[Testing the sterilisation effect of autoclaves by means of biological indicators (author's transl)]

Because of the great number of failures with sterilization-programs it seems to be necessary to check up the effect of sterilization not only by the annual official tests but also continuously with biological indicators. Marketable indicators have not to be tested necessarily at present. Therefore six different types of indicators were examined experimentally and under practice-conditions. As to be seen in table 1 samples of the same charge didn't show great differences, in spite of this germ-counts of several charges differed considerably. Reductions of germ-counts after sterilization in the autoclave at 123,5 degrees C (fig. 1) and at 134 degrees C (fig 2), as well as with hot air at 120-125 degrees C (fig 3) and 133-138 degrees C (fig 4) demonstrate the heat-resistance. The individual biological indicators differ in killing-time and times of survival (table 2). Our tests demonstrate that only single biological indicators (table 4) will grant satisfying results in continuous checking of sterilization process.