principle:
Within a certain temperature range, the lower the temperature, the slower the bacteria multiply; the higher the temperature, the faster the reproduction. But if the temperature is too high, the bacteria will die. Different bacteria have different optimum growth temperatures and heat and cold resistance. Pasteurization is actually the use of pathogens that are not very heat-resistant. They are treated with appropriate temperature and holding time to kill them all. However, after pasteurization, a small number of harmless or beneficial, heat-resistant bacteria or bacterial spores are retained, so pasteurized milk should be stored at a temperature of about 4 ° C and can only be stored for 3 to 10 days. Up to 16 days.
application:
As a sterilization method for milk, Zhangjiagang Xinmao Beverage Machinery Co., Ltd. can kill pathogens that are harmful to health and make milk quality as little as possible. That is, according to the principle of the difference between the heat lethal curve of the tuberculosis which is extremely resistant to high temperature and the heat-destructive curve of the cream which is the most susceptible to heat in the milk, the heat treatment is performed at a low temperature for a long time or at a high temperature for a short time. method. Among them, the method of heating at 60 ° C or lower for 30 minutes has been widely used as a standard for low-temperature sterilization. The use of high temperature treatment, although somewhat affecting the milk quality, can enhance the sterilization effect. This method is called sterilization, that is, heating at 95 ° C or higher for 20 minutes. In addition to milk, the pasteurization method can also be applied to fermentation products, food sterilization after vacuum packaging, and the like.
Typically, bagged milk sold on the market is produced by pasteurization. Fresh milk is collected from the factory, first treated at low temperature and then sterilized by pasteurization. Bagged milk produced in this way can usually be stored for a longer period of time. Of course, the specific process and process are much more complicated, but the general principle is this.
It should be pointed out that drinking fresh milk (referred to as milk that has just been squeezed out) is not safe because it may contain bacteria that are harmful to our body. Another point is that pasteurization is not a panacea. The pasteurized milk is still stored at a lower temperature (generally <4 °C), otherwise there is still the possibility of deterioration. Therefore, many methods of selling bagged milk on the market are very irregular.
Pasteurized milk is the most consumed milk in the world. The consumption of pasteurized milk in the United Kingdom, Australia, the United States, Canada and other countries accounts for more than 80% of liquid milk. Zhangjiagang Xinmao Beverage Machinery Co., Ltd. has full degreasing and half. Degreased or full fat. In the US market, it is almost all pasteurized milk, and it is a large package (1 liter, 2 liters, 1 gallon). The public buys enough milk for one week at a supermarket. There are very few sterilized pure milk sold in the market, and some small towns cannot buy them at all.
Pasteurized pure milk preserves the nutritional and natural flavor of milk and is the best of all milk varieties. In fact, as long as the pasteurized milk is stored at a temperature of about 4 ° C, the reproduction of the bacteria is very slow, and the nutrition and flavor of the milk can remain unchanged for several days.