Milk nutritional value. The nutritional value of milk, its importance in nutrition

The nutritional value of milk and products prepared on its basis determines its importance in children's and dietary nutrition. By including such foods in your diet, you will saturate the body with calcium and other valuable substances. Milk makes a person healthier and more beautiful.

What is nutritional value?

If you are interested in certain characteristics of products, you should know for sure what they mean. Thus, nutritional value is a complete list of properties that satisfy the physiological needs of the body. Most often, this concept means the content of proteins, fats and carbohydrates in every 100 grams of products.

It is also worth noting the importance of such an indicator as biological value. It characterizes the compliance of the amino acid needs of the human body. Speaking of energy value, it is worth noting that this is the number of calories that are released during the processing of the product by the body.

Milk: chemical composition and nutritional value

Milk is the first human food, which gives the body everything it needs from birth. Due to the rich chemical composition, it is possible to maintain the active vital activity of the body. So, milk contains the following substances:

• proteins;
• fats;
• milk sugar;
• mineral salts;
• water.

It should be noted that this is a basic set of components that cannot fully characterize milk. The chemical composition and nutritional value can vary greatly, depending on the origin of the product, as well as the way it is processed.

If we consider in more detail the proteins contained in milk, they are represented by albumin, globulin and casein. The latter is involved in the formation of glycopolymacropeptide, which increases the absorption of other components. All proteins are characterized by easy absorption and contain all the amino acids necessary for the body.

Fats in milk are contained in the form of tiny particles. It is they who form everyone's favorite cream. Milk fat is 96% absorbed by the body, due to its high dispersion. Its content in the product depends on the season (in summer this figure decreases), as well as the quality of animal care.

Considering such an indicator as the nutritional, energy value of milk, one cannot but say about the carbohydrate component. It is represented by lactose. It is the presence of this component that determines the possibility of preparing fermented milk products.

The nutritional value of milk is determined by the high content of vitamins. The main ones are A and B. Ascorbic acid, nicotinic acid, riboflavin and thiamine are present in a small amount. The highest concentration of vitamins in milk is observed in the summer. Also, this indicator can be affected by the method of processing and storage conditions.

More about vitamins

As already mentioned, the nutritional value of milk and dairy products is largely due to the increased content of vitamins in them. So, if we take a closer look at the chemical composition, we can note the presence of the following useful components in it:

Vitamin	Benefit	Where is contained
IN 1	It takes part in metabolism, normalizes the functioning of the nervous system and heart muscle, improves the condition of the skin and hair.
AT 2	Takes part in protein and carbohydrate metabolism.	Milk, dairy products, cheeses, whey and cream
AT 3	Regulates fat metabolism, and also activates the synthesis of amino acids.
AT 6	Promotes lipid and protein metabolism.	Milk
AT 12	Strengthens the immune system, reduces the risk of tumor formation, increases the body's resistance to radiation.	Milk and cheeses
A	Improves the functional state of tissues.	Milk and dairy products

Different types of milk

The nutritional value of milk is largely determined by its origin. So, deer is considered the most nutritious. The concentration of proteins and fats reaches, respectively, 11% and 20%. As for the vitamin component, it is three times more saturated than in the case of cow's milk.

The nutritional value of milk is largely determined by the nature of the proteins that it contains. So, most farm animals (including cows and goats) give casein milk. And, for example, mare and donkey is albumin. Since it is most similar in composition to mother's milk, such milk is an ideal substitute for breastfeeding. Albumin particles are several times smaller than casein, and therefore we can talk about its good digestibility.

Whole milk

Despite the fact that milk is one of the most common products that has been known since childhood, not everyone thinks that there are several types that are characterized by certain indicators. So, for starters, you should pay attention to whole milk. The nutritional value, in this case, will be the highest, because the product has not been subjected to any processing. An exception may be the straining process, which is carried out immediately after milking.

Whole milk contains the highest amount of vitamins and minerals. There is also a high concentration of calcium, which is almost completely absorbed by the body. This product is credited with strengthening the immune system, normalizing the functioning of the nervous system, eliminating heartburn, accelerating metabolism.

However, there are a number of skeptical claims about whole milk. Given its high fat content, it is not suitable for feeding children. And in adulthood, not everyone tolerates this product well. So, according to the latest data, one sixth of the world's population suffers from lactose intolerance. Whole milk is an allergen, and can also cause dangerous infections.

Skimmed milk

The desire for harmony makes people buy products marked "0% fat". This trend has also affected milk. The amount of fat in it does not exceed 0.1%. In fact, this is the so-called reverse, which is obtained by separating cream from milk. It should be interesting to buyers that most of this milk is not sent to store shelves, but back to farms to feed animals.

Do not place high hopes on a product such as skimmed milk. Its nutritional value is negligible. Carbohydrates and proteins, respectively, 5% and 3%. Calorie content is characterized by an indicator of 35 kcal. At the same time, such milk is characterized by a rich vitamin and mineral composition. Nevertheless, doctors do not recommend using it on an ongoing basis.

It is worth paying attention to the manufacturing process. The nutritional value of powdered, skimmed milk is significantly reduced during processing. When the fat component is removed, vitamins A and D are almost completely removed from the product. Thus, the proteins and calcium that remain in the milk are not absorbed by the body. With the frequent use of skimmed and powdered milk, the body's own resources are depleted.

Powdered milk: nutritional value

In a big city, it is not always possible to find a natural product. In addition, people tend to give known substances a more convenient form, such as powder. Powdered milk is a good example. The nutritional value of this product is the same as that of the original. But for this you need to prepare the so-called reconstituted milk. To do this, the powder is diluted in water (1: 7). At the same time, it is quite possible to prepare homemade kefir, cottage cheese and other healthy products from such milk.

The nutritional and biological value of milk is preserved thanks to a special manufacturing technology. Fast drying is carried out, and the temperature does not exceed 40 degrees. Thus, all useful substances are preserved. And due to the reduced moisture content (no more than 6%), long-term storage of the product is ensured.

Nutritional value of condensed milk

It is worth admitting that few people are interested in such a question as nutritional value. For most people, this is a favorite delicacy. Nevertheless, condensed milk is not only tasty, but also a very useful product. To begin with, it is worth noting the high protein content in this product. Its concentration can reach 35%.

In fact, condensed milk is evaporated cow's milk. The nutritional value of the final product is slightly lower, but in general it is no less useful. Condensed milk is completely absorbed by the body, saturating it with calcium and phosphorus. Thus, by regularly consuming this product, you can strengthen the health of bones, eyes and enhance mental activity.

However, condensed milk should not be abused. The fact is that it contains a significant amount of sugar, which leads to a high calorie content (328 kcal) and a significant carbohydrate component (55.5 g). A large amount of the product contributes to the development of obesity, diabetes and caries.

Dairy products

The composition and nutritional value of milk make this product one of the most popular. However, in its pure form, few people love it. Most people prefer dairy products. They not only retain the benefits of milk, but also have a beneficial effect on the digestive system. So, you should especially pay attention to the following products:

• Kefir is made from pasteurized milk. A special leaven is added to it, after which the fermentation process begins. The nutritional value of this product depends entirely on the quality of the milk. If a whole product is used, then the protein component accounts for almost 3%, the fat concentration is 3%, and carbohydrates 4%.
• prepared from a pasteurized product using bacterial cultures. It will contain approximately equal amounts of fat and carbohydrates (about 3%) and 10% carbohydrates. Given the low acidity of the product, it is actively used in artificial feeding of children.
• Belakt is also a fermented milk product produced using bacteria. It has a high content of enzymes. Another feature of the product is the presence in the composition of substances that, in their properties, resemble antibiotics.
• "Narine" is a fermented milk product that came to us from Armenia. There it is actively used for breastfeeding. Due to the special bacteria contained in the sourdough, the acidity index is quite low. And, getting into the body, "Narine" activates the production of a substance that suppresses pathogenic microbes. Proteins and fats in the product account for 3% and 4%, respectively, and carbohydrates - just over 6%.
• Koumiss is traditionally made from mare's milk. Nevertheless, recipes adapted for cow's are known. In milk, starter is added, which contains bacteria and yeast. The nutritional value largely depends on the quality of the base and the degree of maturity. It can contain up to 3% protein, up to 1% fat and 6% carbohydrates. The product is useful for digestion, and also has a tonic effect.
• Yogurt is not just a popular fermented milk product, but also a delicacy loved by everyone. In ancient times, it was prepared exclusively from To get yogurt, you need to add the so-called Bulgarian stick to the base. On average, the calorie content of the finished product is characterized by an indicator of 57 kcal. Proteins, fats and carbohydrates it contains, respectively, 4%, 2% and 6%. These figures may vary, depending on the type of milk and the method of processing. It is worth noting that only pure yogurt, which does not contain dyes and flavoring additives, has exceptional benefits.

Other popular products

Since ancient times, people have been interested in such a question as the nutritional value of milk. A great variety of dairy products are prepared on its basis. Nevertheless, there are a number of popular ones that are almost always present on the table, namely:

• Cottage cheese is one of the most valuable food products, which is characterized by a high protein content (about 14%). Its preparation is based on processes. Curd is characterized by high acidity. But this indicator decreases with an increase in the level of fat content of the product.
• The process of making cheese is based on the precipitation of casein. Depending on how the milk is processed, the product can be hard, soft, brine or melted. The protein component can reach 30% (as well as fat).
• Sour cream is a product made from pasteurized cream. It is quite fatty (this figure can reach 40%).

Milk quality

The high nutritional value of milk proteins determines the popularity of this product. Nevertheless, only what is of high quality is useful for the body. The characteristics of milk largely depend on how the processing was carried out.

The milk that entered the plant is first of all checked by organoleptic index. If it turned out to be in accordance with the standards, it is carefully filtered to remove impurities. Next, the fat content is normalized by adding skim milk or cream.

The most important are the stages of pasteurization and sterilization. These processes are necessary for the destruction of pathogens, as well as a number of enzymes. Thus, it is possible to obtain a safe product, which is characterized by long-term storage.

Pasteurization is carried out by prolonged heating. As a result, milk changes its natural taste. It is also worth noting the decrease in the concentration of calcium in the product.

Is milk dangerous for humans?

The nutritional and biological value of milk makes this product one of the most useful. Nevertheless, it is worth mentioning the danger that it carries. Milk can serve as a source of dangerous infectious diseases. In this case, viruses can get into the product from the animal and during processing.

Viruses can be found not only in milk, but also in products prepared on its basis. This increases the incubation period of the bacteria. So, the most dangerous diseases transmitted through milk are the following:

• Foot and mouth disease is a viral disease that affects the mucous membranes and respiratory tract. It appears in the form of blisters and ulcers. The virus of this disease is resistant to heat. To get rid of it, you need to boil the milk for at least 5 minutes.
• Brucellosis is a disease that affects almost all body systems. Its danger lies in the fact that at the initial stage it is almost asymptomatic. Milk from animals infected with brucellosis is subjected to prolonged boiling followed by pasteurization.
• Tuberculosis - affects mainly the respiratory system. If such an infection is found in an animal, then milk is strictly forbidden to be eaten.
• Other dangerous infections are anthrax, rabies, hepatitis, plague, and others. Animals with such diseases are subject to destruction with the obligatory presence of a sanitary doctor.

Conclusion

From the very first days of a person's life, it is milk that supplies the body with all the necessary nutrients and vitamins. Thus, the benefits of this product are undeniable. To maintain bones, digestive, nervous and other body systems in optimal condition, milk simply must be present in the diet. It is important to choose a quality product, and treat it whole or fat-free with caution.

At the moment, there is a wide range of dairy products on the market, which are also characterized by high nutritional value. Among them, you can often find many copies marked "Farm" or "Rustic". Contrary to fashion trends, such products should be treated with extreme caution, because milk that has not been subjected to heat treatment and pasteurization may contain viruses that are dangerous to humans.

Introduction

Relevance: An important place in the human diet is occupied by milk and dairy products. Milk contains all the nutrients needed by the human body without exception. One of the most distinctive and important properties of milk as a food product is its high biological value and digestibility due to the presence of complete proteins, milk fat, minerals, trace elements and vitamins.

The digestibility of milk and dairy products ranges from 95 to 98%. Milk also aids in the absorption of other foods. Of particular importance for the body are sour-milk products, which have a high dietary and medicinal value.

Along with cow's milk, milk of other animals is used for food: sheep, goats, deer, mares, camels, buffaloes, etc.

Sheep's milk is more than 1.5 times richer in fat and protein than cow's milk. It is used for the production of feta cheese and other types of pickled cheeses.

Goat's milk is used in a mixture with sheep's milk in the production of feta cheese and cheese. Goat milk has more vitamin C and minerals than cow milk.

Mare's milk is a white liquid with a bluish tint. It differs from cow's sweet taste due to the increased content of lactose, contains less fat, salts and proteins. It is used to make koumiss.

Purpose, objectives of the course work- studying the features of the technology for obtaining benign milk.

Nutritional value, composition and properties of cow's milk

Nutritional value of milk

Cow's milk has a high nutritional value, which is due to the optimal content of proteins, fats, carbohydrates, mineral salts and vitamins in it, and the ratio and form in which the components are present in milk contribute to their good digestibility and assimilation. Currently, over 200 different components are known in milk. The main components include water, protein, fat, lactose and minerals (see Table 2).

Milk also contains vitamins, enzymes, hormones, etc. Foreign substances may contain antibiotics, pesticides, detergents, toxic elements, radionuclides, aflatoxins, etc.

The chemical composition of milk, the degree of dispersion of its components determine the chemical and physical properties of milk. The most important properties for milk processing processes are given in Table 5.

Milk and dairy products are characterized energy value, which complements the nutritional value of the product. It can be calculated using the following formula:

E \u003d (37, 7F + 16.7B + 15.9L) * 1,

where E - energy value, kJ; W, B, L - respectively, the mass fraction of the content of fat, protein and lactose in the raw material or product,%; 37.7, 16.7 and 15.9 are coefficients.

Table 5. Chemical and physical properties of cow's milk

At a temperature of 20 °C.

Everyone knows the high biological value of such a food product as milk. Especially useful milk for children.

Milk is among the food champions in terms of the content of complete proteins, fats, phosphatides, mineral salts and fat-soluble vitamins, and in total about a hundred substances were found in milk, which are very important from a biological point of view.

The chemical composition of milk

In figures, the chemical composition of milk, depending on the breed, feed, season, age of cows, lactation period and product processing technology, may look something like this:

• water 87.8%,
• fat 3.4%,
• proteins 3.5%,
• milk sugar 4.6%,
• mineral salts 0.75%.

It is important that milk proteins are an easy product for digestive enzymes, and the uniqueness casein is the ability to form a glycopolymacropeptide during digestion, which increases the digestibility of other food ingredients.

The chemical composition of milk In addition to casein, it contains complete proteins globulin and albumin containing all the amino acids that are necessary for the body. Casein in milk is associated with calcium, and when milk souring, calcium undergoes splitting and casein coagulates and precipitates.

When milk is defended, the smallest fat globules in it float up, forming a layer of delicious and healthy cream. The low (28-36 0 C) melting point of this product, as well as its high dispersity, makes almost complete digestibility of milk fat possible.

Nutritional value of milk

Milk carbohydrates, this is milk sugar - lactose, it is not as sweet as vegetable sugar, but it is not inferior to it in nutritional value. When boiled, milk sugar caramelizes, which causes the milk to acquire a brownish color and a special aroma and taste. Under the influence of lactic acid bacteria, milk sugar becomes lactic acid, and casein curdles. As a result, curdled milk, sour cream, kefir, cottage cheese are obtained - such tasty, nutritious and healthy products. Milk contains calcium, phosphorus, potassium, iron, sodium and sulfur, and in an easily digestible form, and this is very important for baby food, when milk is the main product in the children's menu. Milk also contains trace elements copper, zinc, fluorine, iodine, manganese. Because of its chemical composition, milk has important nutritional value for the human body.

The main vitamin richness and nutritional value of milk is vitamins A and D, but besides them there are ascorbic acid, riboflavin, thiamine and nicotinic acid.

Milk enzymes

In addition, milk also contains a number of enzymes, of which it should be distinguished:

• peroxidase,
• amylase,
• phosphatase
• reductase,
• catalase
• lipase.

According to GOST 13277-67, fresh high-quality milk should be a homogeneous liquid product, white in color with a slightly yellowish tinge, have a pleasant taste and smell. Apart from possible deviations in the quality of this product, caused by unacceptable changes in the composition, for example, the presence of various harmful microorganisms, its color and smell can largely depend on the feed and storage conditions.

The benefits and harms of fresh milk

A foreign smell can occur in milk when it is stored next to substances that are characterized by a pungent smell - fish, tobacco, oil products, in rotten wooden cellars.

Freshly milked milk is far from a sterile product, since there is always a certain amount of microbes in the cavity of the mammary glands of the udder. These are mainly micrococci, but there are also lactic acid bacteria.

In addition, milk is a breeding ground for microorganisms that enter it during the milking process and later. In milk, these microorganisms multiply rapidly.

Along with such microflora, pathogenic microorganisms, such as causative agents of intestinal infections, can also be found in milk.

Therefore, according to existing sanitary rules, milk is allowed for use only after neutralization.

Basically, for this, the pasteurization method is used at a temperature of 70 0 C for half an hour, or heating at least 90 0 C for a few seconds.

Milk is a product of high biological value. Of the constituent parts of milk, of particular importance is:

A protein that is complete in terms of amino acid composition and has a high digestibility.

Milk fat contains biologically active fatty acids and is a good source of vitamins A and D.

Minerals in milk are represented by calcium, phosphorus, which are found in it in the form of organic salts that are easily absorbed by the body.

The high biological value of milk and dairy products makes them absolutely indispensable in the nutrition of children, the elderly and sick people.

Milk is a perishable product, which is a good breeding ground for the development of pathogens of various diseases.

Chemical composition and nutritional value of cow's milk

The chemical composition of milk depends on

animal breeds,

lactation period,

The nature of the feed

Milking method.

The chemical composition of milk: proteins - 3.2%, fats - 3.4%, lactose - 4.6%, mineral salts - 0.75%, water - 87-89%, dry residue - 11 - 17%.

Milk proteins have a high biological value. Their digestibility is 96.0%. Essential amino acids are contained in sufficient quantities and optimal ratios. Milk proteins include: casein, milk albumin, milk globulin, fat globule shell proteins.

Casein accounts for 81% of all milk protein. Casein belongs to the group of phosphoproteins and is a mixture of its three forms - a, p and y, which differ in the content of phosphorus, calcium, and sulfur.

Milk albumin has a high content of sulfur-containing amino acids. The content of albumin in milk is 0.4%. Milk albumin contains a lot of tryptophan. Milk globulins are identical to blood plasma proteins and determine the immune properties of milk. Milk globulins make up 0.15%, immune globulins - 0.05%. The protein of the shells of fat globules is a lecithin-protein compound.

milk fat in milk it is in the form of the smallest fatty globules and is represented by 20 fatty acids, mainly low molecular weight - butyric, caproic, caprylic, etc. There are few polyunsaturated fatty acids in milk, in comparison with vegetable oil. Light, oxygen, high temperature cause salting and rancidity of milk fat. Milk contains phosphatides - lecithin and cephalin. Of the sterols, milk contains cholesterol, ergosterol.

carbohydrates in milk are lactose, which, when hydrolyzed, breaks down into glucose and galactose. Lactose tastes less sweet (5 times) than beet sugar. Caramelization of lactose occurs at 170 - 180°C.

Minerals. Milk contains calcium, phosphorus, potassium, sodium in the form of easily digestible organic salts.

It should be noted the high content of calcium salts and its good ratio with phosphorus (1:0.8).

Of the trace elements in milk contains: cobalt - 0.3 mg / l, copper - 0.08 mg / l, zinc - 0.5 mg / l, as well as aluminum, chromium, helium, tin, rubidium, titanium.

Vitamins. With milk, a person receives vitamins A and D, as well as some amounts of thiamine, riboflavin. The content of vitamin A in milk is subject to seasonal fluctuations. In fermented milk products, the content of thiamine and riboflavin increases by 20-30% due to their synthesis by lactic acid microflora.

Milk contains many enzymes, included in its composition and produced by the microflora present in it. The level of individual enzymes is used to assess the degree of bacterial contamination of milk. For example, reductase is used to assess the degree of bacterial contamination of raw milk, phosphatase and peroxidase - to check the effectiveness of milk pasteurization.

Sanitary and epidemiological significance of milk. The role of milk in the occurrence of intestinal infections, food poisoning of a bacterial nature, measures for their prevention. Animal diseases transmitted through milk and sanitary assessment of milk obtained from farms unfavorable for tuberculosis, brucellosis, foot-and-mouth disease and other animal diseases.

Milk is an excellent nutrient medium for the development and reproduction of most types of microorganisms. Diseases transmitted through milk can be divided into two groups:

1) animal diseases

2) human diseases.

Animal diseases transmitted to humans through milk

The main diseases transmitted to humans through milk are

Tuberculosis,

Brucellosis,

coccal infections.

Brucellosis called Br. melitensis, Br. abortus bovis, Br. abortus suis.

Brucellosis affects cows, sheep, goats, deer; from pets cats and dogs.

2 forms of the disease:

Professional form on contact

Brucella are stable in the environment and are well preserved in milk and dairy products.

Sick animals are brought to separate brucellosis farms, the milk obtained from such animals is neutralized by heating, boiling for 5 minutes and used for household needs within the farm - for feeding calves.

The milk of animals that react positively to brucellosis, but without clinical signs of the disease, is allowed to be eaten after preliminary reliable pasteurization (30 min at 70 ° C); Pasteurization of such milk must be carried out on the farm. At dairies, milk coming from farms that are unfavorable for brucellosis is pasteurized again. Due to the special danger of Br. melitensis milking sheep with clinical signs of brucellosis is prohibited.

To prevent brucellosis, it is necessary once a year for the entire livestock to produce serological (Wright and Heddelson) or allergic (Burne) reactions to identify diseased livestock. This is part of the tasks of veterinary workers who monitor the condition of animals.

Tuberculosis It is caused by tubercle bacilli of three types: human, bovine, avian. The largest number of tubercle bacilli enters milk with udder tuberculosis of animals, as well as generalized and miliary forms of tuberculosis. Tuberculosis sticks remain viable in milk for 10 days, dairy products - 20 days, butter in the cold - 10 months, cheeses - 260-360 days. Milk from cows with tuberculosis is to be destroyed, and from cows that react positively, but do not have a clinical picture of tuberculosis, it is allowed to use it in nutrition after thorough pasteurization at a temperature of 85 ° C for 30 minutes.

Pasteurization must be carried out at the place of receipt of milk.

To prevent transmission through milk of tuberculosis from a person, it is necessary:

1) annual examination of employees of farms and dairy enterprises for tuberculosis;

2) removal from work of patients with an active form of tuberculosis;

anthrax caused by bacillus B. anthracis, which can be excreted in milk. The microbe itself is unstable and quickly dies in the environment, but is able to form stable spore forms. Milk from cows with anthrax must be destroyed under the supervision of a veterinarian. Preliminary neutralization of milk is carried out by adding 20% ​​chlorine-lime milk, boiling for 2-3 hours, adding 10% alkali and further heat treatment at a temperature of 60-70 ° C.

For the prevention of anthrax, active immunization of animals with a live attenuated Tsenkovsky vaccine or a live vaccine from an avirulent strain is used. The milk of vaccinated animals with the Tsenkovsky vaccine must be boiled for 5 minutes for 15 days. When using the STI vaccine, milk is used without restrictions; when the animal's temperature rises, the milk must be boiled.

Q fever, or pneumorickettsiosis, is caused by Burnet's rickettsia. Burnet's rickettsiae are excreted by animals in urine, milk, feces and fetal membranes. They are resistant to chemical and physical factors, they remain viable when heated for an hour at 90 ° C. In lactic acid products they remain viable for 30 days, butter and cheese - 90 days. Rickettsia Burnet is the most persistent of all other non-spore pathogens. Milk from animals with Q fever must be destroyed. Persons caring for sick animals must follow the instructions for caring for sick animals.

foot and mouth disease caused by a virus. Contained in saliva, urine, feces, milk of sick animals. The consumption of raw milk from sick animals is the cause of human disease. In the environment, the foot and mouth disease virus is stable, remains viable for 2 weeks, in feed - 4 months. It is very sensitive to the effects of physical and chemical factors. At 80-100 °C it dies instantly, it also dies quickly at pH 6.0-6.5. Quarantine is imposed on dysfunctional farms for foot and mouth disease and the export of milk is prohibited. Milk from sick animals must be boiled for 5 minutes. Such milk does not contain the virus and can be used on the farm. The ban on the export of milk is associated with the risk of the spread of foot-and-mouth disease to nearby areas. In some cases, when boiled milk and cream cannot be used on the farm, delivery to factories may be allowed under strict veterinary and sanitary supervision over the processing of exported containers.

Mastitis. Milk-borne food poisoning is mainly due to diseases of staphylococcal etiology. The main cause of staphylococci entering milk is mastitis in dairy cattle. With mastitis, milk is salty in taste and has an alkaline reaction. In milk, physical and chemical parameters change. Enterotoxin, which is formed in milk, can withstand heating up to 120 ° C, is preserved in pasteurized milk, products that have undergone heat treatment.

Nutritional value - the main characteristic of a food product - the amount of nutrients contained in it (proteins, fats, etc.) and their ratio.

Raw materials for milk production are natural milk, skimmed milk, cream.

Natural milk is full fat milk without any additives. It does not enter the sale, as it has a non-standardized fat content and SOMO. It is used to produce various types of milk and dairy products.

Skimmed milk - skimmed part of milk obtained by separation and containing not more than 0.05% fat.

Cream - the fat portion of milk obtained by separation.

Milk is a biologically valuable food product, especially for children. It contains high-grade proteins, fats, phosphatides, fat-soluble vitamins, mineral salts. In total, about 100 biologically important substances have been found in milk.

The chemical composition of milk is as follows: proteins 3.5%, fats 3.4%, milk sugar 4.6%, mineral salts (ash) 0.75%, water 87.8%. The chemical composition of milk varies depending on the breed of animals, the season, the nature of the feed, the age of the animals, the lactation period, and the technology of milk processing.

Milk proteins are readily available for digestive enzymes, and casein has a unique property, forming a glycopolymacropeptide in the process of digestion, to have a regulatory effect on increasing the digestibility of other nutrients.

Milk proteins are represented by casein, albumin and globulin. They are complete and contain all the amino acids necessary for the body. Casein in milk is in the form of caseinogen in a bound state with calcium. When milk souring, calcium is split off from casein, which, coagulating, precipitates.

Milk fat in milk is in the form of tiny fat globules 0.1-10 microns in size. When milk is standing, fat globules rise up due to their low specific gravity, forming a layer of cream. Due to the low melting point (within 28-36°C) and high dispersion, milk fat is digested by 94-96%. As a rule, the fat content of milk in autumn, winter and spring is higher than in summer. It also increases towards the end of the lactation period. In this case, the conditions of keeping the animal and the nature of the feed are of great importance. With good care, the amount of fat in milk can reach 6-7%.

Carbohydrates in milk are in the form of milk sugar, lactose, which is less sweet in taste than vegetable sugar, but its nutritional value is not inferior to it. When boiled, milk sugar caramelizes, giving the milk a brownish color and a specific aroma and taste. Milk sugar is of great importance in the production of lactic acid products. Under the action of lactic acid bacteria, it turns into lactic acid; while curdling the casein. This process is observed in the production of sour cream, curdled milk, cottage cheese, kefir.

The composition of milk includes phosphorus, calcium, potassium, sodium, iron, sulfur. They are found in milk in an easily digestible form, which is especially important in early childhood, when milk is the staple food. Of the trace elements in milk contains zinc, copper, iodine, fluorine, manganese.

The main vitamins of milk are vitamins A and B, some amounts of ascorbic acid, thiamine, riboflavin, nicotinic acid. Their content is subject to significant fluctuations. In summer, when animals eat juicy green fodder, the content of vitamins in milk increases. In winter, due to the transition to dry food, the amount of vitamins in milk decreases. In the future, the content of vitamins depends on the conditions of storage, transportation and processing of milk.

Milk contains a number of enzymes. The main ones are: phosphatase, peroxidase, reductase, amylase, lipase and catalase.