1. What is pasteurization?
The milk pasteuration method was invented by the French user Pasteur in 1865. It was improved by future generations to completely eliminate pathogens in beer, wine, milk, serum albumin, and other liquids, it is also a common milk disinfection method in the world.
The purpose of pasteurization is to kill all possible harmful microorganisms (including all pathogenic bacteria) in milk ). Before the pasteuration method was invented, there were countless people in Europe who had tuberculosis due to drinking raw milk or eating dairy products. Since antibiotics were not invented at the time, countless people died of tuberculosis. However, since the pasteurization method has been widely used, it is rare for people who have this disease due to drinking milk. But now there are some places in the world that people like to drink raw milk, such as China's Inner Mongolia. According to a survey by scientists, 10.6% of the patients with tuberculosis in neimeng herdsmen have the habit of drinking raw milk.
The pasteuration method is also used to disinfect beer, liquor, and other things. The beer that passes the pasteuration is called dry beer. Without pasteuration, the fresh beer can only be frozen.
What is the principle of pasteurization?
Within a certain temperature range, the lower the temperature, the slower the Bacterial reproduction; the higher the temperature, the faster the reproduction. But if the temperature is too high, bacteria will die. Different bacteria have different optimal growth temperature and heat resistance and cold resistance. Pasteural disinfection is actually to take advantage of the characteristics of pathogens that are not very heat-resistant, with appropriate temperature and heat preservation time treatment, killing all of them. However, after pasteurization, a small portion of harmless or beneficial and heat-resistant bacteria or bacterial spore are still stored. Therefore, pasteurization milk should be stored at a temperature of about 4 ℃, and can only be saved for 3-10 days, up to 16 days.
What are the methods for pasteurization?
At present, there are two main types of pasteurization methods in the world: one is to heat milk to-65 ℃ for 30 minutes. This method is rarely used in Guangdong currently. By using this method, various growth-type pathogenic bacteria in milk can be killed, and the sterilization efficiency can reach 97.3%-99.9%. After disinfection, only some of the hot bacteria, heat-resistant bacteria and spore are left, but the majority of these bacteria are lactic acid bacteria. lactic acid bacteria are not only harmless but beneficial to human health. In the second method, the milk is heated to-90 ℃ and kept warm for 15-16 seconds. The sterilization time is shorter and the work efficiency is higher. However, the basic principle of sterilization is that the bacteria can be killed. If the temperature is too high, there will be more nutritional losses.
What are the advantages of pasteurization?
Pasteuration pure fresh milk has good preservation of the Nutrition and natural flavor of milk, which is the best among all milk varieties. I remember that when the sterilized pure milk in the north entered Guangzhou, it once had such propaganda: pasteurized milk only fainted bacteria, a high temperature, bacteria woke up, multiply reproduction. These absurd words have deceived some consumers. "Stun" bacteria are really the creations of these people. I have never heard of bacteria before. After listening to these words, I was overwhelmed. In fact, as long as pasteurized milk is stored at a temperature of about 4 ℃, the reproduction of bacteria will be very slow, and the nutrition and flavor of milk will remain unchanged within a few days.
Pasteurized milk is the most frequently consumed milk in the world. The consumption of pasteurized milk in Britain, Australia, the United States, Canada and other countries accounts for more than 80% of liquid milk, the varieties are full-fat, semi-fat, or full-fat. In the U.S. market, almost all of them are pasteurized milk, which is packed in large packages (1 litre, 2 litre, and 1 gallon). Citizens buy enough fresh milk for a week at a supermarket. The market seldom sells sterilized pure milk, and some small towns cannot buy it.
Ii. Super High Temperature Sterilization
Ultra-high temperature sterilization is an instantaneous sterilization process after ultra-high temperature instantaneous sterilization (135 deg C to 150 deg C, 4 to 15 seconds), completely destroying the growth of microorganisms and spore
