Protect health with temperature and time

As early as ancient times, people have known the use of fire roasting, boiling, sun and other methods to preserve food, kill or remove microorganisms. Among all kinds of disinfection and sterilization methods, thermal disinfection and sterilization has always been a more traditional, widely used and reliable method, but also a green method without residue.

Thermal disinfection and sterilization is a method to destroy proteins, nucleic acids, cell walls and cell membranes of microorganisms by heat, thus leading to their death. According to the thermal temperature, the commonly used disinfection and sterilization methods can be divided into pasteurization, boiling disinfection, pressure steam sterilization, etc.

Pasteurization - Keep fresh milk safe

Pasteurization, invented by French biologist Louis Pasteur in 1862. At that time, in order to prevent the wine from becoming sour, the wine was heated to 60℃ for a certain period of time to kill the lactic acid bacteria in the wine, without affecting the quality of the wine itself. This method has been continued to this day and has become the main disinfection method for fresh milk on the market.

There are two main methods of pasteurization commonly used internationally: the first is to heat milk to 62℃-65℃ for 30 minutes. In the second method, milk is heated to 75C - 90C and kept warm for 15-16 seconds.

Little friends note oh, pasteurized milk should be kept at 4℃, and the shelf life is relatively short. This is because pasteurization is good at disinfecting and sterilizing milk while minimizing the loss of nutrients, and there are no chemical additives affecting the taste of milk. But pasteurization, also known as pasteurization, cannot be sterilized to the extent that small amounts of harmless or beneficial heat-resistant microorganisms remain in the milk.

Pasteurization:

Advantages: Minimize the loss of milk nutrients, no chemical additives affect the taste of milk.

Disadvantages: A small amount of harmless or beneficial heat-resistant microorganisms remain, kept at low temperature at 4℃, and the shelf life is short.

Boiling disinfection - Always at home

Boiling disinfection is the most common method of home disinfection, simple, economical, convenient and reliable effect. The specific method is to immerse the sterilized items in water and then heat and boil. Start timing after boiling water, generally 5-15 minutes can achieve disinfection effect. This method is mainly applicable to heat and moisture resistant items, such as ceramic, metal, rubber, glass and so on.

Note the following when using the boil method:

1

Items should be washed and submerged, and the water should not be too full. In order to remove organic matter, improve the disinfection effect, disinfection articles need to be cleaned before boiling, boiling immersed in water, water do not fill too full, preferably not more than 2/3 of the container volume.

2

Add new material to boil again, time again. If new items are added during the boiling process or the temperature decreases for other reasons, the time should be reset after boiling again.

3

It can't be used to sterilize. Most bacteria and viruses can be killed at 100℃, but for some heat-resistant bacteria and spores, the disinfection effect is poor, and it takes several hours to kill.

4

At high altitudes, increase the disinfection time or pressure disinfection. The boiling point of water is affected by air pressure, and the boiling point is lower in high altitude areas. Therefore, the disinfection time should be increased during boiling or the pressure cooker should be used to ensure the disinfection temperature.

Pressure steam sterilization - most reliable but not suitable for home use

Pressure steam sterilization is one of the most reliable and effective methods of thermal disinfection. Its principle is to use latent heat in high temperature saturated steam under high pressure for sterilization. But it should be noted that the pressure steam sterilizer belongs to special equipment, which must be operated after training. The sterilization temperature and time should reach 121-126℃, 15-30 minutes or 132-134℃, 4-6 minutes. The common temperature of household pressure cookers can only reach 110℃-120℃, beyond which the exhaust valve will be automatically opened, and there is no need for sterilization in household scenes, only ordinary boiling disinfection can meet the needs of household hygiene.

Knowledge expansion ↓

In addition to the above three commonly used disinfection and sterilization methods, there is also the flow of steam disinfection method, the use of 100℃ steam disinfection, steamed rice box, steamer, steam disinfection cabinet, steam disinfection car belong to this category.

The disinfection time should be calculated after the water boils and steam emerges. Generally, the disinfection should be maintained for 30 minutes, which can kill the reproductive body of bacteria, but can not kill the spores of bacteria.

Flow steam disinfection method is suitable for the disinfection of non - resistant high - pressure articles. When steam disinfection is carried out, the packaging of disinfection articles should not be too large or too tight to prevent air from remaining in the dead chamber; Absorbent articles do not soak into, otherwise hinder the replacement of air; The cold air in the disinfection cabinet should be excluded during disinfection.

Small partners in the daily disinfection should be according to the disinfection object, the scope of use, choose the appropriate and economic disinfection method, especially pay attention to the control of disinfection temperature and time. The selection of thermal disinfection methods for different materials mainly depends on the resistance of materials to heat. If you choose too high temperature disinfection will destroy the internal structure of the material, resulting in deformation, cracking and other varying degrees of damage.