[The stability of biological indicators used for monitoring ethylene oxide gas sterilization].

It was found the correlation between the storage time of biological indicators and their usefulness for monitoring of gas sterilization with ethylene oxide (EO). Bacillus subtilis var niger ATTC 9372 was used as a test organism. Two kinds of investigations were done: observation of bacterial growing or lack of growing after 1 hour exposition of storage tests in EO (EO concentration- 750 mg/l, temperature +/- 50 degrees C, (humidity-40%) and examination of drop in number of spores on strip tests after storage time. The results show that sterilization efficacy may be monitored using such spore strip tests up to six months of storage.