Dielectric barrier discharge (DBD) devices are known ozone generators. Authors have previously demonstrated a DBD surface plasma source, operating in air at atmospheric pressure, to achieve killing of vegetative cells in 2-3 min and sterilization in 20 min (bacterial spores). The aim of this paper is to examine the role of the ozone in surface DBD plasma sterilization. The role of ozone in plasma killing is examined by a) characterizing the rate of production/decay of ozone during DBD plasma generation, b) studying the effect of exposing bacteria (Escherichia coli) solely to the ozone thus produced. Our results indicate that while ozone plays a major role, the energy flux delivered to the electrodes is also crucial in the process of plasma sterilization.

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Cover: Dielectric Barrier Discharge (DBD) plasma devices are known ozone generators. The role of produced ozone in DBD sterilization was studied by examining its lethality to Escherichia coli. Measuring the levels of ozone produced during and after plasma generation identifies three phases: production, diffusion and decay. Each of these phases is characterized by an empirical formula. A correlation between the ozone production and the input energy flux to the plasma devices is also developed that is key to surface plasma sterilization. Further details can be found in the article by Subrata Roy et. al. http://doi.wiley.com/10.1002/ppap.201300108.