Low pressure plasma inactivation of Bacillus subtilis spores: insights into the mechanisms of spore resistance

Abstract

Being the most resistant form of a biological system, spores of Bacillus subtilis are very resistant against a broad spectrum of sterilization methods and, therefore, are commonly used as a biological indicator in order to verify the functionality of a sterilization procedure. The process of low-pressure plasma sterilization is a promising alternative to conventional sterilization methods as it is extremely fast, efficient and gentle to heat-sensitive materials. Active plasma species contain a high degree of sporicidal UV/VUV-radiation, as well as charged particles and free radicals, which exert detrimental effects on microorganisms. In this study we present novel insights into the key factors involved in spore inactivation by low pressure plasma sterilization using a double inductively-coupled plasma reactor.