Bactericidal Activities of Several Electrolyzed Waters

Abstract

Bactericidal activities of several electrolyzed waters were evaluated by time-kill assay using Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Strongly acidic electrolyzed oxidizing water (EOW) showed remarkably high bactericidal activity against all four bacterial strains, including a spore-forming bacterium, B. subtilis. Strongly alkaline electrolyzed reducing water (ERW) exhibited high bactericidal activity against gram-negative bacteria (E. coli and P. aeruginosa), whereas it showed low or no bactericidal activity against gram-positive bacteria. In contrast, hydrogen water (HW) showed only low bactericidal activity against two (S. aureus and P. aeruginosa) of the four strains tested, and weak acidic electrolyzed reducing water (WA-ERW) did not show any bactericidal activity. Thus, it was demonstrated that among several electrolyzed waters, EOW possessed high bactericidal activity against all four bacterial strains regardless of gram-negative or gram-positive status and against their spore formation. It was also suggested that some electrolyzed waters might be applicable as disinfectants or antiseptic agents instead of normal purified water in pharmaceutical preparations or cosmetics.