Introduction of two main methods of pasteurization

used today.pasteurizationThere is a wide variety of procedures. "Low temperature long time" (LTLT) processing is a batch process that is currently only used by small dairy plants to produce some cheese products. "High Temperature Short Time" (HTST) treatment is a "flow" process, usually performed in plate heat exchangers, and is now widely used in the production of drinking milk. The products obtained in this way are not sterile, I .e. still contain microorganisms, and require refrigeration during storage and handling. "QuickpasteurizationMainly used in the production of yogurt dairy products. Internationally commonly usedpasteurizationThere are two main methods:

One is to heat the milk to 62~65 ℃ for 30 minutes. The method can kill a variety of growth pathogens in milk, and the sterilization efficiency can reach 97.3%~ 99.9%. After disinfection, only some thermophilic bacteria, heat-resistant bacteria and spores are left, but most of these bacteria are lactic acid bacteria, which are not only harmless, but also beneficial to health.

The second method is to heat the milk to 75~90 ℃ for 15~16 minutes, the sterilization time is shorter and the work efficiency is higher. But the basic principle of sterilization can kill pathogenic bacteria, but the temperature is too high, the loss of nutrition will be more.

Note: PU,60 ℃ for 1 minute, sterilization strength is PU.

pasteurizationThe degree of heat treatment is low, generally heating at a temperature lower than the boiling point of water, and the heating medium is hot water.

Different foods arepasteurizationused for different purposes. Certain foods, especially milk, whole eggs, egg whites and egg yolks, pass throughpasteurizationThe main purpose is to destroy possible pathogenic bacteria, such as Mycobacterium tuberculosis and Salmonella. In addition, most foods such as beer, cider (wine) and fruit juice go throughpasteurization, The purpose is to extend the shelf life of the product from the perspective of microorganisms and enzymes.

Generally speaking,pasteurizationFoods still contain many viable microorganisms, often thousands per milliliter or gram, and have a shorter shelf life than commercially sterilized products.pasteurizationTechnology is not only used in liquid food (juice, milk), acidic food and canned jam, but also penetrated into other fields. For example, when handling oysters with shells, steam treatment reduces the number of bacteria in oysters. Its advantage is that it can process food at a lower temperature and in a shorter time, thereby protecting the color, aroma, taste and nutrients of food from high temperature and long-term processing damage to food

It is mainly a sterilization method of milk, which can not only kill pathogenic bacteria harmful to health, but also minimize the quality change of milk. That is, according to the principle that the heat-extinguishing curve of Mycobacterium tuberculosis with strong high temperature resistance is different from that of the cream which is most easily heated in milk, it is treated at low temperature for a long time or at high temperature for a short time. Methods. Among them, the method of heating below 60°C for 30 minutes has been widely used as a low-temperature sterilization standard in the world. The use of high temperature treatment has a certain impact on the quality of milk, but can enhance the sterilization effect. This method is called high-temperature sterilization (sterilization), that is, heating above 95°C for 20 minutes. In addition to the milk,pasteurizationIt can also be applied to fermented products.