Efficacy of homemade electrolyzed water disinfectant for inactivation of foodborne pathogens

Electrolyzed water, or hypochlorous acid, is a non-corrosive chlorinated disinfectant increasingly embraced by public and household consumers. This could be attributed to its effectiveness, economical, and ease of manufacturing. However, the antimicrobial efficacy of homemade EW (HEW) prepared using economical and easy-to-use EW generators has not been experimentally evaluated. The present study evaluated HEW solutions prepared and applied using different household generators and modes of application, respectively. HEW solutions were evaluated by spotting bacteria-inoculated agar, spraying bacteria-inoculated agar, and dipping/suspending bacteria into HEW solutions before colony-enumeration plating. Blood lysis/coagulation and total available chlorine concentration were investigated for bleach-equivalent toxicity using animal erythrocytes and free-chlorine-testing strips, respectively. The statistical significance of HEW antibacterial efficacy was determined using Student’s t-test (P<0.05). Qualitative antibacterial analysis of fresh HEW spots exhibited growth inhibition zones with reducing inhibition visibility as dilution increased. Viable-culture-count comparative analyses revealed that the dipping method posted more antibacterial efficacy than spraying (≥~5-log vs.≤~3-log cfu/mL, P<0.05), suggesting that the dipping method be used for subsequent investigations. Dosage and shelf-life analyses demonstrated that HEW efficacy could increase and reduce significantly with dilutions (≥1/8 v/v) and time, respectively, and was completely abolished at dilutions≥1/16 (v/v). There was a significant HEW efficacy difference (P<0.05) among different generators. Comparative toxicity assays revealed that HEW (≤1-month-old), unlike bleach, possessed much lesser total chlorine (>1000X) and did not cause blood complications. The findings suggest the effectiveness, friendliness, and optimization conditions of HEW and that its production needs a standardized evaluation.