Using the Merck Sterikon® plus Bioindicator System it is possible to check the efficiency of autoclaving cycle for 15 minutes at121°C.
Furthermore it is possible to control the sterilization success of any kind of autoclave-loading after autoclaving.
pharmaceuticals, especially drugs in ampoule form, canned food,culture media, etc.
In the USP and EP the use of a bioindicator for the autoclavation control of pharmaceutical products is recommended.
The Sterikon® plus Bioindicator consists of an ampoule that contains a nutrient broth, sugar, a pH indicator and spores of a non-pathogenic organism, Geobacillus stearothermophilus ATCC 7953 (sporulation optimized). The thermal resistance is such that the spores are completly killed after 15 minutes, when heated in compressed steam at a temperature of 121 ± 0.5°C (245kPa). At lower temperatures or lower exposure times a small number of spores can survive and are capable of growing.
The ampoules are placed into the autoclave along with the batch to be autoclaved. After autoclaving, the success of the sterilization process is checked by incubation of the ampoules:
No growth of Geobacillus stearothermophilus indicates adequate sterilization, whereas growth shows inadequate sterilization.
An appropriate number of ampoules are included in the batch to be autoclaved. Autoclaves with a capacity of up to 250litres should be checked with at least 2 ampoules, whilst those with a capacity of more than 250 litres should have at least 6 ampoules.
In order to avoid contamination by accidental breakage, it is advisable to place the ampoules in a glass beaker.
The ampoules are placed in the autoclave at sites where the most unfavourable conditions for sterilization are thought to exist, i.e. at the bottom and in the middle of the autoclave. If a single large volume of material is to be autoclaved (e.g. flasks containing a liquid), a test using the bioindicator is possible only when the ampoule is placed in the centre of the vessel in question (e.g.suspended in a flask or immersed in the contents of a tin of food).
The Sterikon® plus Bioindikator can also be used to check the functional efficiency, i.e. to test whether the prescribed temperature of 121°C is reached within the entire autoclave and whether the temperature remains constant over the whole of the prescribed period of 15 minutes.
After sterilization, the ampoules are removed and incubated 48hours at 60 ± 2 °C. A non-sterilized ampoule should also be incubated to serve as a control. Use of the ampoules at temperatures exceeding 125°C sterilization temperature should be avoided to prevent the possibility of damaging the bioindicator.