Novel sterilization method of Bacillus atrophaeus and Geobacillus stearothermophilus spores by low concentration chlorine dioxide gas

Abstract

Abstract: Chlorine dioxide (ClO₂) is a powerful disinfectant widely regarded as a safe and effective hygienic agent in pharmaceutical plants and other manufacturing facilities that require sterility. However, the efficacy of low concentrations of ClO₂ gas on sterilizing spore-forming bacteria remains uncertain. In this study, we investigated the optimal conditions for disinfection of spore-forming bacteria with low concentrations of ClO₂ gas using biological indicators. The results showed that 0.05 ppmv (0.13 mg/m³) ClO₂ gas at 37±1℃, 86±2%RH sterilized Bacillus atrophaeus in 14 d and Geobacillus stearothermophilus in 28 d (>6 log₁₀ reductions）. Based on these results, we propose that low concentrations of ClO₂ gas are useful for controlling contamination by spore-forming bacteria in aseptic facilities.