What is pasteurization?

Pasteurization, that is, low-temperature disinfection, is to heat food at low temperature (generally 60 ~ 82℃) for a certain period of time to kill microbial nutrients. It can not only kill germs, but also keep the flavor of nutrients in the goods unchanged.

This is a disinfection method invented by French biologist louis pasteur in 1862. Mainly used in milk to kill germs contained in milk.

It can also be used for disinfection of beer, liquor, etc. Pasteurized beer is called cooked beer, which is ordinary beer; Draft beer is beer that can only be frozen and kept fresh without pasteurization.

Extended data

Main principles

Pasteurization is to heat the mixed raw materials to 68 ~ 70℃, and keep this temperature for 30 minutes and then quickly cool it to 4 ~ 5℃, because the lethal point of bacteria is generally 68℃, less than 30 minutes.

Therefore, the mixed raw materials can kill pathogenic bacteria and most non-pathogenic bacteria after being treated in this way. The mixed raw materials suddenly cool after heating, and the sharp change of hot and cold can also promote the death of bacteria.

In a certain temperature range, the lower the temperature, the slower the bacterial reproduction; The higher the temperature, the faster the reproduction (generally, the suitable temperature for microbial growth is 28℃-37℃), but if the temperature is too high, the bacteria will die. Different bacteria have different optimum growth temperature and heat and cold tolerance.

In fact, pasteurization is to use the characteristics of bacteria that are not very heat-resistant, and treat them with appropriate temperature and heat preservation time to kill them all. However, a small amount of harmless or beneficial bacteria or bacterial spores remain after pasteurization, so pasteurized milk should be stored at about 4℃, and it can only be stored for 3 ~ 16 days at most.

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