What is Bath sterilization and what are the types of pasteurization?

Bath sterilization is also known as pasteurization.

Pasteurization, also known as low-temperature sterilization and cold sterilization, is a disinfection method that uses a lower temperature to kill germs and maintain the flavor of nutrients in items, and is often used broadly to define heat treatment methods that need to kill various pathogenic bacteria.

Pasteurization is to heat the mixed ingredients to 68 70, and maintain this temperature for 30min, and then cool rapidly to 4-5. Because the lethal point of general bacteria is below the temperature of 68 and the time is less than 30min, the pathogenic bacteria and most of the non-pathogenic bacteria in the mixed raw materials can be killed after this treatment; Sudden cooling of the mixture after heating can also lead to the death of bacteria due to the sudden change in heat and cold [2].

Within a certain temperature range, the lower the temperature, the slower the bacteria will multiply; The higher the temperature, the faster the reproduction (the suitable temperature for the growth of microorganisms is generally 28-37). But if the temperature is too high, the bacteria will die. Different bacteria have different optimal growth temperatures and ability to tolerate heat and cold.

Pasteurization is actually to take advantage of the characteristics of pathogens that are not very heat-resistant, treat them with appropriate temperature and holding time, and kill them all. However, after pasteurization, a small part of harmless or beneficial, heat-resistant bacteria or bacterial spores are still retained, so pasteurized milk should be stored at a temperature of about 4, and can only be stored for 3 10 days, up to 16 days.

There is a wide variety of pasteurization procedures in use today. The "Low Temperature Long Term" (LTLT) process is an intermittent process that is only used by small dairies today to produce some cheese products. "High Temperature Short Time" (HTST) processing is a "flow" process, usually carried out in plate heat exchangers, and is now widely used in the production of drinking milk.

The product obtained in this way is not sterile, i.e. it still contains microorganisms and needs to be refrigerated during storage and handling. "Rapid pasteurization" is mainly used in the production of yogurt dairy products. There are two main types of pasteurization methods commonly used in the world:

One is to heat the milk to 62 65 and hold it for 30 minutes. Using this method, it can kill all kinds of growth pathogenic bacteria in milk, and the sterilization efficiency can be reached, and only some thermophilic bacteria and heat-resistant bacteria and spores remain after disinfection, but most of these bacteria are lactic acid bacteria, and lactic acid bacteria are not only harmless to people but beneficial to health.

The second method heats the milk to 75 90 and keeps it warm for 15 16 seconds, which has a shorter sterilization time and higher work efficiency. However, the basic principle of sterilization is that the pathogenic bacteria can be killed, and if the temperature is too high, there will be more nutrient loss.

84 disinfectant solution (pasteurization): is the abbreviation of Pasteur's disinfection method, which is a disinfection method that uses heat below 100 degrees Celsius to kill microorganisms, invented by German microbiologist Pasteur in 1863.

There are generally two methods of pasteurization in use today:

First, the sterilized items are heated to 30 degrees Celsius;

The second is to heat to Celsius and maintain the action time for at least 15 seconds. Due to the low temperature reached by pasteurization, it cannot be sterilized. However, it can kill pathogenic microorganisms such as brucella, tuberculosis bacillus, dysentery bacillus, typhoid bacillus, etc., and can reduce the total number of bacteria by 90 95, so it can reduce the spread of diseases and prolong the use time of items.

In addition, this disinfection method does not destroy the active ingredients of the sterilized food.

There are three types of pasteurization:1. UHT pasteurization: UHT pasteurization is mainly used for coffee, cheese and boxed juice except for Europe, these products will be heated to a temperature beyond the boiling point, 250 (under pressure) conditions for instantaneous sterilization.

The products that come out in this way do not need to be refrigerated, as they are already sterile. Sometimes it is found that after such a high temperature, the product has a cooked taste. There are major drawbacks in this method, such as the aseptic packaging of dairy products after ultra-high temperature pasteurization, which will cause a large loss of some important nutrients in milk, such as vitamins and amino acids, and at the same time, due to the chemical reaction formed by high temperature, the milk will change color and cause more precipitation.

2. Intermittent pasteurization or trough pasteurization: Intermittent pasteurization or trough pasteurization is the earliest form of pasteurization, which heats the product to 145 degrees Fahrenheit for 30 minutes and kills most of the common bacteria. This method requires the use of large tanks or buckets, and therefore a lot of space.

For this reason, only a small percentage of factories use this sterilization method.

3. High temperature short-time pasteurization: high-temperature short-time pasteurization method is a method with a higher temperature and a shorter time, which is a widely used processing method, pasteurization of milk, "heat preservation temperature" is 161F, this method is the continuous processing process of using "heat preservation pipeline", "heat preservation pipeline" is the pipeline transportation system after milk product heating, the size of the pipe is certain, to ensure that the time experienced when the product passes through all the pipes is 15-20 seconds, when the product is sterilized, If the temperature is 161 degrees Fahrenheit or higher, it is called pasteurization, and then the product is cooled and stored.

Pasteur's method of disinfection is to change the envy ().

Hold for 30 minutes.

Hold for 15 seconds.

Hold for 15 seconds.

Maintain 30 minutes of nuclear sock clock.

e.None of the above is right.

Correct answer: ab

Categories: Education Science >> Institution Information.

Problem description: Some foods cannot be heated at high temperatures, otherwise their nutrition and taste will be affected. For these foods, we can quickly heat them to a certain temperature (usually 60 85) for 15 seconds to 30 minutes, and then cool them quickly. This kills most of the microorganisms in the food while maintaining the original taste.

This heating method is called Pasteur sterilization and was developed by the French scientist Louis. Invented by Pasteur.

It is incorrect. Analysis:

That's right. The method of Pasteur disinfection is to heat the sterilized culture to 60 65 minutes, and the disinfection purpose can be achieved in 3o minutes.

The Pasteur disinfection method is characterized by the ability to kill the vegetative cells of microorganisms, especially sporum-free pathogenic bacteria and intestinal bacteria, without destroying the vitamin nutrients. In the cultivation of oyster mushrooms, the culture material is routinely prepared and mixed well, and then fermented. Stuffy Requirements:

Stacked in the shape of a round bow, 2 meters wide and meters high, with no limit on length. The performance of the stockpile is every meter apart, and a 5???, from top to bottom10 cm vents.

Covered with plastic film, tightly closed. ④3? ?

In 4 days, the temperature of the internal material rose to 60 °C65, 30 minutes after turning the pile. Follow the above requirements one more time.

Two fermentation and disinfection, that is, to achieve the purpose of sterilization, can also promote the decomposition of fibrous matter, so that the material exudes mushroom fragrance, which is conducive to the growth of oyster mushroom mycelium.

Pasteurization is also known as pasteurization, pasteurization is mainly a sterilization method of milk, which can not only kill pathogenic bacteria that are harmful to health, but also make milk quality change as little as possible. In 1862, Louis Pasteur, a French biologist who was deficient, invented a sterilization method that could kill the germs in milk, but did not affect the taste of milk, that is, pasteurization.

Most of the milk sold on the market is pasteurized. Pasteurization cannot kill all bacteria, it can only reduce the large number of pathogenic bacteria to a level that does not pose a danger to consumers. Pasteurization can be applied to fermented products in addition to milk.