Effect of Concentration of Hydrogen Peroxide Produced During Cold Plasma Treatment of Water on Inactivation Escherichia coli

Inactivation of microorganisms by plasma is a new technique in food science and biotechnology fields. This technique could be used to inactivate microorganisms in water. Reactive species such as UV, H2O2, O3, O, OH and intense electric field produced during plasma discharge, are known to be main factors of microorganisms inactivation.
In this study an electrical spark discharge system have been used to evaluate the ability of cold plasma to inactivate microorganisms. E. coli have been inoculated to water samples and after plasma treatment with various time laps, samples were collected to operate plate count tests. Beside microbiological tests, the concentration of Hydrogen Peroxide have been analyzed.
the results of this study showed that plasma can significantly inactivate high concentrations of bacteria in water. After plasma treatment of water samples for even short times, 8 Log CFU/ml reduction of bacteria population was observed. Observations showed that the concentration of Hydrogen Peroxide increased by 100 mg/l after plasma treatment.
In this study, electrical spark discharge cold plasma on water surface proved to have the ability of inactivating inoculated bacteria to water samples. According to our observations, the concentration of Hydrogen Peroxide have increased by treatment time and could be the main factor of microorganism inactivation in water by cold plasma treatment.