Moist heat sterilization is a commonly used sterilization method in the laboratory. The biggest difference between it and other sterilization methods is that the sterilization medium is different. For example, dry heat sterilization mainly uses air, while moist heat sterilization uses steam. Different sterilization methods have certain differences in temperature and time.

Then, what is the maximum temperature of moist heat sterilization? What is the principle of sterilization?

The basic principle of sterilization autoclave is as follows: by using impressive vacuum systems to remove the air in the closed room, they can increase the pressure in the container and create a perfect environment for the rapid and effective realization of sterility. The higher pressure also allows the boiling point of water to be higher, which means that the machine can use steam of more than 100 degrees Celsius: to be exact, between 121 and 134 degrees!

why autoclave temperature is 121？

Generally speaking, the higher the sterilization temperature, the shorter the sterilization time. High-pressure sterilization is a sterilization method in which the temperature of sterilization in autoclaves is 121 ° and sterilization lasts for 20-30min, and microorganisms are killed by high temperature and high-pressure steam. By boiling and disinfecting at 100 ° C, it can effectively destroy microorganisms, spores, or viruses that are difficult to be eliminated by traditional disinfection methods.

The culture medium contains the necessary carbon source, nitrogen source, and inorganic salt for the growth of microorganisms. It is usually sterilized with damp heat and high pressure at 121 ℃ for 30min to ensure that bacteria and their spores can be inactivated. Of course, the sterilization effect will be better if the temperature and atmospheric pressure are higher than this, but it may have an impact on the composition of the culture medium.

If it is a spore-producing microorganism, it should be cultured at a suitable temperature for several hours after sterilization, and then sterilized again to kill the newly germinated spores. However, considering the stability of the sterilized material, the sterilization temperature or time can be appropriately reduced under the premise of effective sterilization.

In the experiment of microorganisms (bacteria, fungi, viruses, etc.), if other microorganisms pollute the experiment, the experimental results may be affected. Therefore, the laboratory autoclave of the micropipette, other experimental equipment, and culture medium processed in the experiment are very important to prevent pollution/cross-contamination.

Let’s talk about the maximum temperature of the sterilization autoclave first. In short, different bacteria have different resistance to heat at different stages of development. Generally speaking, the less the number of bacteria, the shorter the sterilization time. If you have other questions, you can consult online on the official website to learn more.