The white precipitate in milk is protein denatured clot, and the protein in milk is precipitated from the original sol state to the gel state. In addition, the unstable phosphate is transformed from acidic calcium phosphate to insoluble neutral calcium phosphate precipitation. So the "milk scale" was formed. If there is only a small amount of sediment, it will not affect eating. In addition, milk will be slightly bitter due to the precipitation produced by thermotolerant enzymes produced by psychrophilic bacteria decomposing protein. This situation is harmless, but the nutritional value is reduced.

The correct storage method of milk:

1, milk should be kept in a cool place, if the bottle cap has been opened, it is best to put it in the refrigerator. Don't expose milk to sunlight or light. Sunlight and light will destroy several vitamins in milk and make it lose its flavor.

2. When the milk is put into the refrigerator, be sure to cover the bottle cap to prevent other odors from entering the milk. Pour milk into cups, teapots and other containers. If you haven't finished eating, cover it and put it back in the refrigerator. Never pour it back into the original bottle.

3. Fresh milk is freshly squeezed milk. Without sterilization, it can be stored below 4℃ for 24-36 hours, preferably in the fresh-keeping layer of refrigerator.