Low Temperature Plasma by Corona discharge in water: lethal effect on Escherichia coli and Salmonella enterica serotype Typhimurium

Abstract

In this research work, inactivation of two significant global contributors to microbiological problems in water was carried out: Escherichia coli and Salmonella enterica serotype Typhimurium. Both are representative of fecal pollution and their presence could compromise water quality and food safety generating serious effects on human health.Simultaneous inactivation process of Escherichia coli and Salmonella enterica serotype Typhimurium involved the production of Low Temperature Plasma from Positive Corona discharge (20 kV, 0.45 mA) at atmospheric conditions. Initial bacteria concentrations in water were respectively, 3.4 log CFU/ml and 3.6 log CFU/ml, which are typical from poultry activities.High effectiveness (> 99%) in the process was obtained at the end of 180 s and, total inactivation of Escherichia coli and Salmonella enterica serotype Typhimurium was achieved at 360 s. During treatment, Escherichia coli bacteria showed major resistance to be reduced; nevertheless, synergistic lethal effects generated in water during the production of plasma: reactive chemical species, shock waves and UV radiation, allowed to get null bacteria survival.