End users should monitor their respective sterilization procedures through a combination of physical, chemical, and biological techniques designed to evaluate the sterilizing conditions and the procedures’ effectiveness.

Physical Parameters – Gauges, Displays, Alarms, and Printouts

Techniques for monitoring sterilization efficacy include assessing the cycle time, temperature, and pressure of the steam sterilizer by observing the gauges, displays, alarms, and printouts on the sterilizer. Correct readings do not absolutely assure complete sterilization has occurred, but incorrect readings are the first indication that a problem has occurred with the sterilization cycle.

Chemical Indicators

Chemical indicators use sensitive chemicals to assess physical conditions such as temperature during the sterilization process. Chemical indicators do not prove that sterilization has occurred, only that a certain parameter or parameters has been achieved.

Chemical indicators such as heat-sensitive tape change color rapidly when a given parameter is reached.

An internal chemical indicator can be placed in every sterilization package to ensure steam has penetrated the packaging material and actually reached the instruments inside.

An external indicator can be used when the internal indicator cannot be seen from outside the package.

Single-parameter internal indicators provide information on only one sterilization parameter. Multi-parameter internal indicators for steam sterilizers measure 2–3 parameters and can provide a more reliable indication that sterilization conditions have been met. Always refer to the manufacturer’s instructions for proper use and placement of chemical indicators.

Indicator test results are shown immediately after the sterilization cycle is complete and could provide an early indication of a problem and where the problem occurred in the process. If the internal or external indicator suggests inadequate processing, the item that has been processed should not be used. Again, because chemical indicators do not prove sterilization has been achieved, a biological indicator is required.

Biological Indicators

Biological indicators (BI) are the most accepted means of monitoring the sterilization process because they directly determine whether the most resistant microorganisms (Bacillus spores) are present following sterilization rather than merely determining whether the physical and chemical conditions necessary for sterilization were met.

Because the spores used in BIs are more resistant and present in greater numbers than are the common microbial contaminants found on patient care equipment, an inactivated BI indicates that other potential pathogens in the load have also been killed.

BI Testing

In a healthcare setting, the correct functioning of sterilization cycles should be verified for each sterilizer by the periodic (at least weekly) use of BIs. Users should follow the manufacturer’s directions concerning the appropriate placement of the BI in the sterilizer. A control BI (not processed through the sterilizer) from the same lot as the test indicator should be incubated with the test BI. The control BI should yield positive results for bacterial growth.

In addition to conducting routine biological monitoring, end users should perform biological monitoring under the following circumstances:

  • Whenever a new type of packaging material or tray is used
  • After training new operating technicians
  • After a sterilizer has been repaired
  • After any change in the sterilizer loading procedures

Have a question or having difficulties? Talk to Dave Schall, our PRIMUS sterilizer expert who is here to assist you anytime at 877.679.7800 extension 1212 or email at dschall@spire-is.com.

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