Autoclave sterilization is one of the most effective and reliable methods for sterile processing. Sterilization cycles use saturated steam under pressure to achieve a chamber temperature of at least 250degF (121degC) for a specified time.

Verifying the correct temperature and time when using an autoclave is vital. There are physical, chemical, and biological indicators can be used to monitor the temperature and time required for each cycle.

Biological Indicators

Biological indicators (BIs) are non-pathogenic, sterilization-resistant microorganisms that provide the best assurance of sterility. They are also crucial to ensuring the effectiveness of sterilization processes and complying with standards and guidelines, such as COVID-19 and AAMI standards.

BIs are spore-forming microorganisms, such as Geobacillus stearothermophilus (GS) and Bacillus atrophaeus, that can withstand the high levels of heat required for steam sterilization, hydrogen peroxide, or ethylene oxide sterilization. They are used to monitor and validate the sterilization process, including estimates of SAL.

Biological indicators are critical to every load monitoring, a practice backed by CDC, AORN, and AAMI standards. A positive BI results for every load released is the first step in confirming that your autoclave sterilizer is sterilizing the load properly. Spore testing is a must for ensuring the highest level of sterility assurance in your sterilization program. It indicates that your sterilizer has killed many highly resistant bacteria, ensuring patient safety.

Chemical Indicators

Chemical indicators measure pressure, temperature, and time in the sterilization process. They can be a paper strip, label, or steam pattern card and may change color to indicate achieved conditions.

They can also be placed inside the packaging of a package to verify that it was exposed to the desired conditions during sterilization. It is essential to sterilize instruments in contact with blood or other fluids.

A standard indicator is a heat-sensitive tape that changes color from white to a visible pattern if the temperature has reached 121 deg C. However, this does not prove that the item is sterile; it only indicates that the outside of the article has made it to this temperature.

Physical Indicators

Laboratory autoclave are practical sterilization tools because they create high pressure and temperature to kill viruses, spore-forming bacteria, and other microorganisms. However, they use a lot of energy and water to operate, so it is vital to select an autoclave to minimize its environmental impact.

One way to do this is to choose green autoclaves that recycle or use less water than traditional autoclaves. Another method is to purchase control systems that automatically turn the autoclave when it is not in use to reduce its energy usage.

To ensure the quality of the results from sterilization cycles, it is necessary to validate them with biological and chemical indicators. Biological indicators contain standardized populations of resistant bacterial spores, such as Geobacillus stearothermophilus. These spores can survive the sterilization process and are used to confirm that sterilization conditions were met during each cycle.

Time Indicators

Autoclaves are a critical and highly effective tool for sterilizing medical devices and other items. They are based on the principle that steam can penetrate materials and kill microorganisms such as viruses and spore-forming bacteria.

The effectiveness of a sterilization cycle depends on the time, temperature, and pressure achieved during the process. Indicators designed to react to one or more of these critical parameters can help verify if the required conditions were met and achieve desired levels of sterility.

Class 5 chemical and biological indicators are available to monitor the autoclave steam sterilization process. They provide proof-positive evidence that the requisite steam penetration, temperature, and time were achieved to produce the desired level of microbial inactivation.

EHS recommends using a biological indicator with every load and a class 5 chemical indicator in addition to autoclave tape. Biological indicators are more reliable than any other type of test and are considered the gold standard for ensuring that your sterilization process achieves the desired microbial inactivation.