The first step: milking and sealing

Generally, the freshly squeezed milk is first put into the milk tank and cooled quickly to prevent the reproduction of microorganisms and prolong the antibacterial properties of the milk. duration. The cooled milk needs to be sent to the factory for processing in time. That is, after filtration, purification, cooling, homogenization, sterilization and packaging, it becomes sterilized milk for daily drinking.

The second step: filtration, defatting and homogenization

After inspection, the disease-free and harmless milk will directly enter the factory through the pipeline for pre-filtration, separation and homogenization. deal with.

Filtration is the basis for milk purification. Tiny hay, feed, hair and other impurities in the "raw milk" will be removed here, so that the milk can be considered pure.

Separation, using the different specific gravity of different substances, further removing impurities through centrifugation and purifying the milk. Separation is an indispensable part of processing skim milk. According to the different needs for milk, different centrifuges can be selected to achieve the effects of sterilization, fat standardization and defatting respectively.

There is a special link in the pretreatment process of milk products - homogenization. Fresh milk contains fat particles of varying sizes. Since fat is lighter than water, if left untreated, the fat particles will float to the surface, causing milk stratification.

The homogenizer uses the principle of sudden release of pressure under high pressure to crush the fat particles in the milk. A high-quality homogenizer can even crush the fat particles to less than 1 micron, which is about the diameter of a hair. One-tenth of. This can ensure that the fat particles in the milk are not easy to float and make the milk concentration uniform.

The third step: core - sterilization

The pretreated milk has no impurities, but it is still riddled with "bacteria". Sterilization is an important step in milk processing. Only after passing the test of this level can the milk be truly "purified" from the outside to the inside.

The common methods of sterilizing milk are pasteurization and ultra-high temperature instant sterilization (UHT). Generally speaking, UHT destroys bacteria more thoroughly, so it can be stored for a longer time.

Step 4: Put the milk into new clothes

From the moment the milk enters the factory until it enters the filling machine, it is completely closed and cannot come into contact with the outside world. This can not only resist the invasion of foreign enemies, but also prevent it from deteriorating due to environmental changes.

In the filling machine, the processed milk is instantly sealed into paper packages. Of course, the paper rolls of these packages have already been strictly sterilized and disinfected before.

China News Network - Reporters directly inspected Yili’s finished milk production process, with a total of 899 inspections