Efficacy of Electrolyzed – Oxidizing Water for Inactivating Escherichia coli Inoculated on Holy Basil

Abstract

Electrolyzed – oxidizing (EO) water is a relatively new method that has been utilized for killing pathogens in agriculture, medical sterilization and food sanitation. This water is generated by passing sodium chloride solution through EO water generator. In this study, the EO water was used to
treat holy basil inoculated with Escherichia coli. The initial pH and oxidation – reduction potential (ORP) of EO water were 2.09 and 1200 mV, respectively. The treatments changed ORP to 800, 950 and 1100 mV. The contact times were 10, 30 and 60 min. In pure culture, E. coli viable counts in the sample treated with EO water were reduced to undetectable levels at all ORP and times. However no reduction in E. coli counts was achieved in the control sample (treated with deionized water). The initial population of E. coli was about 8.5 log₁₀ CFU / ml which was inoculated on 5 g of holy basil. Results showed that the treatment treated with EO water was reduced about 2 log₁₀ CFU / ml in ORP 800 and 950 mV, 4 log₁₀ CFU / ml in ORP 1100 mV for 10 min. When the contact time increased to 30 min, the reduction of E. coli count was about 3 log₁₀ CFU / ml in ORP 950 mV and 5 log₁₀ CFU / ml in ORP 1100 mV. But the reduction was not different from 10 min when treated with ORP 800 mV. When the contact time increased to 60 min, the reduction of E. coli count was about 3 log₁₀ CFU / ml in ORP 800 mV, 4 log₁₀ CFU / ml in ORP 950 mV. and 6 log₁₀ CFU / ml in ORP 1100 mV. These results could be concluded that the ORP of EO water and contact time significantly inactivated E. coli.