Calibration of Autoclave by Biological Indicator:
- Put five indicators of Bacillus steriothermophilus spores at five different locations in the chamber.
- Run Autoclave at 121°C & 15 lbs pressure for 15 minutes.
- After completion of sterilisation cycle remove biological indicators from autoclave.
- Inoculate the biological indicator in sterile Soyabean casein digest medium tubes.
- Inoculate an unsterilized indicator in sterile Soyabean casein digest tube as positive control and incubate one sterile Soyabean casein digest medium tube without any inoculation as negative control.
- Incubate all the tubes at 55° to 60° for 72 hours.
- If purple colour changes to yellow after 15 to 18 hours: Sterilisation is faulty.
- If purple colour changes to reddish brown after 72 hours: Material is overheated.
- Incubate unopened Ampoules at 56° C for o72 hours if purple colour is retained after 72 hours of incubation. Sterilisation is perfect.
Calibration of Autoclave by using Heat labile Physical Indicator:
- lace five strips of steam clox at five different places in the chamber.
- Run autoclave at 121°C & 15 lbs pressure for 15 minutes.
- After completion of sterilization cycle remove the indicators from the autoclave.
- Observe the colour changes in indicator.
- The colour should change from pink to green.