title: Evaluation of bactericidal activity of weakly acidic electrolyzed water (WAEW) against Vibrio vulnificus and Vibrio parahaemolyticus.
abstract: Vibrio parahaemolyticus and Vibriovulnificus cause severe foodborne illness in humans; thus, to reduce outbreaks of disease, it is clearly important to reduce food contamination by these pathogens. Although electrolyzed oxidizing (EO) water has been reported to exhibit strong bactericidal activities against many pathogens, it has never been tested against V. vulnificus and V. parahaemolyticus. The purpose of this study was to evaluate the bactericidal activity of weakly acidic electrolyzed water (WAEW), a type of EO water, against V. vulnificus and V. parahaemolyticus. Cell suspensions and cell cultures of both pathogens were treated for 30s with sodium hypochlorite solution containing 35mg/L available chlorine concentration (ACC) or WAEW containing 35mg/L ACC. After an initial inoculum of 5.7logCFU/mL, the number of viable V. vulnificus cells was reduced by 2.2 logs after treatment for 60s with sodium hypochlorite solution containing 35mg/L ACC, while no cells survived treatment with WAEW for 30s. Similar results were obtained for V. parahaemolyticus. Under open storage conditions, WAEW maintained bactericidal activities against cell suspensions of both strains after 5weeks but disappeared against cell cultures of the two strains after 5weeks. Under closed storage conditions, however, WAEW maintained bactericidal activities against both cell suspensions and cell cultures of each strain after 5weeks. No cells were detected in the cell suspensions and cultures when the ACC of WAEW was more than 20mg/L and treatment time was greater than 15s. Bactericidal activity of WAEW against V. vulnificus cell culture was reduced when the ACC of WAEW was less than 15mg/L but was maintained in the V. vulnificus cell suspension when the ACC of WAEW was 0.5mg/L. Thus, the bactericidal activity of WAEW was primarily affected by ACC rather than treatment time. Similar results were obtained for V. parahaemolyticus, indicating that WAEW kills these microorganisms more quickly than a chemical product such as sodium hypochlorite (NaClO), even at equivalent ACCs.
authors.affiliation: Faculty of Marine Bioscience & Technology, Gangneung-Wonju National University, 120 Gangnung daehangno, Gangnung city, Gangwon 210-702, Republic of Korea.
authors.forename: Yaru
authors.initials: Y
authors.lastname: Quan
authors.forename: Kyoo-Duck
authors.initials: KD
authors.lastname: Choi
authors.forename: Donghwa
authors.initials: D
authors.lastname: Chung
authors.forename: Il-Shik
authors.initials: IS
authors.lastname: Shin
mesh_terms: D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004203:Disinfection / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004572:Electrolysis; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D012758:Shellfish / Q000382:microbiology*; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013997:Time Factors; D014736:Vibrio parahaemolyticus / Q000187:drug effects / Q000254:growth & development*; D041261:Vibrio vulnificus / Q000187:drug effects / Q000254:growth & development*; D014867:Water / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D014867:Water; D012973:Sodium Hypochlorite