AN-2203 - Biological Indicators

These self-contained biological indicators (BIs) set the gold standard for sterility assurance. They contain a minimum of 1x10⁶ Bacillus atrophaeus spores. No need for aseptic conditions as they are self-contained, with the growth media stored inside the BI in a glass vial. Results are available in just 48 hours.

To determine whether all the spores in the indicator tube have been killed during the sterilisation cycle they need to be exposed to growth medium and incubated at 37°C for 48 hours. The growth medium is contained in a glass vial within the indicator tube and the medium is released onto the spore strip by bending the tube to crack the glass vial. Incubation may be done in an incubation cabinet or using the 14 well incubator (AN-2205).

If the culture medium remains a clear orange after 48 hours incubation then the sterilisation cycle was successful. If the culture medium turns a milky yellow then indicator contained live spores.

The tube also has a colour change indicator band to show when the indicator has been exposed to EtO.

Correctly used these self-contained biological indicators may be used for quality assurance purposes to control the release of loads that have been processed through an EtO sterilisation chamber. They are also appropriate for use in validation studies and may form part of the process challenge device (PCD).