Fundamentals of food technology study manual

2.2. Technology of milk processing and production of dairy products 
Milk is a food product necessary for human health. According to nutritionists 
and pediatricians, dairy products are extremely important for children's mental and 
physical development. About 95 percent of the milk used for food is cow's milk. 
The usefulness of milk is determined by the presence of the most beneficial 
biologically active substances in its composition. However, the composition of 
milk varies. It depends on the state of health of cattle, breed and individual 
characteristics, age, conditions of preservation and external environment, methods 
of milking. The main substances included in milk and their average amount are as 
follows: total protein 3-3.3%; main protein (casein) 2-2.8%; the amount of whey 
proteins is 0.4-0.5%; non-protein nitrogenous substances 0.17-0.38%; lactose 4.4-
5.0%; the amount of all dry matter in milk is 11.5-13%; 
In addition to being an excellent food product for humans, milk also serves as 
a good environment for the growth of various microorganisms, including disease-
causing microorganisms. That is why it is necessary to strictly follow the rules of 
sanitation and hygiene in the process of obtaining milk. In some cases, primary 
processing and cooking is carried out on farms. 
Dairy enterprises do not accept milk that has a spoiled taste, is sour, smells of 
onions or garlic. Such milk is not suitable for the production of high-quality 
products. Purchase prices set for milk are classified according to its quality. That is 
why agricultural farms benefit from improving the quality of milk. 
Milk processing enterprises are conditionally divided into the following 
according to the type of their main products: enterprises producing products that 
can be canned, dried and frozen; enterprises producing children's food products; 
butter and glaze production enterprises; ice cream production enterprises. 
Regardless of the type of enterprise, before receiving milk tankers, the main 
parameters such as taste, color, smell, acidity, fat and protein content, as well as 
the degree of contamination with bacteria are determined in the laboratory. In this 
case, the fat content of the milk should not be less than 3.2% and the acidity should 
not be higher than 200T (Turner). Based on these indicators, the milk is returned to 

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the owner if it does not meet the requirements of GOST. The laboratory staff 
monitors the work of all workshops in the enterprise and the quality of the final 
product. In particular, the cleanliness of washing equipment and milk transfer pipes 
is strictly monitored. In a special department of the laboratory, pure cultures are 
selected and drops are prepared for products produced by adding lactic acid 
bacteria. 
Received milk is cleaned of mechanical impurities and pasteurized before 
storage or further processing. Thermal pasteurization can be performed in three 
different conditions: 1) continuous pasteurization - 30 minutes, 63-650 С; 2) short-
term pasteurization - 15 minutes, 72-740 С; 3) momentary pasteurization - 82-850 
С. In addition, methods such as electropasteurization, ultrasonic pasteurization, 
and ultraviolet pasteurization are also recommended. Pasteurized milk can be 
delivered to the consumer as a finished product like sterilized milk. 
Storage conditions for pasteurized milk are selected depending on its storage 
period. Storage of milk and milk products is mainly carried out in a refrigerated 
state. Cooling milk prevents negative microbiological processes that affect its 
quality. At a temperature of 4-60 С, milk can be stored for up to two days. Chilled 
milk is stored in cooling tanks of 2-10 thousand liters. Tanks are cooled using 
chilled or salt water (brine). 
Fermented milk products or products made by congealing milk can include 
prostokvasha, (yoghurt, ryazhenka, yogurt, etc.), kefir, kimiz, sour cream, and 
cottage cheese. Their digestion in the body is much easier than milk. Sour cream is 
made from liquid cream, unlike other products made from cooked milk. For this 
reason, it is characterized by a large amount of oil in its composition. The common 
feature of products made by freezing milk is that during freezing, the curdling 
process occurs and lactic acid is formed. Such a process is used in the production 
of prostoquashes. However, if ethyl alcohol and carbon dioxide are produced at the 
same time as lactic acid during fermentation, products or drinks such as kimiz or 
kefir are produced. Both of these groups of products are made only from 
pasteurized milk. For the production of these products, the natural microflora of 
milk, specially selected lactic acid bacteria, is replaced by microflora of milk. As a 
result of the growth of these microorganisms, the desired product is produced. 
Therefore, a special dropper is used for each type of freezing product. To prepare 
kefir, which differs from Prostokvasha, only kefir fungus is used, which consists of 
a symbiosis of microbes. Special laboratories are engaged in the selection and 
testing of pure cultures for the preparation of drops. The quality of the drop and the 
optimal environment and conditions for the cooling process determine the quality 
of the finished product. For the production of these products, the natural microflora 
of milk, specially selected lactic acid bacteria, is replaced by microflora of milk. 
As a result of the growth of these microorganisms, the desired product is produced. 
Therefore, a special dropper is used for each type of freezing product. To prepare 
kefir, which differs from Prostokvasha, only kefir fungus is used, which consists of 
a symbiosis of microbes. Special laboratories are engaged in the selection and 
testing of pure cultures for the preparation of drops. The quality of the drop and the 
optimal environment and conditions for the cooling process determine the quality 

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of the finished product. For the production of these products, the natural microflora 
of milk, specially selected lactic acid bacteria, is replaced by microflora of milk. 
As a result of the growth of these microorganisms, the desired product is produced. 
Therefore, a special dropper is used for each type of freezing product. To prepare 
kefir, which differs from Prostokvasha, only kefir fungus is used, which consists of 
a symbiosis of microbes. Special laboratories are engaged in the selection and 
testing of pure cultures for the preparation of drops. The quality of the drop and the 
optimal environment and conditions for the cooling process determine the quality 
of the finished product. As a result of the growth of these microorganisms, the 
desired product is produced. Therefore, a special dropper is used for each type of 
freezing product. To prepare kefir, which differs from Prostokvasha, only kefir 
fungus is used, which consists of a symbiosis of microbes. Special laboratories are 
engaged in the selection and testing of pure cultures for the preparation of drops. 
The quality of the drop and the optimal environment and conditions for the cooling 
process determine the quality of the finished product. As a result of the growth of 
these microorganisms, the desired product is produced. Therefore, a special 
dropper is used for each type of freezing product. To prepare kefir, which differs 
from Prostokvasha, only kefir fungus is used, which consists of a symbiosis of 
microbes. Special laboratories are engaged in the selection and testing of pure 
cultures for the preparation of drops. The quality of the drop and the optimal 
environment and conditions for the cooling process determine the quality of the 
finished product. Special laboratories are engaged in the selection and testing of 
pure cultures for the preparation of drops. The quality of the drop and the optimal 
environment and conditions for the cooling process determine the quality of the 
finished product. Special laboratories are engaged in the selection and testing of 
pure cultures for the preparation of drops. The quality of the drop and the optimal 
environment and conditions for the cooling process determine the quality of the 
finished product. 
The basics of Prostokvasha preparation are as follows: Short-term pasteurized 
milk is cooled to a temperature of 38-420 С for freezing. Drops prepared from 
special microorganisms (Str. lactis - lactic acid streptococci) are slowly added to 
the milk and thoroughly mixed so that the milk itself does not foam. In order for 
the drops to spread evenly, the cooled milk is packed in various containers (cups, 
glasses, bottles) and closed. The dishes are held in the thermocamera at the exact 
temperature specified above. If the acidity of the heated product is 750T, the 
thickness is sufficient and uniform, and the whey is not separated, the prostokvasha 
is immediately cooled to a temperature of 6-80 С. When cooling, the milk protein 
swells again, and due to the reduction of free moisture, the density of prostokvasha 
increases. Prostokvasha storage conditions should not exceed 8-100 С. Sugar and 
other additives are added to milk before freezing to make sweet or flavored 
prostokvasha. There are ways to increase the nutritional value of prostokvasha by 
increasing the amount of milk solids (18-20%). 
For the production of acidophilic fermented milk products, special bacilli 
isolated from the intestine of young children (Bact.acidophilum - acidophilic 
bacilli) are used. In this, pasteurized milk is cooled to a temperature of 40-420 С. 

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The acidity of the finished product is 90-140 0T, the cooling temperature is 3-50 С. 
Acidophilic fermented milk products are produced in the form of acidophilic milk, 
acidophilic-fermented milk, acidophilin, acidophilic paste. Since these products 
contain a lot of different beneficial bacteria, they are widely used as dietary 
products for the treatment of dysbacteriosis. 
Cottage cheese is produced by curdling pasteurized milk with the help of 
mesophilic lactic acid bacteria. In this case, pasteurized milk is cooled to a 
temperature of 30-320 С, and a drop of 5% lactic acid bacteria is added while 
stirring. When the acidity of the mixture reaches 32-35 0T, a 40% calcium chloride 
solution is added to each ton of milk at the rate of 1,254 liters, mixed well, and a 
drop of pepsin prepared in serum with an acidity of 60-70 0T is added. Curd 
sediment should be dense and acidity should be 58-60 0T. If the milk is not cooled 
sufficiently and properly, a hard, rubbery curd is produced, which is difficult to 
separate from the whey. If the milk cools down too much, the curd will be sour, 
crumbly and less runny. Therefore, freezing after adding drops should not last 
more than 4.5-5 hours. The whey of the finished curd is shaken, then pressed and 
cooled to a temperature of 80 С. Cottage cheese should be stored at a temperature 
of 3-4 0 С. 
Sour cream is a product obtained by congealing cream with the help of special 
streptococci. Acidity of sour cream is 65-90 0T for high grade, fat content is 
mostly 30%. For this, the fat content of the cream should be 31.6%. 
For making sour cream, pasteurized cream is cooled to 18 0 С in summer and 
22 0 С in winter, and 3-5% drops are added. It is stirred every hour for three hours. 
The acidity of the mixture is left alone until it reaches 65-90 0T. Then the cooled 
cream is thoroughly mixed and left for a day at a temperature of 2-8 0 С to mature 
to the level of sour cream. Ready-made sour cream is packed. 
Morojenoe is a pasteurized and frozen mixture of milk, sugar, stabilizers, 
flavors and aromas. Ice creams are divided into filling (2600 kcal/kg), cream (2000 
kcal/kg), milk (1350 kcal/kg) and fruit (1300 kcal/kg) bases. The difference 
between them is the amount of fat in the filling, 12-15% in filling, 8-10% in cream, 
2.8-3.5% in milk and 0% in fruit ice cream. The name of the ice cream comes from 
the name of its base and addition. For example, cream-chocolate, milk-chocolate, 
fruit-filler, etc. 
The main raw materials of ice cream are natural and skimmed milk with an 
acidity not higher than 22 0T, cream with an acidity not higher than 200 T, canned 
milk and butter. And for fruit ice creams, fruit and fruit juices, syrups and fruit 
essences. Auxiliary additives are divided into sugars, flavoring agents, flavoring 
agents and stabilizers. Sugars (sugar, honey, molasses, glucose) not only give ice 
cream a sweet taste, but also create a soft structure and lower the freezing 
temperature. Gelatin, agar, starch, sodium caseinate, sodium alginate, and eggs are 
added as ice cream stabilizers, which are hydrophilic and have high swelling 
properties, improve the structure of ice cream, and reduce the size of ice crystals. 
The main processes of ice cream production are as follows: preparation of raw 
materials and additives and mixing, pasteurization of the mixture, homogenization, 
cooling and ripening, freezing, cooling of ice cream. The ice cream mixture 

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prepared from the raw materials according to the recipe is pasteurized for 30 
minutes at a temperature of 68-700 С. Pasteurized mixture is filtered while hot, 
100-150 atm. homogenized by pressure. In this case, the viscosity of the mixture 
increases up to 5-15 times, and its foaming properties increase. The homogenized 
ice cream base is cooled to a temperature of 2-4 0 С, kept at this temperature for up 
to 4 hours and matured. In this case, the stabilizers absorb moisture, and the ice 
cream base becomes a soft gel. The main process in the production of ice cream is 
freezing or milling. During the process of freezing and intensive mixing, air is 
introduced into the ice cream mass and foaming is carried out. The more water that 
is frozen during the freezing process, the less time it takes to cool the ice cream 
and the better the quality of the ice cream. Keeping ice cream at the lowest 
possible temperature (-15-25 0 С) before it is put on sale increases its quality even 
more. 
Butter or milk fat is a high-calorie (7800 cal/kg) easily digestible food 
product. It contains 52% to 92% milk fat, 1% to 35% water and 1% to 13% non-fat 
substances (lactose, proteins, etc.) and vitamins. However, butters may differ from 
each other in terms of taste, aroma, and other product characteristics. This 
difference is caused by the raw materials, methods of their production, and added 
flavorings and aromas. Different butters can be divided into three main groups: 
1. Butter made from milk cream (slivochnoye) 
2. Butter made from whey cream. 
3. Melted or mechanically processed oils. 
In the traditional way, the production of butter from milk cream is carried out 
as follows: the cream is separated from the milk, the cream is pasteurized and 
cooled and strained. The oil is separated from the finished cream by beating 
(chasing). Separated butter is washed with water and salt is added to some types. 
The skimmed milk and butter from which the cream is extracted, the residue after 
separation is given to the seeds for reuse. Ready butter is placed in cardboard 
boxes and stored in cold rooms. 
In addition to the general requirements, there are certain requirements for the 
fat content of the milk used for making butter. At the same time as the fat content 
of milk is high, the larger the size of the oil particles, the easier it is for the butter 
to escape from the cream, and the more it comes out. 
Cheese is a food product rich in protein, fat, calcium, phosphates and 
vitamins. It is very filling and easy to digest. 
The quality of the produced cheese is highly dependent on the characteristics 
of the milk used for it. If milk fat and protein (casein) determine the amount of 
cheese, their ratio determines the fat content of cheese. Various salts in milk ensure 
that the protein structure is in a certain state. Different microorganisms in milk can 
have different effects on the milk fermentation process. Therefore, the quality of 
milk is the most important factor that can affect the quality of cheese production. 
In the production of cheese, the ability of milk to curdle under the influence 
of special enzymes and form clots is very important. Prepared milk is short-term 
pasteurized at a temperature of 72 0 С in order to remove bacteria that can produce 
gas as a result of fermentation. Milk that coagulates too slowly and forms a loose 

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clot, and milk that coagulates too quickly and forms a dense clot, are not suitable. 
Milk is divided into 3 groups according to these characteristics: Group 1 milk 
spoils within 15 minutes; Group 2 milk for 16-40 minutes; Group 3 milk does not 
spoil after 40 minutes. Group 2 milks are considered excellent for cheese 
production. In addition, fresh milk is not suitable for making cheese. After cooling 
the milk to a temperature of 12-130 С, If it is kept for 10-12 hours, its acidity 
reaches 20-22 0T. By mixing such milk with fresh milk, milk with the required 
acidity is prepared according to the type of cheese. 
Because the special enzymes used in cheese making contain lactic acid 
streptococci, the optimal temperature for freezing and coagulation of milk is 30-35 
0 С. After adding enzymes to milk, during the period of coagulation and 
sedimentation, the milk mass must be kept at rest. Because the clot formed from 
the fusion of caseins must be a solid precipitate. Only then, both the quality and 
color of the cheese will be at the required level. 
The degree of whey separation from the precipitated curd also depends on the 
type of cheese being produced. The rate of serum separation is inversely 
proportional to the oiliness of the clot and directly proportional to the amount of 
calcium in it. In the tub where the curd mass is located, the precipitate is cut from 
0.5 mm to 20 mm, depending on the type of cheese, with vertical and horizontal 
knives, and it is dried with a little heating and stirring. Sufficient drying of the 
cheese mass and maturity of the cheese kernels is determined by organoleptic and 
tactile inspection. When it is sufficiently ripe and sticky, it is given to molding and 
then pressing. During molding, the whey in the cheese is reduced, and the cheese 
mass is made into a dense monolithic. Cheeses with less whey are pressed harder, 
otherwise, it should be pressed more slowly. Pressed cheese is salted by placing it 
in 22-24% salt water or rubbing dry salt. As the acidity of water used many times 
increases, it is neutralized with mel or lime. Salted cheese is placed in the cellars 
for the final maturation process. The temperature should be 10-12 0 С and 
humidity 88-95%. Depending on the type of cheese, its ripening period can last 
from several days to several months. Ready cheese is stored in the refrigerator. 
Salted cheese is placed in the cellars for the final maturation process. The 
temperature should be 10-12 0 С and humidity 88-95%. Depending on the type of 
cheese, its ripening period can last from several days to several months. Ready 
cheese is stored in the refrigerator. Salted cheese is placed in the cellars for the 
final maturation process. The temperature should be 10-12 0 С and humidity 88-
95%. Depending on the type of cheese, its ripening period can last from several 
days to several months. Ready cheese is stored in the refrigerator.