Because a small number of harmless or beneficial, heat-resistant bacteria or bacterial spores still remain after pasteurization, pasteurized milk should be stored at a temperature of about 4°C and only Can be stored for 3~10 days, up to 16 days.

"Rapid pasteurization" is mainly used in the production of yogurt and dairy products. There are two main types of pasteurization methods commonly used internationally:

One is to heat milk to 62~65℃ and keep it for 30 minutes. Using this method, various growth-type pathogenic bacteria in milk can be killed, and the sterilization efficiency can reach 97.3%~99.9%.

Only some thermophilic and heat-resistant bacteria and spores remain after disinfection, but most of these bacteria are lactic acid bacteria, which are not only harmless to humans but beneficial to health. ?

The second method heats the milk to 75~90℃ and keeps it warm for 15~16 seconds. Its sterilization time is shorter and the work efficiency is higher. However, the basic principle of sterilization is that it can kill pathogenic bacteria. If the temperature is too high, there will be more nutritional losses.

Extended information

Different foods use pasteurization for different purposes. Pasteurization of certain foods, especially milk, whole eggs, egg whites and egg yolks, mainly destroys possible pathogenic bacteria such as Mycobacterium tuberculosis and Salmonella.

In addition, the purpose of pasteurization for most foods, such as beer, cider (wine) and juice, is to extend the shelf life of the product from the perspective of microorganisms and enzymes. Generally, pasteurized food still contains many microorganisms that can grow, usually thousands of viable bacteria per milliliter or per gram, and the storage period is shorter than that of commercially sterilized products.

In addition to being used in liquid foods (juice, milk), acidic foods, canned jams, etc., pasteurization technology has also penetrated into other fields. For example, when processing shelled oysters, steam treatment will reduce the quality of the oysters. Bacteria count.

Its advantage is that it processes food at a lower temperature and in a shorter time, maximizing the color, aroma, taste and nutrients of the food from being damaged by long-term processing at high temperatures.

It is mainly a sterilization method for milk, which can kill pathogenic bacteria harmful to health and minimize changes in milk quality. That is, based on the principle of difference between the thermal death curve of Mycobacterium tuberculosis, which is extremely resistant to high temperatures, and the separation thermal damage curve of cream, which is the most susceptible to heat in milk, it is a kind of heat treatment at low temperature for a long time or at high temperature for a short time. method.

Baidu Encyclopedia-Pasteurization