Inactivation of Clostridium sporogenes and Geobacillus stearothermophilus spores with the use of microwave and steam sterilizers and microwave oven

Abstract

Introduction. Equipment for sterilization used in medical laboratories must be absolutely effective in eliminating microorganisms and their spores. It often directly influences human health, even life. The aim of the study was to compare the effectiveness of sterilization using the steam sterilizer ASV E, microwave sterilizer EnbioJet ML1, microwave sterilizer for baby bottles and breast pumps AVENT and microwave oven.

Materials and methods. Evaluation of the effectiveness of sterilization with the use of selected devices based on pressure-thermal and microwave-thermal methods was conducted, on the basis of elimination of G. stearothermophilus PCM 2104 and C. sporogenes IW 1306 spores.

Results. After using the steam sterilizer, 100% inactivation of spores of both species was noted. In the case of EnbioJet ML1 sterilizer, in the test containing 106 CFU × cm–3 G. stearothermophilus spores, 1.63 × 101 CFU × cm–3 survived. The baby bottles sterilizer proved less effective. While the microwave, in the case of tests with the highest spore content, provided their inactivation only at the level of more than 70.0%. The steam sterilizer and EnbioJet ML1 sterilizer were the most effective, whereas the latter ensured a very short time of high temperature effect, which has a favorable impact on the properties of sterilized products, for example compounds decomposing in high temperature.

Conclusion. Results of own, as well as other authors’ studies allow to confirm the large potential in the scope of using microwave radiation for the sterilization and disinfection of materials of various sensitivity to temperature.