Drinking milk is today one of the most common products. A wide range of these products is produced in the Russian Federation. Depending on the heat treatment method used, several different types of product are distinguished. Each of them has its own characteristics.
Varieties of processing
Drinking milk in Russia is processed by various thermal methods. Depending on this, the following product groups are distinguished:
- Pasteurized milk.
- Ghee.
- Sterilized.
- UVT - processed.
- UVT - treated sterilized.
The difference in the processing method also affects such characteristics of the product: taste, nutritional and biological value, shelf life.
However, the assortment of drinking milk does not end there. Depending on the amount of fat, solids and flavors in the final product, there are:
- Whole milk.
- Normalized.
- High fat content.
- Reconstituted (powder).
In a separate group, you can distinguish drinking milk with various additives: coffee, cocoa and other types.
A significant difference is present in the method of packaging and packaging in which this product is sold. Milk goes on sale in transport containers, in tanks, flasks, in small packaging.
One of the most important points is that GOST of drinking milk sets standards for organoleptic, sanitary and hygienic, physico-chemical indicators. Each type of product has its own standards developed and established. All manufactured products must comply with the regulatory documents in force at the time of their release.
GOST technical requirements, physico-chemical and organoleptic norms
According to the specifications of GOST 31450-2013, drinking milk must meet the following organoleptic requirements:
- Appearance of the goods. It is an opaque liquid. For milk with a fat content of more than 4.7%, a small sediment of fat is allowed. However, with stirring, it must necessarily disappear.
- The consistency of the product should be liquid, not viscous, slightly viscous. Lumps of fat, protein flakes and other particles are absolutely unacceptable.
- Drinking milk according to GOST 31450-2013 should have a smell and taste characteristic of this product. Only a slight aftertaste of boiling is allowed. If milk belongs to the group of baked or sterilized products, then the taste of boiling should be pronounced in it.
- As for the color, it should be white. For skim milk, a bluish tint is allowed, light cream for sterilized, and cream for melted.
Specifications GOST 31450-2013 drinking milk set the standard for its physico-chemical parameters, which we have designed for convenience in a table.
| Name of physical and chemical characteristics | Parameter value |
| Density, measured in kg / m 3 | From 1024 (for skim milk) to 1030 (for skim) |
| Mass fraction of protein in% (not less) | 3.0 |
The acidity parameter is measured in ° T (no more) | 21 for all products with a mass fraction of fat, except 4.7; 5.0; 5.5; 6.0; 6.5; 7.0; 7.2; 7.5; 8.0; 8.5; 9.0; 9.5. For this fat content, the acidity index is 20. |
Permissible mass fraction of non-fat dry milk residue in% (not less) | 8.2 |
| For a pasteurized, melted or ultra-pasteurized product without aseptic filling, phosphatase or peroxidase is released | Not allowed |
| Cleanliness group | Not lower than the first |
A certain temperature of the goods must be observed at the end of its manufacture at the enterprise, ° : for pasteurized, melted, ultra-pasteurized (without aseptic filling) | 4 ± 2 degrees |
| The same temperature parameter, but with aseptic filling, for sterilized milk | from 2 to 25 degrees inclusive |
Requirements for raw materials according to state documents
GOST of drinking milk regulates the requirements for raw materials used for the production of different groups of milk. So, for the manufacture of pasteurized and melted product using:
- Cow's raw milk.
- Cream.
- Skimmed milk.
- Buttermilk, which should be obtained in the production of sweet cream butter.
GOST 31450-2013 also regulates raw materials for products such as sterilized and ultra-pasteurized product.
Cow's milk is used here, but at the same time its acidity should not exceed 18 ° T, the content of somatic cells in the product should not be more than 500 thousand / cm 3 , and thermal stability by alcoholic test is required not lower than the third category.
Skim milk and cream are also used for production. Buttermilk is also included, but the acidity of the component should not exceed 17 ° T.
Start of production
The production of drinking milk according to specifications should begin with an assessment of the quality of the feedstock. This work is carried out by a specialized laboratory. If there is a positive conclusion, the raw materials are allowed for further use. The acceptance of milk and other necessary components is carried out by weight. Raw materials must be cleaned and cooled to a temperature of 4 to 6 degrees Celsius. In addition, the original products (milk, cream) must also be sorted and reserved in such a way as to ensure continuous production of goods.
Further, according to document 31450-2014, drinking milk that has been selected by quality should be normalized by percentage of fat. The desired consistency is achieved by adding (mixing) or selecting part of the cream. All work is carried out in streaming mode.
The way to normalize fat content by mixing requires strictly regulated actions. Depending on the final result, the following will be added to whole milk:
- Fat-free product if whole fat content is too high.
- Cream, if the fat content of whole milk is inferior to the requirements of normalized.
To calculate the exact amount of additives required for mixing, use a separator - cream separator. Part of the milk is separated on this equipment. During this procedure, buttermilk can be used, the amount of which will not exceed 70% of the total mass of the non-fat component used for the subsequent normalization of the whole product. These two components can be mixed together and then added to whole milk, but the amount of buttermilk in any case should not exceed 70%.
Normalization process
The production of drinking milk according to GOST specifications presupposes a process called normalization.
This procedure is carried out in a stream, and the following sequence is used in it: a separator-normalizer-milk cleaner. Using these regulated actions, it is possible to simultaneously purify and normalize whole milk fed to the separator from the regeneration section of the pasteurization cooling plant. The temperature of the components should be 45-60 degrees Celsius, and the amount of supplied material depends on the level of productivity of the installation itself.
As a result of this process, cream is released that are collected separately, and normalized milk. After the step described above, it will undergo homogenization and then return to the pasteurization section. According to GOST 31450-2013 and technical specifications, drinking milk is homogenized to improve taste. This procedure is mandatory for goods with a fat content of 3.5%, and it is also recommended that it be carried out for products with a fat content of 1%, 1.5%, 2.5%, 3.2%. This procedure is not able to directly affect the taste. However, homogenization affects the viscosity of the composition. As a result, the taste qualities of the final product also change.
Purification and the following procedures after homogenization
Drinking milk according to GOST 31450-2013, the technical parameters of which are indicated in this document, must undergo a cleaning step. It is carried out in centrifugal milk cleaners. This stage is necessary and does not depend on the method used to normalize milk. Cleaning takes place at a temperature of 40-45 degrees Celsius. Immediately after this, the product is sent for homogenization under a pressure of 12 ± 2.5 MPa. The temperature during this process is maintained at 45 degrees Celsius. According to the technical conditions of GOST 31450 drinking milk, it is allowed to carry out the homogenization process even at pasteurization temperature.
Product filling
Pasteurized drinking milk is obtained by holding for about 15-20 seconds in a temperature medium of 76 ± 2 degrees Celsius. Most often, a plate pasteurization-cooling unit is used to carry out this procedure. However, the temperature may vary, which depends on the mechanical and bacterial contamination of the feedstock. One of the convenient features of plate pasteurization and cooling plants is the ability to record a thermogram, which indicates the temperature at which pasteurization was carried out.
This function allows you to accurately monitor the effectiveness of this procedure, carried out during the manufacturing process. The thermogram is stored a year from the date of its release.
The production of drinking milk involves the use of automatic systems. So, in automatic mode, the pasteurization temperature is controlled and changed. In addition, this equipment is equipped with a locking system and a check valve. These parts do not allow an unpasteurized product to exit the installation. If the process is not completed, the milk is separately displayed in a special intermediate (balancing) tank. It will be re-delivered to the pasteurization chamber with new portions of the crude product.
After passing this procedure and subsequent cooling to 6 degrees Celsius, the finished milk is fed to the filling and capping or in an intermediate tank. It is allowed to store the product for 6 hours. In some cases, it happens that due to production needs, milk is stored longer. In this case, before bottling and capping, pasteurization should be repeated. In addition, the total shelf life of such a product is reduced by the period that it was in the intermediate tank after 6 hours.
According to regulatory documents, milk contains quite a bit of vitamin C. This substance is easily oxidized, a significant part of it is lost during processing. Therefore, in order to enrich the product with vitamin C, fortified milk is produced. It is somewhat more expensive than usual, but still in high demand. Another separate category is drinking ultra-pasteurized milk. This product is characterized in that the temperature for its processing is maintained even higher than for ordinary milk. As a result, any living microorganisms die in it. For this reason, it is often called sterilized.
Baked and reconstituted milk
To obtain baked milk, it is necessary to conduct the process of its processing in a special tank. In this case, tubular pasteurizers are used. They allow you to heat the feedstock to a temperature of 95-98 degrees Celsius.
It is after heating and placing in a special tank for heating that milk is held for a certain time. 3-4 hours is necessary for a product with a fat content of 4 and 6%, and 4-5 hours - with a fat content of 1%. The same amount of time is maintained for non-greasy raw materials so that it acquires a cream shade. Here it is important to take into account one feature - after cooling the baked milk, its color will be more saturated, that is, dark.
During infusion in tanks, stir the product periodically. This is necessary to avoid the appearance of film and sludge fat.
Ready baked milk is cooled to 8 degrees Celsius and packaged in consumer packaging. Then it is cooled to 4-6 degrees Celsius in cold stores. The shelf life and sales after the end of the technological process is 36 hours, including the shelf life at the factory, which is no more than 18 hours.
The reconstituted milk is separately developed and produced. It should be noted here that the following raw materials can be used for its production:
- Whole milk.
- Whole dry.
- Fat-free dry.
In the latter embodiment, dry buttermilk is also used. It is important to note here that such a product in its organoleptic, physico-chemical, sanitary-hygienic standards should not differ from the usual. The production of such milk, as a rule, is resorted to in those areas where climatic conditions do not allow breeding and keeping cattle.
Work with dry components
It is worth noting that the process and its sequence in the manufacture of milk from dry components is almost no different from working with conventional feedstock. The only and significant difference is its preparation, that is, the restoration of dry components.
In this case, the assessment of the quality of raw materials and their acceptance are that it is necessary to check the solubility of the powder, as well as its physico-chemical properties. In the manufacture of pasteurized milk from dried components, they must be of high quality. Get them by spraying.
All dry raw materials to be reconstituted must be sieved. After that, it is dissolved in hot (45-60 degrees Celsius) drinking water of the highest quality. To carry out the recovery process, special units with a mixing function are usually used in production. So that the prepared mixture does not turn out to be too acidic, it must be immediately cooled after cooking to 5-8 degrees Celsius.
At this temperature, the products are aged from 3 to 4 hours. During this time, the proteins swell, the watery taste is eliminated, the desired density is achieved. The end of the aging process is set according to the density of milk at a temperature of 20 degrees Celsius. After this, a study of the chemical composition is carried out. If necessary, the product is normalized to the desired rate.
Milk with additives
To date, the dairy industry is well developed. In addition to making the product familiar to everyone, companies are engaged in the production of milk with various special additives. It can be sugar, coffee, cocoa, fruit or fruit and berry juices. If coffee or cocoa is used as an additional component, then milk is made in accordance with TU 10-02-02-789-11-89 specifications.
The technological process for obtaining this product is similar to the production of a pasteurized product, but with the difference that in the end it is necessary to add additional components to the composition. This requires a small correction in the manufacturing process manufacturing conditions.
Conclusion
Any milk needs careful quality control. It is carried out throughout the production process, as well as after its completion. All inspection data is always entered in a special laboratory control journal. After that, a special certificate is issued for each batch, allowing its implementation. Therefore, you can safely purchase milk in stores of the distribution network. The main thing is to make sure that the sales period on each package is not violated.
We got acquainted with how the production of all types of milk is currently being carried out.