Bactericidal Activity of Slightly Acidic Electrolyzed Water Produced by Different Methods Analyzed with Ultraviolet Spectrophotometric

Abstract

Abstract Slightly acidic electrolyzed water (SAEW) as a novel antimicrobial agent is generated by electrolysis of dilute hydrochloric acid (HCl) and/or sodium chloride (NaCl) solution in a cell with or without a separating membrane. The ultraviolet absorption spectra were used to determine the concentration of hypochlorous acid (HClO) and hypochlorite ion (ClO–) in SAEW generated by four different methods and their bactericidal efficiency for inactivation of Escherichia coli O157:H7 and Salmonella enteritidis was evaluated. During the production of equivalent available chlorine in SAEW, more HClO was produced by electrolysis of HCl solution in a non-membrane generator and mixing the acid and alkaline electrolyzed water generated in a generator with membrane, compared with the methods of adding HCl to neutral electrolyzed water (NEW) and electrolyzing the mixture of NaCl and HCl solution in a non-membrane cell. At the 10 mg/L available chlorine concentration, SAEW produced by the methods with more HClO generation had significantly higher (p<0.05) bactericidal efficiency for inactivation of both pathogens.