1 Principle of sterilization
Autoclaving is a wet heat sterilization method, the principle is: in the closed steamer, in which the steam can not be overflowed, the pressure continues to rise, so that the boiling point of the water continues to increase, so that the temperature inside the pot also increases. At a pressure of 0.1MPa, i.e., 103.4kPa (1.05kg/cm2) steam pressure, the temperature inside the pot reaches 121°C, which is maintained for 15~30min. When the temperature exceeds the temperature range of optimal physiological activity of the cells, the cell metabolism is slowed down, and the cell's proteins, enzymes, and nucleic acids are permanently destroyed, resulting in the irreversible death of the cells. At this steam temperature, can quickly kill a variety of bacteria and their highly heat-resistant spores, is the most reliable and most commonly used physical sterilization method [11].
2 Sterilization verification
Sterilization verification is generally divided into the following parts:
Installation confirmation: first, to confirm the integrity of the sterilizer's random documents and attachments, such as installation records, drawings, computer software, the calibration of the measuring device ( temperature gauge, pressure gauge, time meter ), etc., and secondly, to validate the conformity of the sterilizer's working environment, such as water quality testing, safety requirements, etc., and third, to verify whether the sterilizer installation meets the equipment installation requirements, confirm the concentration of sterilizing agent and quality conditions.
Operation confirmation: verify that the sterilization equipment has the ability to provide a specific process within the specified tolerance, such as heat distribution test, including no-load heat distribution test.
Performance confirmation : physical performance confirmation and microbiological performance confirmation, including full load heat distribution test ( maximum and minimum temperature points ) heat penetration test, etc., the use of biological indicators.
3 Product Release
Daily monitoring requires monitoring the temperature during pretreatment, temperature and pressure throughout the sterilization process. Ultimately, the product can only be released if all bioindicator (BI) cultures are negative and the sterilization process parameters are within the performance-validated parameters.
4 Application
Because autoclaving itself does not destroy the surface of the product and drugs, pharmaceutical solutions, glass instruments, media and other substances that do not change or damage under high temperature and high humidity conditions, can be used autoclaving method. High-pressure steam sterilization has been widely used in a variety of biochemical laboratories and hospitals, for some culture media, glass products, saline and other extinction. The current type of high-pressure steam sterilizer and more styles, such as: ① under the exhaust pressure steam sterilizer is commonly used sterilization equipment, the pressure rises to 102.9kPa (1.05kg/cm2), the temperature reaches l21 ~ 126 ℃, maintain 20 ~ 30min, can achieve the purpose of sterilization. ② Pulsating vacuum pressure steam sterilizer has become the most advanced sterilization equipment. Sterilization conditions require: steam pressure 205.8kPa (2.1kg/cm2), the temperature of l32 ℃ and maintain l0min, can kill all microorganisms, including bacteria with tenacious resistance to germs.
Precautions for high-pressure steam sterilization: (1) must first use the circulation of steam or vacuum to eliminate the air in the cavity of the sterilizer. If there is air in the sterilizer, the pressure indicated on the pressure gauge is the total pressure of steam and air in the sterilizer, the result is that the pressure reaches the requirements, but the sterilization temperature can not be reached, not to achieve the sterilization effect. (2) Sterilization time must be calculated from the time when all the loaded sterilized materials have reached the sterilization temperature. (3) Determination of the loading method, different types of loading must be verified to confirm, to avoid arbitrariness. (4) The autoclave must be periodically verified.