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Sterilization Best Practices

Steam sterilizers rely on three factors - time, temperature, and pressure - to destroy bacterial and viral contamination and ensure hygienic instruments. Although sterilizers do occasionally need maintenance, repair, and replacement, many problems can be avoided simply by following a protocol designed to make sure that every load run through the sterilizer results in sterile instruments and negative biological monitoring tests. Carefully following sterilization best practices can avoid frustrating positive tests, and guarantee that every instrument is safe and sterile.

Temperature

Check the sterilizer’s owner’s manual for recommendations on proper running of the sterilizer. Many sterilizers should be preheated with an empty run prior to sterilizing instruments. Some sterilizers have different settings (instruments, rapid cycle, liquids) and the sterilizer should be set properly according to the load being sterilized.

Many steam sterilizers, especially older ones, require a great deal of energy to achieve proper temperatures. Sterilizers should be plugged into their own outlet to avoid having available power shared by other energy hungry devices such as microwave ovens or air conditioners.

The temperature the contents reach is also affected by the size of the load. Overloaded sterilizers can have areas with poor circulation that do not reach high enough temperatures to attain sterilization conditions. Adequate circulation is necessary for sterilization. Resist the temptation to overload the sterilizer.

Pressure

Steam sterilizers use the pressure of steam to assist in the destruction of microbes and viruses. If the sterilizer is unable to make or hold steam an important aid to sterilization is missing. This can result in failure to sterilize or the failure of a biological indicator test.

Sterilizers must be kept clean to be able to make steam for sterilizations. Follow the manufacturer’s recommendations for type of water (distilled, filtered, etc.) to be used in the machine, and perform preventative maintenance as needed to avoid buildup. If the sterilizer cycle seems to be taking longer than usual consider calling your sterilizer maintenance service provider for a cleaning and tune up.

Frequently monitor the seal or gasket around the sterilizer door to ensure that cracks are not developing that could allow steam to escape. Periodically check the sterilizer during a cycle for visible or audible steam leaks. If the sterilizer area seems wetter, drier, or smells odd during or after the cycle investigate the cause of the change and re-sterilize the load.

Time

For complete sterilization the necessary temperature and pressure must be held for the correct time. Check your sterilizer’s owner’s manual for proper settings for your machine. Brief power fluctuations can disrupt the cycle, leading to sterilization failure. If you are not sure the sterilizer has completed its cycle repeat the run to ensure that sterilization has been achieved.

In many sterilizers the time after the cycle, when the machine is cooling down, is also a necessary part of the sterilization process. If the owner’s manual advises not opening the sterilizer for a specified period after the cycle, the door should not be opened until the recommended amount of time has elapsed. Failure to do so shortens the time the instruments are held at sterilization conditions, and can compromise the results of the monitoring test.

Testing

To ensure that the biological monitoring test is accurately monitoring sterilizer conditions, the strip should be run in a standard load with instruments for a normal cycle. The strip should not be placed in a wrapper, but should be placed on top of wrapped cassettes/instrument packs near the center of the sterilizer. If the strip is blown around during the cycle the strip may be lightly taped to the outside of a pack prior to sterilization.