The Main Parameters of Milk According to the State Standard

v Organoleptic properties:

Ø Colour — white with yellowish shade

Ø Smell and taste — specific lactic,

Ø Consistence — it should not be watery or dense

v Physical properties:

Ø Density at 20°C — 1.028-1.034

Ø Dry residue — 11–12.5%.

v Chemical properties:

Ø Fat content — 2.5-3.2 %

Ø Acidity: normal acidity — 16-22° Terner (16-19°T — fresh milk, 20-22°T — fresh enough, over 23°T — not fresh). Diluted with water milk has acidity below 16°T.

v Bacteriological properties:

Ø Pasteurized milk in bottles and packages:

§ Common microbial number per ml — 75,000

§ Coli-index per ml — 0.3

v Pasteurized milk in flasks and tanks

§ Common microbial number per ml — 300,000

§ Coli-index per ml — 0.3

v Tests on Milk Falsification

Ø Evaluation of starch addition (–)

Ø Determination of soda (–)

Falsified milk has the following parameters:

The skim milk: colour — of bluish shade, watery consistence, the dry residue is less than 11%, density of milk at 20°C is over 1.034.

Milk diluted with water:colour — of bluish shade, watery consistence, the dry residue is less than 11%, milk density at 20°C is less than 1.028, acidity — below 16°T.

Addition of soda.Soda is added to milk if its acidity is over 23°T (not fresh milk). Thus acidity is lowered. Rosolic acid is added to falsified milk (+ Test for determination of soda).

Addition of starch.Starch is added to milk diluted with water in order to increase the density and dry residue of milk. Solution of iodine is added to falsified milk (+ Testfor determination of starch).

Recommendations for practical classes

A sample of milk in a cylinder (200 ml) is given to each student for him to investigate and make the conclusion about its quality.

Protocol

of Independent Work on Hygienic Examination of Milk Sample

1. Organoleptic properties:

Colour ________________________________________________________________

Smell ________________________________________________________________

Taste _________________________________________________________________

Consistence __________________________________________________________

2.    Density of milk: ______________________________________ The readings of lactodensimeter ____________________________________________________________

Temperature __________________________________________________________

3.    Fat content of milk — _____________________________________________

4.    Dry residue — _____________________________________________________

5.    Acidity — ___________________________________________________________

Thus, the given sample of milk should be estimated as ___________________ according to the classifica­tion of product quality, because: ____________________________ (to enumerate parameters which do not correspond to the State Standard and possible causes of deviations).

 

Example 1

1. Your conclusion about the sample of pasteurized milk in bottles

Results of analysis:

Colour	White-yellowish
Odour	Standard
Fat content	2.5%
Temperature	24°   24° C
Density of milk	1.030
Acidity	25°T
Number of bacteria	25000 /ml
Coli-index	2
Starches For definition of soda (—)	-
Soda For definition of soda (—)	-

 

Problem Solving

1. Temperature of milk = 24° C (above 20ºС).

24° C — 20° C = 4° C

4° C ´ 0.0002 = 0.0008

2. The density of milk at 20° C = 1.030 + 0.0008 = 1.0308 (Normal density)

Normal density of milk at 20°C = 1.028 — 1.034

3. Acidity — 25°T (above normal acidity). Normal acidity = 16-22° T

4. The rest of indexes (colour, odour, fat content, number of bacteria, Coli-index) are normal.

Conclusion

Milk may refer to conditionally suitable foods. It may be used for production of curd, cheese, kefir, yoghurt.

Example 2

1. Your conclusion about the sample of pasteurized milk in bottles

Results of analysis:

Colour	Bluish shade
Odour	Standard
Consistence	Watery
Fat content	1.9 %
Temperature	10оС
Density of milk	1.029
Acidity	19°T
Number of bacteria	25000 /ml
Coli-index	2
Starches For definition of soda (—)
Soda For definition of soda (—)

 

Problem Solving

1. Temperature of milk = 10° C (less than 20ºС).

20° C — 10° C = 10° C

10° C ´ 0.0002 = 0.002

2. Density of milk at 20° C = 1.029 — 0.002 = 1.027 (less than normal density)

Normal density of milk at 20°C is 1.028-1.034

3. Fat content — 1.9 % (less than normal value of fat). Normal fat content of milk = 2.5–3.2 %

4. Colour — bluish shade. Normal colour of milk — white-yellowish.

5. Consistence — watery. Normal consistence should not be watery or dense

6. The rest of indexes (odour, number of bacteria, Coli-index, acidity) are normal.

Conclusion

Milk may refer to falsified products (milk diluted with water). It cannot be utilized.

Self-control Test

1. As a result of veterinary inspection of animals on a milk farm 20 cows with a positive reaction to tuberculosis have been revealed. Identify the possibility of using milk of such animals for nutrition.

* A. It can be used after pasteurization at 85°C during 30 minutes

B. It can be used without any preliminary processing and restrictions

C. It can be used for calves

D. It can be used for technical recycling

E. It should be destructed

 

2. A student has the following devices: Geiger’s counter, Eber’s counter, Krotov’s device, Mishchuk’s device, Eber’s device. What device should be used for evaluation of meat quality?

* A. Eber’s counter

B. Geiger’s counter

C. Mishchuk’s device

D. Krotov’s device

E. Eber’s device

 

3. In the market the milk is sold which is delivered in flasks. Smell and taste of milk are usual, colour is white with bluish shade, density — 1.015, fat content — 2 %. Acidy is 15° Terner. The extraneous impurity is absent. Estimate the quality of milk.

A. Milk is not fresh

B. Surrogated milk

* C. Falsified milk

D. Milk of good quality

E. Conditionally suitable milk

 

4. A sample of milk has been taken to laboratory for examination. The following data has been established: colour, smell — without features, taste — characteristic of milk, density — 1.038, acidity — 35° Terner, fat content — 3.2 %. Identify the degree of milk quality.

A. Substandard milk

B. Milk of good quality

* C. Conditionally suitable milk

D. Milk of reduced quality

E. Falsified milk

Problem Solving

1. The analysis findings of a milk sample are as follows: colour, smell, taste are usual. Density -1.033 at 30˚С, fat content — 2.6 %, acidity — 20˚ Тurner. Give a hygienic estimation of milk.

2. The analysis findings of a milk sample are: smell, taste — dairy, colour — white with a bluish shade, consistence — liquid. Density — 1.033 at 8˚С, fat content — 2.3 %, acidity — 20˚ Тurner. Give a hygienic estimation.

3. A milk sample from a tank shows: taste, smell — dairy, consistence — usual. Acidity — 17˚ Тurner. Density at 22˚С — 1.032. Fat content — 3.2 %. Reaction to starch and soda — negative. Total number of bacteria in 1 ml — 120,000. Give a hygienic estimation of milk.

Standard Answers:

1. Density at 20˚С is 1.035 (normal). Fat content is increased. As density is normal, dilution with water is excluded. The milk corresponds to standard. The conclusion: milk is of good quality.

2. Density at 20˚С is 1.029 (corresponds to standard). Fat content is decreased. As density is not increased, only depriving of fat is excluded; as density is not reduced, only dilution with water is excluded. The milk is simultaneously deprived of fat and diluted. The conclusion is: the milk is falsified.

3. Milk is of good quality, standard (bacteriological parameters of milk in flasks and tank — 300,000 per ml), density at 20˚С — 1.032.

 

Theme No 4.

Principles of Rational Nutrition. Prevention of Alimentary Diseases

Nutrition hygieneis a section of hygiene studying the influence of factors connected with nutrition on a human organism and developing recommendations for a balanced diet. A part of nutrition hygiene is nutriology — a science about nutrients (food substances).

According to WHO’s data, about 70 % of all diseases are directly or indirectly caused by a wrong nutrition or deterioration of food quality.

 

 

The basic sections of nutrition hygiene are the following:

· A rational nutrition is nutrition of a healthy person for maintaining and improving his health,

· A medical or dietary nutrition is for treatment of patients,

· A medical-prophylactic nutrition includes special diets for those working in harmful conditions, i.e. with chemical substances, radiation, etc.

· A preventive nutrition is for people with risk factors of development of diseases (atherosclerosis, diabetes, etc.).

Table 11

Classification of Types of Nutrition According to Purpose and Biological Effect

Type of nutrition	Purpose	Group	Biological effect
rational	prophylaxis of nutritional diseases	healthy people	non-specific
preventive	prophylaxis of diseases of a multifactor nature	risk groups of diabetes, etc.	specific
medical-prophylactic	prophylaxis of occupational diseases	people working in harmful conditions	protective
medical (dietary)	correction of metaboliс disturbances	patients	pharmacological

Classification of Alimentary and Alimentary-Conditioned Diseases

· Primary (exogenic) alimentary diseases. They are connected with insufficient or surplus nutrients or energy in diet. Their main feature is that aetiology, pathogenesis, symptomatology, prevention and treatment are connected only with nutrition.

· Secondary аlimentary-conditioned diseases. They are caused by diseases of organs and systems resulting in disturbances of food assimilation, increase of disintegration and consumption of nutrients. They may be infectious, surgical, oncologic illnesses. To these also endogenic avitaminoses, cerebral, hypothalamic, endocrinic adiposity or dystrophy refer.

The differential diagnostics of the 1st and 2nd group is very important for the doctor, because their therapeutic approach is completely different: in the first group only the correction of nutrition is necessary, while in the second — the treatment of a primary disease plus dietetic therapy, application of biologically active additives (BAA) are required.

· Diseases of multifactorial etiology, including the alimentary factor. They develop on a background of genetic predisposition, nervous-emotional causes and other factors, such as atherosclerosis, hypertension, urolithiases and cholelithic diseases, gout, gastrointestinal tract diseases, oncopathology, diabetes mellitus. In occurrence of these diseases nutrition is a risk factor, but not the only reason. Prophylaxis is a preventive nutrition, dietetic therapy at the developed pathology.

· Diseases connected with availability of harmful factors in food. These are food poisonings, intestinal infections, helminthiases. Their prevention is control of food quality.

· Food intolerance is aset of clinical reactions to food: a food allergy (immunopathology), pseudo-allergy (individual reactions to separate substances), idiosyncrasy of food owing to enzymopathies.

Classification of Alimentary Diseases (I group)

v Diseases and syndromes of malnutrition:

Ø Protein-calorie deficiency (PCD) of various degree, alimentary marasmus, physical development delay owing to PCD.

Ø Protein deficiency, including kwashiorkor (infantile pellagra)

Ø Avitaminoses.

Ø Mineral deficiency: iron-deficiency anemia, endemic goiter (hypothyroidism), caries, hypozincosis, hyposelenosis, etc.

v Diseases and syndromes of excess nutrition:

Ø Surplus of caloric content — alimentary adiposity of 1-4 degrees.

Ø Hypervitaminoses A and D.

Ø Syndrome of excess of proteins, fat acids.

Ø Excess of mineral substances — fluorosis, selenosis, molybdenum gout.

 

Principles of Rational Nutrition and Methods of Control of Their Observance

They were developed by academician A. A. Pokrovsky in the USSR and are now recommended by WHO for estimation of adequacy of individual nutrition and nutrition of population of different countries. It is a scientific basis of hygiene of nutrition.

 

1. Conformity of caloric content of nutrition to the daily energy consumption.

This is the main principle of rational nutrition with which the analysis of nutrition begins.

Methods of Control

Caloric content of nutrition is estimated by:

· a table-calculation method (taking into account a dietary intake and according to tables of food value of products) with the help of calorimetric coefficients.

Calorimetric coefficients of nutrients:

1g proteins and carbohydrates = 4 Kcal,

1g fats = 9 Kcal.

Proteins give 14 %, fats — 30 %, carbohydrates — 56 % of daily calories.

· a laboratory method — burning of 100 g of food product in a calorimetric bomb.

Daily Energy Consumption

It is composed of the basic exchange + energy consumption for work + 10 % of the basic exchange for food digestion.

The basic exchange is calculated by tables in accordance with sex, age, height and weight.

Ways of estimation of energy consumption for work:

· Table-chronometric method (by time of performing any activity),

· Direct calorimetry (in the calorimetric chamber)

· Indirect calorimetry (by respiratory coefficient = O2/CO2)

 

2. Balanced nutrition.

The diet should contain all necessary nutrients: proteins, fats, carbohydrates, vitamins, mineral substances in an optimum ratio. It provides a better absorption and full-value use of food substances. Examples of balance:

Ratio of proteins, fats, carbohydrates (P:F:C) = 1:1:4 (an adult person), 1:1:5 (hard physical work), 1:0.8:3 (elderly people), 1:1:3 (children).

Ratio of proteins: of animal origin — 60 %, of vegetative origin — 40 %,

Ratio of fats: of animal origin — 70-80 %, of vegetable origin — 20-30 %

Ratio of carbohydrates: digestible — 10-15 %, indigestible — 85-90 %.

Ratio Са:P = 1:1.5, etc.

Methods of control: а) table-calculation, b) laboratory (proteins in foodstuffs are determined by Keildal, fats — by Sokslet method).

 

3. Optimal diet regimen.

The food should be taken every 4-5 hours (time of evacuation function of the stomach), i.e. 4-5 times a day. Food intake less than in 2 hours is not optimal because gastric secretion is suppressed. Nutrition less than 3-4 times a day is harmful, because of great appetite a person eats plenty of food that leads to hypercholesterolemia, hyperlipemia, adiposity, etc.

Taking food at one and the same time (±30 minutes) is of great importance as a conditioned reflex of digestion is formed. The recommended distribution of daily caloric content by meals is as follows:

Breakfast — 25-27 %, lunch — 10-15 %, dinner 35-45 %, supper 10-20 %.

Methods of control include filling in a questionnaire about a diet and evaluation of caloric content of each meal.

 

4. Good organoleptic properties of food, its high digestibility, favorable conditions of taking food.

This is necessary for maintenance of normal conditioned-reflectory activity of digestion (Acad. I. P. Pavlov).

 

5. Safety of food in chemical and epidemiological respect.

It means absence in foodstuffs of chemical substances or microbes in amounts higher than allowable levels which may cause food poisonings. Now it is a very important principle in view of global pollution of biosphere by heavy metals, radionuclides, pesticides, etc. Ways of control are chemical and bacteriological analyses of foods and comparison of the results with food stan dards.

Theories and Concepts of Nutrition

In ancient times the hemopoietic antique theory of nutrition by Aristotle-Galen existed, according to which blood is food transformed in intestines.