Effectiveness of low concentration electrolyzed water to inactivate foodborne pathogens under different environmental conditions

Strong acid electrolyzed water (SAEW) has a very limited application due to its low pH value (<2.7) and corrosive characteristics. Thus, we developed new low concentration electrolyzed water (LcEW). The efficacy of LcEW under various treatment conditions for the inactivation of different foodborne pathogens in pure culture was evaluated and compared with SAEW. The efficiency of LcEW and SAEW for the inactivation of predominant foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus and Salmonella Typhimurium) with different dipping times (1, 3, 5, 7 and 10 min), pH values (2.5, 4.0, 5.0, 6.0 and 9.0) and temperatures (4, 15, 23, 35 and 50 degrees C) were determined. Reductions of bacterial populations of 1.7 to 6.6 log(10) CFU/mL in various treated conditions in cell suspensions were observed after treatment with LcEW and SAEW, compared to the untreated control. Dip washing (1 min at 35 degrees C) of lettuce leaves in both electrolyzed water resulted in 2.5 to 4.0 log(10) CFU/g compared to the unwashed control. Strong inactivation effects were observed in LcEW, and no significant difference (p>0.05) was observed between LcEW and SAEW. The effective form of chlorine compounds in LcEW was almost exclusively hypochlorous acid (HOCl), which has strong antimicrobial activity and leaves no residuals due to the low concentration of residual chlorine. Thus, LcEW could be widely applied as a new sanitizer in the food industry.

Allergic potency of Japanese cedar pollen Cry j 1 is reduced by a low concentration of hypochlorous acid generated by electolysis

BACKGROUND

Although Japanese cedar (Cryptomeria japonica) pollinosis has developed into a health problem, few methods eradicate indoor allergens completely. In a recent study, however, the effectiveness of inactivation with sodium hypochlorite (NaOCl) treatment was revealed. Therefore, the present study aimed to elucidate the ability of chlorine bleach (NaOCl) to reduce the immunogenicity of the major allergenic protein of Japanese cedar (Cry j 1).

METHODS

Sodium dodecyl sulfate polyacrylamide gel electrophoresis, Western blotting, enzyme-linked immunosorbant assay, and skin testing were carried out in 7 individuals.

RESULTS

The allergenic protein was undetectable using sodium dodecyl sulfate polyacrylamide gel electrophoresis and silver staining at a sodium hypochlorite/allergenic protein molar ratio of 457. Western blotting with human sera showed the same dose-dependent efficacy. The immunogenicity of the purified protein and cedar pollen was also demonstrated on enzyme-linked immunosorbant assay to be reduced by sodium hypochlorite treatment in a dose- and time-dependent manner. Moreover, sodium hypochlorite-treatment inhibited the skin test response to the protein in all 7 individuals.

CONCLUSIONS

Hypochlorous acid generated by electrolysis is an effective method for significantly reducing the immunogenicity of Cry j 1.