There are many types of pasteurization procedures in use today.The “low temperature long time” (LTLT) treatment is an intermittent process, and now it is only used by small dairy factories to produce some cheese products.”High temperature short time” (HTST) treatment is a “flow” process, usually carried out in plate heat ex-changer, and now is widely used in the production of drinking milk.Products obtained by this method are not sterile, that is, they still contain microorganisms and need to be refrigerated during storage and processing.”Rapid pasteurization” is mainly used in the production of yogurt and dairy products.There are two kinds of pasteurization methods in the world:
One is to heat the milk to 62~65℃ and keep it for 30 minutes.With this method, can kill all kinds of growth pathogens in milk, the sterilization efficiency can reach 97.3%~99.9%, what remain after disinfection are some thermophilic bacteria and heat-resistant bacteria and spore, but these bacteria are mostly lactobacillus, which are not only harmless to the human but also beneficial to human health.
The second method is to heat the milk to 75~90℃ and keep it warm for 15~16 minutes. The sterilization time is shorter and the working efficiency is higher. However, the basic principle of sterilization, is to kill pathogenic bacteria , temperature is too high can have more nutrition loss instead.
Note: PU, heat preservation at 60℃ for one minute is called sterilization strength, is a PU