddy gills, the scales become detached and have a characteristic putrefying smell. It may cause ptomaine poisoning. It floats in water with belly up, A putrefying fish shows dark blood or dark tarry liquid on cutting and its body becomes flaccid. A large tapeworm called Dibothriocephaluslatus is conveyed to man by eating insufficiently cooked fish. Fish poisoning may occur due to toxins produced by Cl. botulinus. Its decomposition may give rise to ptomaine poisoning. It may be found that some persons possess idiosyncracies especially to muscles, which are said to cause poisoning by mytilo toxin. The chief symptoms produced are dyspepsia, urticaria, swelling of tongue, numbness of limbs, weak irregular pulse etc.

On Inspection. There should be no indentations, holes, soldering defects or signs of gross ill usage. It should not be rusty. It should have concave ends and not be bulging or blowing out indicating putrefaction and formation of hydrogen gas in acidic medium. A collapsed tin signifies too much vacuum. All leaking and non-airtight tins should be discarded.On Palpation. If putrefaction has set in and gas has formed it gives a springy feel with a sense of resistance. It so happens particularly, when air has entered into the tin through a leaking hole and the vacuum is lost.On Percussion. If the note is tympanitic, it indicates unsound tin due to formation of gas, while a dull note indicates a sound tin.On Shaking. A sound tin will produce no sound, but if the contents are putrefied and are partially liquid then a loose sloppy sound will be detected.Tinned Meat and Fish. They are commonly used. It is very essential to see that meat and fish in tins are wholesome, not old and putrefied. The tins should be carefully examined before consumption in the following ways:

It consists of an outer shell with its interior white and yolk. The shell consists of carbonate of lime, the white is made up wholly of proteins, the chief being egg albumen and the yolk contains less proteins and a large amount of fat. Besides, it contains lecithin, vitalin and the organic compounds of phosphorus, lime, and iron. It is rich in calcium salts, anti- neuritic and anit-rachatic vitamins. Eggs A egg's weighs approximately 56.70 gms and consists of 10 % outer covering or shell, 60 % white, and 30 % yolk. It is a food containing all the proximate principles of food, except carbohydrates necessary for the growth and development of the body. It is a protective food containing first-class proteins with all the essential amino acids and have the highest nutritive value among dietary proteins. In view of the presence of sulphur in the white of egg, they are considered as acid forming foods and resemble meat in this respect.

Yolk of egg is a valubale food for anaemic patients, since it contains iron which is very easily digested and assimilated in the body. Since the fat present in the yolk of eggs is in emulsified form, just like milk, it is easily digested and is almost completely absorbed in the intestines; only 3 % of residue is left.

Freshness of eggs can be tested

by holding them in the hand in front of a candle in the dark. Fresh ones being more transparent in the centre and stale ones are transparent at their extremities. This process of testing the eggs is known as Candling.

(2) By putting them in 10 % salt solution; fresh eggs will sink, whereas stale ones will float.

MilkIt is a food material of special importance. It is almost complete, an ideal food and contains most of the proximate principles of a well balanced diet required for human body. It is thus the nearest approach to perfect food. It forms the only diet of children to the age of a year or so. It is the best source of calcium in diet both on account of quality and the valuable assimilable form in which it exists. It provides proteins of high biological value to the body.

3. Fats: 3,5 to 4 % in the form of glycerides in emulsified form. Milk fat is a good source of vitamins A and D When milk is allowed to stand for sometime, fat rises to the surface as cream. Chemically milk fat consists of myristin, olein, palmitin and stearin.4. Vitamins: It contains all the vitamins except vitamin E. In summer, cows, if fed on grass, produce milk containing large amount of vitamins B, C and D. But in winter, amount of vitamins A and D in milk is much reduced.5. Mineral Salts: Phosphates and chlorides of calcium, potassium and sodium. It is poor in iron.Milk contains the following proximate principles:1. Proteins: 3,5% of total weight, consisting of 3 % Caseinogen, 0,4 % Lact albumen, and 0,1% Lacto-globulin. Milk proteins are of high biological value. Cow's milk is rich in casein, and human milk in Lactalbumi2. Carbohydrates: The carbohydrate in all milks is lactose or milk sugar (4 to 5%). Human milk contains more lactose than cow's milk

Average specific gravity of cow's milk is 1.032. Lactometer is used to determine the specific gravity.Solids other than fat are estimated by evaporation to complete dryness, a known weight of milk and then weighing total solids and subtracting therefrom the fat previously determined from percentage of solids, which gives percentage of solids other than fat.Milk-borne diseases. The important milk-borne diseases are:1. Directly from the milch animal: Tuberculosis,BrucellosisStreptocobbsl infectionMalta fever Anthrax2. Inderectly from the human handler or environmentTyphoid and paratyphoid fevers;Cholera,Dysentery, Diphtheria, Viral hepatitis

Methods of Preservation of MilkThese are as follows:(1) Boiling is ancient method of rendering the milk safe for human consumption. (2) Pasteurisation. According to WHO, pasteurisation may be defined as the heating of milk to such temperatures and for such periods of time, as are required to destroy any pathogenic organisms that may be present, while causing minimal changes in the composition, flavour and nutritive value of milk.There are various methods of pasteurisation of milk. Some of them are as follows:Holder or Vat Method. In this method milk is heated and kept at 63 to 66C for 30 minutes and then quickly cooled to below 5 C. High Temperature and Short Time method: milk is heated rapidly to a temperature of 72 C and then quickly cooled to below 5 C. Ultra High Temperature method: The temperature of milk is raised to 125 to 150 C for a few seconds only and then rapidly cooled

Difference b|w pasteurization and boiling

3. Sterilisation. This is done by raising the temperature to 100C and then by maintaining it for 15 minutes in closed sterilised vessels. It kills all micro-organisms and their spores. The disadvantages is that vitamin C and B are destroyed to one-half and one-third respectively of their original content. The biological value of proteins is said to be slightly reduced. It is unsuitable for feeding infants.4. Drying or Desiccation The milk prepared from this powder is of uniform composition, free from all dangerous organisms and easily digested by infants, as the curd formed in their stomach is more flocculent and finely divided than that of the fresh cow's milk. The vitamin content of dried milk is variable. Vitamin C is reduced considerably. So when it is given to infants, orange juice or any other vitaminised preparation should be added to it.

Cream. It is prepared by allowing the milk to stand for a considerable time in the cold so that butter fat may rise to the top and then removing the top layer. The fat or cream may be separated from milk mechanically through a centrifuge machine known as a separator or it may be obtained by churning the curdled milk. Cream may contain about 50 % fat. Besides milk fat, cream contains proteins and lactose also.Butter: It is the most nutritious and easily digestible form of all fats. Good butter should neither be rancid nor have an unpleasant odour. Specific gravity of butter fat varies from 0.911 to 0.913. Its melting point is 35.8C. Its average composition should be:Water 12 - 15 %Fat 80 - 90 %Caseinogen 1 - 3 %Lactose 1%Ash 2-3%Salt and Vitamins -q.s.

Cheese. It is a very concentrated protein food and methods of making it vary considerably at different places. It is prepared by coagulating caseinogen of whole milk or skimmed milk with rennet. Cheeses differ by high content of protein (20-25 %), fat (25-30 %) and what is also important calcium and phosphor.

Depending on quality the food-stuff can be divided on such groups:1. Products of high quality - the products which may be used without restrictions. 2. Non-standard. The products, which have the certain deviations from requirements of state standards or specifications, but it does not interfere to their realization (for example, chicken eggs of mass less 40g etc.). 3. Conditionally suitable. It is products, which can be used after additional processing. 4. Substitutes (ersatz). The products with reduced value as natural substitutes, for example, barley and acorn coffee. They are allowed to realization, provided that the consumer would be informed, what kind product is offered to him. 5. Food Adulteration It is products, in which premeditatedly qualitative structure are changed to hide the certain disadvantages or sings of decay. Such products are forbidden to realize to the population. 6. Low-quality. The products concern to those, which are not suitable to nutrition in any way, that is, which have the expressed signs of decay (rotting, etc.).

Some of the common practices in different country includeRice and wheat: There are mixed with stone chips and gravel to incrase the bulk. Flour: Wheat flour is mixed with soap stone powder and cheaper flours such as maize flour; Milk: Removal of fat and addition of water, starch and skimmed milk, milk powder etc. are the common types of milk adulteration Butter is adulterated with other animal fats in Western countries and in India by other vegetable oils. Miscellaneous : Tea leaves are adulterated with old tea leaves, leather and saw dust. Coffee is adulterated with chicory. Honey is adulterated with sugar or jaggery and boiled with empty beehives. Papaya seeds are mixed with pepper. Powdered condiments and spices often contain an assortment of innumerable substances including horse dung and brick powder. Some forms of adulteration may not be very dangerous e.g., addition of water to milk, cheap edible oils to expensive ones, cheap flours to expensive ones etc. However, they may considerably reduce the nutritive value, contaminate the food (e.g. water to milk) and add toxins to the food (e.g., kesari dal flour to other flour and adulteration of edible oils with argemone oil and white mineral-oil, use of non-permitted colours in sweets and cordials, and that of lead chromate for spices etc.

Fortification and EnrichmentAddition of one or more dietary essentials to some foods in amounts which make the total content greater than that found in that particular food in its natural state is known as Fortification. It also includes addition of one or more dietary essentials which original food does not contain in its natural state. Enrichment means addition of dietary essentials to a food to restore the total content of the former. Some of the examples of fortification and enrichment are as follows:Addition of Vit. A and D to milk, addition of potassium iodate to common salt for endemic goitre areas, addition of iron and calcium to common salt is being considered by the Government of India, addition of synthetic aminoacids foods e.g., lysine to wheat flour etc.Supplementary Foods A number of cheap supplementary foods are being formulated, which can provide nutrients at low cost, as a supplement to the usual diet.

Food AdditivesFood additives are non-nutritious substances which are added intentionally to food, generally, in small quantities to improve its appearance, flavour, texture or storages properties.Food additives are generally used as food colours, antimicrobials, anti-oxidants and as stabilising, bleaching and maturing agents. Their use for a number of techinical processes such as the maintenance of the nutritive quality of food, enhancement of keeping quality, making food attractive to the consumers and providing essential aids to food processing, is well recognised. However, their abuse is creating serious public health problems, because they are sometimes used to deceive the consumer by disguising the faulty handling and processing techniques. Several food additives are under controversy about their safety; and some are dangerous to health, which are quite often used in spite of not being permitted by law.

BASES OF TREATMENT - PROPHYLACTIC NUTRITION

Treatment-prophylactic nutrition is a special nutrition for workers of harmful enterprises. The base of this nutrition is rational nutrition, which is structured according to metabolism of harmful substances in the human organism and curative action of some nutrients, which protect human organism from negative influence of chemical compounds and physical factors. Treatment-prophylactic nutrition is an obligate component of protective health-proving measures, directed on limitation of negative action of harmful factors on production on the organism.

Treatment-prophylactic treatment is directed on:

elimination of possibility of harmful substances penetration into internal medium of the organism from the digestive tract, meaning their binding in stomach and intestines;

quickening of excretion of harmful substances from the human organism;

increasing of general resistance of the organism towards harmful factors;

protection of certain, most damageable systems of the organism from harmful action of toxic substances;

quickening or on the opposite slowing down toxic substances metabolism in the organism (aiming to stop their income into internal medium).

In Ukraine there are 3 kinds of treatment-prophylactic nutrition on harmful enterprises:

Treatment-prophylactic ratios.Milk.Synthetic vitamin drugs.

Introduction of treatment-prophylactic nutrition as a rule follows after theoretical and medical-biological investigations directed on determination of mechanism of action of certain harmful substances and their combinations on the organism. Complex interrelations between components of the mixture are determined during studying of complex action of several toxic substances; as if they enter the organism together character of their toxic action may change (synergism or antagonism). After detoxic action of different nutritive products and substances is studied. It is proved that many nutrients have a considerable detoxicating action. Thus, pectin substances are able to bind heavy metals and radionuclide in digestive tract, preventing their absorption and entering internal medium of the organism. Sulfur containing amine acids methyonin, cystin, magnesium salts promote excretion of some toxic substances from the organism. Vitamins raise protective capabilities of the organism.

In case of constant poisonings with chemical substances their multiple influences on the organism is often performed, presented by damage of central and peripheral nervous system, internal organs (liver, kidneys, respiratory organs) and blood producing organs (anemia often develops). General result of the influence of all chemical substances on the organism is disordering of functional condition of liver, which leads to its inflammation (hepatitis), and after to cirrhosis.

Following principles are followed during organization of treatment-prophylactic nutrition:

As a usual result of influence of all chemical substances on the organism is disordering of liver function, so in treatment-prophylactic nutrition a considerable attention should be paid to nutrients and substances which increase functional condition of liver and limit consumption of substances and products which overload its work. Products, which increase functional condition of liver, are: milk, sour-milk products, cheese and cottage-cheese. Wide usage of milk products in treatment-prophylactic nutrition is explained by considerable contents of sulfur containing amine acids (methyonin, cystin), which protect liver from fat infiltration.

2. Quantity of fats should be limited as they speed up absorption of many chemical substances, most of which are fat-soluble substances.

3. Treatment-prophylactic nutrition should be provided by a necessary quantity of fruit and vegetables, which are the source of many water-soluble vitamins, carotene, microelements, pectin substances and fiber.

4. Treatment-prophylactic nutrition should have an alkali orientation. Disorder of acid-base balance of the organism to acidosis side leads to increasing of harmful substances income into blood, for example, lead, and moving to alkalosis side promotes accumulation of many toxic substances in the organism. Milk, milk products, fruit and vegetables possess alkaline properties.

5. Consumption of salt should be limited, since it promotes water retention in the organism.

6. Treatment-prophylactic nutrition should be provided based on general rational nutrition.

VEGETARIANISM

Vegetarianism is the practice of not consuming the flesh of any animal, with or without also eschewing other animal derivatives, such as dairy products or eggs. Some vegetarians choose to also refrain from wearing clothing which has involved the death of animals, such as leather, silk and fur. Veganism, sometimes called "strict vegetarianism", excludes all animal products from diet and attire, whether or not their production has involved the actual death of an animal (dairy, eggs, honey, wool, silk and down feathers). Vegetarians have varied motivations including religious, cultural, financial, ethical, environmental, and health concerns.

There are many different practices of vegetarianism. The following table summarizes the practices of various different types of vegetarian diet:

Foods allowed in the main vegetarian dietsDiet NameMeat (includes fish)EggsDairyLacto-ovo vegetarianismNoYesYesLacto vegetarianismNoNoYesOvo vegetarianismNoYesNoVeganismNoNoNo

Other dietary practices commonly associated with vegetarianism

Fruitarianism is a diet of only fruit, nuts, seeds, and other plant matter that can be gathered without harming the plant. Macrobiotic diet is a diet of mostly whole grains and beans, though it allows the consumption of fish. Natural hygiene in its classic form recommends a diet principally of raw vegan foods. Raw veganism is a diet of fresh fruit, nuts, seeds, and vegetables. Freeganism argues that all commodities produced under capitalism, not only those from animal sources, contribute to exploitation and avoid buying anything, including food. Freegans thus focus on acquiring foods and other commodities by means other than purchasing, including dumpster diving, foraging for wild plants, and gardening with intent to cause as little violence and ecological destruction as possible through their consumption. While many freegans are vegans or vegetarians, others will eat animal products recovered from dumpsters that would otherwise go to waste on the belief that doing this does not encourage further animal exploitation.

Vegetarian diets appeal to people for various reasons. For some people, religious and philosophical teachings prompt adherence to a vegetarian regimen. Other people seek health benefits. There is much to be said for most of us making our food choices in the direction of vegetarian principles, eating less meat and eggs and substituting foods of vegetable origin. Such choices will reduce the amount of fats, particularly the saturated ones, and increase the amount of fiber consumed. Although such choices will reduce the amount of protein we eat, most of us consume more protein than we need. At the same time, a poorly planned vegetarian diet can put you at risk for disorders such as vitamin B12 deficiency iron-deficiency anemia, growth retardation (in persons who have not yet achieved their full adult growth), and osteoporosis. Careful planning is the key to such a diet. Because many of the nutrients a human body needs are found most readily in animal products, finding substitutes requires effort.

There are various degrees of food restrictions in vegetarian diets. Total vegetarians, known as vegans, restrict their foods to those of plant origin only. Fruitarians further restrict their foods to only raw or dried fruits and nuts, honey, and olive oil. Lacto-vegetarians eat foods of plant origin plus milk and other dairy products. Lacto-ovovegetarians eat plant foods, milk and other dairy products, and eggs. Obviously, the question of the nutritional adequacy of a particular vegetarian regimen depends on the extent of food restrictions. Also, children and teenagers, pregnant and lactating women, and people recovering from a serious illness or injury who are vegetarians need to take precautions to ensure that all of their body's needs are met. Such people should follow a vegetarian regimen only with the careful supervision of an experienced, registered dietitian.Protein is of some concern when planning a strict vegetarian diet. Protein found in foods of plant origin tends to have only small amounts of one or more essential amino acids. Protein from animal sources contains essential amino acids in an optimal proportion.

Grains and cereals with ingredients including wheat, com, oats, and rice provide some essential amino acids, while legumes such as peas, peanuts, and dry beans provide others. When, during the course of a day, you combine a grain with a legume, or cornmeal with beans, you have a more nearly complete set of essential amino acids.Another important nutrient in the vegetarian diet is vitamin B12. Vegetarians who consume milk or eggs will get enough of this vitamin. Those who do not can eat foods artificially enriched with vitamin B12. Some commercial foods made from soybeans and other plant proteins are fortified with vitamin B12. Vegetarians who eat eggs and dairy products also usually receive enough calcium and riboflavin, but the vegan has to devise special dietary strategies. Many foods of plant origin contain calcium, but they may not be as easily used by the body because of the presence of fiber and oxalic acid in the foods. Oxalic acid and fiber may interfere with the body's ability to use the calcium present in the foods. Thus, if you are a strict vegetarian, you may need calcium supplements.

Vitamin D, iron, and zinc are other nutritional elements needing special attention in the vegetarian diet. Most of us obtain vitamin D through fortified milk and exposure of our skin to sunlight. If you do not drink milk, you must rely on sunlight or on a vitamin supplement. However, children and pregnant and lactating women who are vegetarians should not rely solely on sunlight but should take a supplement.

The high fiber content of most vegetarian diets tends to impair the absorption of iron and zinc. Good sources of iron include enriched cereals and grains, legumes, dates, prunes, raisins, and leafy green vegetables. You can enhance absorption of the iron in vegetables by including citrus fruit or juice or other foods high in vitamin C with meals :hat contain plant sources of iron. Vitamin C helps increase the iron absorption from plant roods. Good sources of zinc include legumes and nuts.