What are the specific methods of moist heat sterilization?

Bacteria are everywhere in our lives and have a great impact on our lives. Therefore, we have come into contact with many sterilization methods in our lives, among which the most typical one is moist heat sterilization. In many cases, moist heat sterilization is required for disinfection. Therefore, the specific method of moist heat sterilization is a matter of concern to everyone. So, what are the specific methods of moist heat sterilization? Let’s take a closer look at it.

The main factors affecting moist heat sterilization include: the type and quantity of microorganisms, the nature of the steam, the nature of the drug and the sterilization time.

(1) Circulating steam sterilization: refers to the method of killing microorganisms by heating with 100 degrees Celsius circulating steam under normal pressure conditions. The sterilization time is usually 30-60 minutes. This method is suitable for disinfection and sterilization of preparations that are not resistant to high temperatures, but it cannot guarantee the killing of all spores and is an unreliable sterilization method.

(2) Intermittent steam sterilization: Use repeated circulating steam heating to kill all microorganisms, including spores. The method is the same as circulating steam sterilization, but it must be repeated more than 3 times. During each interval, the object to be sterilized is placed in an incubator at 37°C overnight to allow the spores to develop into reproductive bodies. If the sterilized object cannot withstand the high temperature of 100℃, the temperature can be lowered to 75℃~80℃, the heating time can be extended to 30~60 minutes, and the number of times can be increased. Suitable for culture media containing sugar or milk that are not resistant to high heat.

(3) High-pressure steam sterilization: 103.4 kPa steam pressure, temperature reaches 121.3°C, maintained for 15-20 minutes.

Moist heat sterilization method Moist heat sterilization method can achieve the same sterilization effect as dry heat method at a lower temperature because: ① Protein absorbs water in moist heat and is easier to coagulate and denature; ② Water molecules have greater penetrating power than air and are easier to transfer heat energy evenly; ③ Steam has latent heat. Every gram of water that changes from gas to liquid can release 529 calories of heat energy, which can quickly increase the temperature of an object.

Moist heat sterilization generally uses 121°C for 20-30 minutes. If the microorganism is spore-forming, it should be cultured at an appropriate temperature for several hours after sterilization and then sterilized again to kill the newly germinated spores.

The above is an introduction to the specific methods of moist heat sterilization. I hope it will be helpful to everyone’s understanding. There are many methods of moist heat sterilization, which are relatively simple measures. We can learn about them in detail and use them in our daily lives. However, many of these methods require professional equipment, so you can choose the one that suits you.