Study of plasma-induced inactivation of a reference micro-organism

We present a result of an ongoing European initiative (European COST Action MP 1101) that aims to create a reference plasma system and a biological reference protocol for the study and comparison of plasma treatments across laboratories. Endospores of Bacillus subtilis ATCC 6633 are proposed as reference microorganism as they can be stored for long periods without loss of viability, serving as a common starting point for experiments performed in different locations and at different times. To avoid problems related to shadowing effects, a monolayer of spores are deposited onto filter membranes using a vacuum filtration technique and these are then exposed to different plasma systems. In this study, sample preparation protocols and bactericidal properties of a dielectric-barrier surface discharge are reported upon.