The heat sterilization method uses high temperature to coagulate or denature the bacterial protein, the enzyme loses activity, the metabolism occurs, and the bacteria die. Thermal sterilization methods include moist heat sterilization and dry heat sterilization. Damp heat can cause the bacterial protein to coagulate and deform; dry heat can oxidize, denature, carbonize and concentrate the electrolyte to cause cell death. The heat sterilization is convenient, the effect is good, and it is non-toxic. It is the main sterilization method used by the hospital disinfection supply center. The pressure steam sterilization method is the preferred sterilization method for wet and heat resistant medical devices.
Pressure steam sterilization uses moist heat sterilization. At the same temperature, the moist heat sterilization effect is better than dry heat, for the following reasons:
1. The temperature required for protein coagulation is related to its water content. The greater the water content, the lower the temperature required for solidification to occur. The bacterial protein at the time of moist heat sterilization absorbs moisture and is thus more likely to solidify than dry hot air at the same temperature.
2. The steam releases a large amount of latent heat during the moist heat sterilization process to further increase the temperature. At the same temperature, the heat sterilization time is shorter than the dry heat.
3. The penetration force of the hot and humid gas is stronger than that of the dry hot gas, so the moist heat is better than the dry heat. High-pressure steam can kill all microorganisms, even bacteria such as bacterial spores, fungal spores and other high temperature resistant individuals. The sterilized steam temperature increases as the vapor pressure increases, and the sterilization time can be greatly shortened by increasing the steam pressure. It is therefore one of the most effective and widely used methods of sterilization.