Browsing by Author "Kamitani, Y"

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    Antimicrobial effect of slightly acidic electrolyzed water for inactivation of Salmonella spp. and Escherichia coli on fresh strawberries (Fragaria L.)
    (2010-10-18) Issa-Zacharia, A; Kamitani, Y; Muhimbula, H; Iwasaki, K
    Antimicrobial effect of slightly acidic electrolyzed water (SAEW: pH 5.6 ± 0.1, 20.5 ± 1.3 mg/L available chlorine concentration; ACC) against indigenous aerobic mesophiles and inoculated Escherichia coli and Salmonella spp. on fresh strawberry was assessed. The antimicrobial effect of SAEW was compared with that of strong acidic electrolyzed water (StAEW) and sodium hypochlorite (NaOCl) solution. SAEW effectively reduced total aerobic mesophilic bacteria from strawberries by 1.68 log10CFU/g and was not significantly different from that of NaOCl solution (p > 0.05). Antimicrobial effect of SAEW against Salmonella spp. and E. coli was indicated by a more than 2 log10CFU/g reduction of their population and the effect was not significantly different from that of NaOCl solution and StAEW at similar treatment conditions (p > 0.05). From these findings, SAEW with a near-neutral pH and low available chlorine concentration exhibits an equivalent bactericidal effectiveness to NaOCl solution and thus SAEW is a potential sanitizer that would be used as an alternative for StAEW and NaOCl solution in the fresh fruit and vegetables industry.
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    Decontamination of ready-to-eat Japanese mustard green (Brassica japonica) from Escherichia coli using slightly acidic electrolyzed water
    (2009-09-02) Issa-Zacharia, A; Kamitani, Y; Kazuo Morita, K; Iwasaki, K
    In the present study, slightly acidic electrolyzed water (SAEW: pH 5.6 ± 0.21, 22 ± 1.4 mg/L available chlorine concentration; ACC) was evaluated for decontamination of Japanese mustard green (Brassica japonica) from Escherichia coli (E. coli) and its effectiveness was compared to that of sodium hypochlorite solution (NaOCl solution: pH 9.8±0.01, 110 ± 2.3 mg/L ACC). Decontamination of Japanese mustard green inoculated with E. coli was done by dipping samples into SAEW, NaOCl solution and Tap water (control) with stirring for 2, 5, 10 and 15 min. SAEW achieved E. coli reduction of 1.29 -1.64 log10 CFU/g and was not significantly different from that achieved by NaOCl solution (P > 0.05). Increasing the exposure time did not significantly affect its decontamination effectiveness. The results of current study indicate that SAEW with near neutral pH and low available chlorine concentration could be used as an alternative food sanitizer for NaOCl solution to reduce the population of pathogens from the fruits and vegetables in food industry.
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    In vitro inactivation of Escherichia coli, Staphylococcus aureus and Salmonella spp. using slightly acidic electrolyzed water
    (The Society for Biotechnology, 2010) Issa-Zacharia, A.; Kamitani, Y; Tiisekwa, A.; Morita, K.; Iwasaki, K.
    In the current study, the effectiveness of slightly acidic electrolyzed water (SAEW) on an in vitro inactivation of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Salmonella spp. was evaluated and compared with other sanitizers. SAEW (pH 5.6, 23 mg/l available chlorine concentration; ACC; and 940 mV oxidation reduction potential; ORP) was generated by electrolysis of dilute solution of HCl (2%) in a chamber of a non-membrane electrolytic cell. One milliliter of bacteria suspension (ca. 10–11 log 10 CFU/ml) was mixed with 9 ml of SAEW, strong acidic electrolyzed water (StAEW; ca. 50 mg/l ACC), sodium hypochlorite solution (NaOCl; ca.120 mg/l ACC) and distilled water (DW) as control and treated for 60 s. SAEW effectively reduced the population of E. coli, S. aureus and Salmonella spp. by 5.1, 4.8, and 5.2 log 10 CFU/ml. Although, ACC of SAEW was more than 5 times lower than that of NaOCl solution, they showed no significant bactericidal difference (p N 0.05). However, the bactericidal effect of StAEW was significantly higher (p b 0.05) than SAEW and NaOCl solution in all cases. When tested with each individual test solution, E. coli, S. aureus and Salmonella spp. reductions were not significantly different (p N 0.05). These findings indicate that SAEW with low available chlorine concentration can equally inactivate E. coli, S. aureus and Salmonella spp. as NaOCl solution and therefore SAEW shows a high potential of application in agriculture and food industry as an environmentally friendly disinfection agent.