The fat content of natural cow's milk ranges from 3.6% to 4.2%. It depends on the diet of the cow, her breed and the season. Today, with the help of modern technologies, it is possible to regulate the fat content of milk according to human needs and influence its shelf life.
Milk contains milk fat, which contains a protein-lecithin complex and arachidonic acid, which have a beneficial effect on human metabolism, thanks to which it is perfectly digested and absorbed by the body.
Fat content of milk
Previously, a person could influence the fat content of milk only by adjusting the nutrition of his cow. Over time, a lot has changed, now, with the help of standardization technology, it has become possible to vary the fat content of milk from 0.5% to 6%.
By mixing cream and skim milk in different proportions, milk of different fat contents can be obtained. So, milk with a fat content of less than 0.5% is called skim milk. Low fat milk is a product with a fat content of 0.5% to 2.5%. A 3.2% fat content is observed in medium-fat milk, and finally, high-fat milk, with a fat content of 4% to 6%. In order to preserve milk for a long time, heat treatment is used.
Heat treatment and storage of milk
There are several methods of thermally processing milk. Pasteurization is the most gentle heat treatment, which retains the maximum amount of beneficial microorganisms. It is carried out at a temperature of 63 ° C to 95 ° C for several minutes. Pasteurized milk, depending on the container, which is film, carton and Tetra Pak packaging, has a shelf life of 4 to 15 days at a temperature of 6 ° C.
The next method of heat treatment is ultra-pasteurization, the milk is heated at an ultra-high temperature of 135 ° C for 3-4 seconds, then immediately cooled to 4 ° C -5 ° C. UHT milk can be stored at room temperature for 6 to 8 weeks. The same milk is packaged as sterilized in Tetra Pak containers.
The most aggressive method is sterilization, in which the raw material is heated to a temperature of 110 ° C -150 ° C, lasting from 10 to 30 minutes. Sterilized milk has the longest shelf life from 6 months to a year.
Milk of different fat content is stored for exactly the same time. The shelf life is influenced only by the way it is processed. It is necessary to control that the packaging of the product is undamaged and that the temperature regime is observed, then the expiration dates will correspond to the dates indicated on the container.
