Antimicrobial Effect of Electrolyzed Oxidizing Water against Escherichia coli O157:H7 and Listeria monocytogenes on Fresh Strawberries (Fragaria×ananassa)

Abstract

Antibacterial activity of electrolyzed oxidizing (EO) water prepared from 0.05% or 0.10% (w/v) sodium chloride (NaCl) solutions against indigenous bacteria associated with fresh strawberries (Fragaria x ananassa) was evaluated. The efficacy of EO water and sodium hypochlorite (NaOCl) solution in eliminating and controlling the growth of Listeria monocytogenes and Escherichia coli O157:H7 inoculated onto strawberries stored at 4 +/- 1 degrees C up to 15 d was investigated at exposure time of 1, 5, or 10 min. Posttreatment neutralization of fruit surfaces was also determined. More than 2 log(10) CFU/g reductions of aerobic mesophiles were obtained in fruits washed for 10 or 15 min in EO water prepared from 0.10% (w/v) NaCl solution. Bactericidal activity of the disinfectants against L. monocytogenes and E. coli O157:H7 was not affected by posttreatment neutralization, and increasing exposure time did not significantly increase the antibacterial efficacy against both pathogens. While washing fruit surfaces with distilled water resulted in 1.90 and 1.27 log(10) CFU/mL of rinse fluid reduction of L. monocytogenes and E. coli O157:H7, respectively, >/= 2.60 log(10) CFU/mL of rinse fluid reduction of L. monocytogenes and up to 2.35 and 3.12 log(10) CFU/mL of rinse fluid reduction of E. coli O157:H7 were observed on fruit surfaces washed with EO water and NaOCl solution, respectively. Listeria monocytogenes and E. coli O157:H7 populations decreased over storage regardless of prior treatment. However, EO water and aqueous NaOCl did not show higher antimicrobial potential than water treatment during refrigeration storage.

Reduction of Listeria monocytogenes contamination on produce – A quantitative analysis of common liquid fresh produce wash compounds

“…Some physical control measures including irradiation or pulsed UV light as well as certain biological means of control such as the use of bacteriophages or biocontrol agents have achieved reductions in experimental studies using L. monocytogenes (or other bacteria that may e6 log 10 cfu (Akbas & Olmez, 2007;Baert et al, 2009;Bari, Inatsu, Kawasaki, Nazuka, & Isshiki, 2002;Bari et al, 2003;Beuchat et al, 2004;Beuchat & Brackett, 1990;Beuchat et al, 1998;Burnett et al, 2004;Delaquis, Stewart, Cazaux, & Toivonen, 2002;Deza et al, 2003;Francis & O'Beirne, 2002;Hellstrom et al, 2006;Lang et al, 2004aLang et al, , 2004bLee, Yun, Fellman, & Kang, 2002;Li, Brackett, Chen, & Beuchat, 2002;Rodgers et al, 2004;Ruiz-Cruz et al, 2007;Stopforth et al, 2008;Su & D'Souza, 2012;Szabo, Simons, Coventry, & Cole, 2003;Udompijitkul et al, 2007;Walter et al, 2009;Wei et al, 2005;Zhang & Farber, 1996) Potassium hypochlorite is exempted from the requirement of a tolerance in or on all commodities (40 CFR 180.1300) Calcium hypochlorite is exempt from the requirement of a tolerance when used preharvest or postharvest in solution on all raw agricultural commodities and on grape when used as a fumigant postharvest by means of a chlorine generator pad (40 CFR 180.1054) Sodium hypochlorite is exempted from the requirement of a tolerance for residues and when used in accordance with good agricultural practices as a seed-soak treatment in the growing of the raw agricultural commodities vegetables, brassica, leafy , group 5 and radish, roots and radish, tops (40 CFR 180.1235;40 CFR 180.1070) Not all substances with chlorine are authorized as antimicrobials in the U.S. Calcium hypochlorite is authorized as food contact substance for use as an antimicrobial agent in water used to process fruits, vegetables, nuts, meat, and poultry and in pretreatment of water used in the manufacture of beverages...…”

“…aBeuchat & Brackett, 1990;Beuchat et al, 1998;Burnett et al, 2004;Choi et al, 2012;Deza et al, 2003;Han et al, 2001;Hellstrom et al, 2006;Jin & Lee, 2007;Kim et al, 2008;Kim et al, 2009a;Kim et al, 2009b;Lang et al, 2004a;Lang et al, 2004b;Lee et al, 2002;Lin, Moon, Doyle, &, McWatters, 2002;Park, Hung, Doyle, Ezeike, & Kim, 2001;Park et al, 2011;Rodgers et al, 2004;Sagong et al, 2011;Stopforth et al, 2008;Su & D'Souza, 2012;Udompijitkul et al, 2007;Venkitanarayanan et al, 2002;Wade, et al, 2003;Wu & Kim, 2007).…”

Salmonella and Tomatoes

“…It is approved for use in the United States as a wash-water additive for the produce industry ). Chlorine washes have been applied at various concentrations (20 to 300 ppm) to strawberries, blueberries, and raspberries inoculated with several different types of viruses and bacteria (Butot et al, 2008;Gulati et al, 2001;Udompijitkul et al, 2007;Wei et al, 2007). Chlorine washes of berries have generally yielded 1-to 2-log unit reductions in bacteria and viruses, although Pangloli and Hung (2013) reported a greater than 4-log 10 reduction of E. coli O157:H7 by chlorine (100 mg/L) on surface-contaminated blueberries.…”

“…Results are variable, with 1-to 4.4-log 10 cfu/g reductions reported (Gulati et al, 2001;Udompijitkul et al, 2007;Table 14.1). Quality attributes were not the focus of these studies, but it was noted that hydrogen peroxide caused slight discoloration of strawberries .…”

Efficacy of electrolyzed oxidizing water against Listeria monocytogenes and Morganella morganii on conveyor belt and raw fish surfaces

“…Electrolyzed oxidizing (EO) water was reported to exhibit antimicrobial activity against cell suspensions of several bacterial species and against food-borne pathogens attached to fruits and vegetables (Bari, Sabina, Isobe, Uemura, & Isshiki, 2003;Guentzel, Lamb, Callan, Emmons, & Dunhamb, 2008;Udompijitkul, Daeschel, & Zhao, 2007), eggs (Russell, 2003), tableware (Handojo, Lee, Hipp, & Pascall, 2009), cutting boards (Chiu, Duan, Liu, & Su, 2006, food processing equipment (Park, Hung, & Kim, 2002), food processing gloves and ceramic tile, floor tile, and stainless steel surfaces Phuvasate & Su, 2010). EO water was also found to be effective against pathogens associated with poultry processing (Hinton, Northcutt, Smith, Musgrove, & Ingram, 2007) but was ineffective in reducing pathogens on fresh pork (Fabrizio & Cutter, 2004) and RTE meats (Fabrizio & Cutter, 2005).…”