Antimicrobial Efficacy of Electrolyzed Waters and Chlorine-Based Disinfectants: The Role of pH, Free Chlorine, and Oxidation–Reduction Potential Over Time

This study evaluated the antimicrobial efficacy of electrolyzed water (EW) and chlorine-based disinfectant (CLD) over time, focusing on the impact of pH, free chlorine (FCL), and oxidation-reduction potential (ORP). EW and CLD are commonly used for wound care and surgical instrument disinfection, but their chemical instability limits their use. The study was conducted in the Microbiology Laboratory of the University of Guanajuato, using <i>Escherichia coli</i> ATCC 25922 as the test organism. Disinfectants were maintained at 40°C, with systematic monitoring of pH, FCL, and ORP. Minimum bactericidal concentration was used to assess antimicrobial activity before and after thermal exposure. Statistical analyses included Kruskal-Wallis one-way ANOVA, and the Friedman test. Results showed that the antimicrobial activity of EW depended on FCL concentration, with a significant correlation between the absence of FCL and increased minimum bactericidal concentration (<i>p</i> < 0.01). Disinfectants with alkaline pH demonstrated greater stability over time (<i>p</i> < 0.01). The findings highlight the importance of FCL, pH, and ORP in the effectiveness of these disinfectants and underscore their limitations due to chemical instability in clinical settings.