Autoclave quality assurance

2012-02-15

Autoclave quality assurance

There are physical, chemical, and biological indicators that can be used to ensure an autoclave reaches the correct temperature for the correct amount of time.

Chemical indicators can be found on medical packaging and autoclave tape, and these change color once the correct conditions have been met. This color change indicates that the object inside the package, or under the tape, has been processed.

Biological indicators contain spores of a heat-resistant bacterium, Geobacillus stearothermophilus. If the autoclave does not reach the right temperature, when incubated the spores will germinate, and their metabolism will change the color of a pH-sensitive chemical.

Some physical indicators consist of an alloy designed to melt only after being subjected to the relevant holding time. If the alloy melts, the change will be visible.

Some computer-controlled autoclaves use an F0 (F-nought) value to control the sterilization cycle. F0 values are set as the number of minutes of equivalent sterilization at 121 'C (250 'F) at 15 psi (100 kPa) above atmospheric pressure for 15 minutes . Since exact temperature control is difficult, the temperature is monitored, and the sterilization time adjusted accordingly.

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