Evaluation of the antimicrobial efficacy of neutral electrolyzed water on pork products and the formation of viable but nonculturable (VBNC) pathogens

Detection and Verification of the Viable but Nonculturable (VBNC) State of Escherichia coli O157:H7 and Listeria monocytogenes Using Flow Cytometry and Standard Plating

“…Our findings however depart from the findings by Zhang, Chen, Xia, Li, and Hung (2018) who observed E. coli O157:H7 entering the VBNC state at FCC levels of 30 and 40 mg/L for acidic EO water and slightly acidic EO water. Han, Hung, and Wang (2018) also observed VBNC E. coli cells after treatment with neutral pH EO water at levels between 0.7 and 18.5 mg/L. In this study, VBNC cells were not detected between 5 and 20 mg/L FCC of EO water, contrasting the above-mentioned findings.…”

“…The studies by Han et al. () and Zhang et al. () used inoculum to EO water ratios of 1:3 and 1:9, respectively, while our study used a ratio of 2:3.…”

“…population of E. coli O157:H7 and the differences in the inoculum to EO water ratios used. The studies by Han et al (2018) and Zhang et al (2018) used inoculum to EO water ratios of 1:3 and 1:9, respectively, while our study used a ratio of 2:3. The aforementioned studies also used pathogens at an initial population of 8 log CFU/mL while our study used cultures at approximately 6 log CFU/mL.…”

Formation of Sublethally Injured Yersinia enterocolitica, Escherichia coli O157:H7, and Salmonella enterica Serovar Enteritidis Cells after Neutral Electrolyzed Oxidizing Water Treatments

“…While such a low chlorination level caused the reduced metabolic activity of E. coli, it, on the other hand, enhanced the persistence of E. coli to nine antibiotics, including ampicillin, gentamicin, polymyxin, ciprofloxacin, terramycin, tetracycline, rifampin, clarithromycin, and chloromycetin (21). Similarly, the formation of VBNC cells was also found in this research group's previous study (12). When E. coli O157:H7, Salmonella enterica serovar Enteritidis, and Yersinia enterocolitica were treated with diluted NEO water (1%, 3%, 6%, 10%, 15%, and 25%), the formation of VBNC cells was confirmed using flow cytometry (12).…”

“…In addition, its neutral pH enables reduced chlorine loss and an extended shelf-life (2)(3)(4). Food products on which the antimicrobial efficacy of NEO water has been tested include tomatoes (5,6), romaine and iceberg lettuce (7), shredded carrots and spinach (8), fresh-cut endive, corn salad, "Four Seasons" salad (2), dates (9), blueberries (10), apples (11), and pork chops and pork skin products (12). NEO water treatments have also been applied to the surfaces of plastic and wooden cutting boards (13), bamboo board (14), and plates, spoons, forks, knives, and drinking glasses (15).…”