Bioindicators are used to indicate adequate sterilisation conditions within a steam sterilisation chamber eg autoclave, lyophiliser. The indicators are usually sealed glass ampoules that contain nutrient broth, sugar, a pH indicator and an organism that produces spores. Normally Geobacillus stearothermophilus is the chosen organism. When sterilised at the correct temperature and time the spores should be totally killed. At insufficient temperatures or lower exposure time the spores can survive at least partly which would indicate a fail. After sterilisation the ampoules are incubated at temperatures 55- 60°C for a minimum of 48 hours.
The success of the sterilisation process is checked by means of a colour change. No growth of Geobacillus stearothermophilus which is usually no change in colour indicates adequate sterilisation (a pass), whereas growth usually indicated by a change of colour to yellow shows inadequate sterilisation (a fail).
We can supply biological indicators for use and perform the incubation for test. We can also offer a comprehensive report including photos of each individual indicator plus controls.