Steam sterilization of materials is a dependable procedure for the destruction of all forms of microbial life. Steam sterilization generally denotes heating in an autoclave utilizing saturated steam under a pressure of approximately 15 pounds per square inch (psi) to achieve a chamber temperature of at least 121ºC (250ºF) for a minimum of 15 minutes (for small loads). The time is measured after the temperature of the material being sterilized reaches 121ºC (250ºF).
Mechanical indicators such as pressure gauges and thermometers are widely used to verify proper autoclave operation. However, these are considered secondary to the use of appropriate biological indicators placed on or throughout the material being autoclaved. The biological indicator most widely used for wet heat sterilization is a Bacillus stearothermophilus spore suspension or strip. If sterilization is associated with patient diagnosis, the biological indicator and associated documentation is required by law, as these are the best indicator of sterilization.
The FSU Biological Safety Office tests departmental autoclaves annually using the B. stearothermophilus spore test. Additional testing may be requested if sterilization problems have been observed or are suspected. Call the Biological Safety Office for more information.
FSU researchers should test every sterilization load with autoclave tape or other indicators. The choice of sterilization test may be made at the discretion of the researcher. Information provided below may assist researchers in selecting the appropriate autoclave verification method.