Elementor #3437

LWT-Food Science and Technology 79 (2017)

Efficacy of low concentration neutralised electrolysed water and ultrasound combination for inactivating Escherichia coli ATCC 25922, Pichia pastoris GS115 and Aureobasidium pullulans 2012 on stainless steel coupons

The sanitising effect of low concentration neutralised electrolysed water (LCNEW, pH: 7.0, free available chlorine (FAC): 4 mg/L) combined with ultrasound (37 kHz, 80 W) on food contact surface was evaluated. Stainless steel coupon was chosen as attachment surface for Escherichia coli ATCC 25922, Pichia pastoris GS115 and Aureobasidium pullulans 2012, representing bacteria, yeast and mold, respectively. The results showed that although LCNEW itself could effectively reduce survival population of E. coli ATCC 25922, P. pastoris GS115 and low concentration A. pullulans 2012 in planktonic status, LCNEW combined with ultrasound showed more sanitising efficacy for air-dried cells on coupons, with swift drops: 2.2 and 3.1 log CFU/coupon reductions within 0.2 min for E. coli ATCC 25922 and P. pastoris GS115, respectively and 1.0 log CFU/coupon reductions within 0.1 min for A. pullulans 2012. Air-dried cells after treatment were studied by atomic force microscopy (AFM)/optical microscopy (OM) and protein leakage analyses further. All three strains showed visible cell damage after LCNEW and LCNEW combined with ultrasound treatment and 1.41 and 1.73 μg/mL of protein leakage were observed for E. coli ATCC 25922 and P. pastoris GS115, respectively after 3 min combination treatment, while 6.22 μg/mL of protein leakage for A. pullulans 2012 after 2 min combination treatment. For biofilms, LCNEW combined with ultrasound also significantly reduced the survival cells both on coupons and in suspension for all three strains. The results suggest that LCNEW combined with ultrasound is a promising approach to sanitise food equipment.

Food Control 73 (2017)

Treatment with low-concentration acidic electrolysed water combined with mild heat to sanitise fresh organic broccoli (Brassica oleracea)

The effects of low-concentration electrolysed water (LcEW) (4 mg/L free available chlorine) combined with mild heat on the safety and quality of fresh organic broccoli (Brassica oleracea) were evaluated. Treatment with LcEW combined with mild heat (50 °C) achieved the highest reduction in naturally occurring microorganisms and pathogens, including inoculated Escherichia coli O157:H7 and Listeria monocytogenes (P < 0.05). In terms of the antioxidant content of the treated broccoli, the total phenolic levels and ferric reducing antioxidant power remained unchanged; however, the oxygen radical absorbance capacity of the treated broccoli was higher than that of the untreated control. In addition, mild heat treatment resulted in an increase in firmness. The increased firmness was attributed to changes in the pectin structure, including the assembly and dynamics of pectin. The results revealed that mild heat induced an antiparallel orientation and spontaneous aggregation of the pectin chains. This study demonstrated that LcEW combined with mild heat treatment was effective to reduce microbial counts on fresh organic broccoli without compromising the product quality.

Journal of food science and technology 54.5 (2017)

Application of electrolysed oxidising water as a sanitiser to extend the shelf-life of seafood products

Electrolysed oxidising water (E.O. water) is produced by electrolysis of sodium chloride to yield primarily chlorine based oxidising products. At neutral pH this results in hypochlorous acid in the un-protonated form which has the greatest oxidising potential and ability to penetrate microbial cell walls to disrupt the cell membranes. E.O. water has been shown to be an effective method to reduce microbial contamination on food processing surfaces. The efficacy of E.O. water against pathogenic bacteria such as Listeria monocytogenes, Escherichia coli and Vibrio parahaemolyticus has also been extensively confirmed in growth studies of bacteria in culture where the sanitising agent can have direct contact with the bacteria. However it can only lower, but not eliminate, bacteria on processed seafoods. More research is required to understand and optimise the impacts of E.O. pre-treatment sanitation processes on subsequent microbial growth, shelf life, sensory and safety outcomes for packaged seafood products.

Food Control 63 (2016)

Reduction of Escherichia coli O157:H7 and Salmonella Typhimurium DT 104 on fresh produce using an automated washer with near neutral electrolyzed (NEO) water and ultrasound

Automated produce washers can be a useful processing aid when treating fresh produce contaminated with pathogens. The use of near neutral pH electrolyzed (NEO) water as a wash or sanitizing solution has been shown to lead to significant reductions of Escherichia coli O157:H7 and Salmonella on fresh produce. To further enhance reported pathogen reductions, the effects of a combined NEO water (155 mg/L free chlorine, pH 6.5) and ultrasound wash protocol on lettuce and tomatoes inoculated with E. coli O157:H7 and S. Typhimurium DT 104 were studied. The effects of the pH of NEO water and washer agitation on pathogen reductions were also assessed. Inoculated tomatoes and lettuce leaves were treated with either chilled deionized water or NEO water, with or without 20 kHz ultrasound (130 W and 210 W). Tomatoes were treated for 1, 3 and 5 min while lettuce was treated for 5, 10 and 15 min. Ultrasound significantly increased the oxidation-reduction potential (ORP) of NEO water (p < 0.05) but did not affect the pH and free chlorine concentration (p > 0.05). Increased washing time and higher ultrasonic power led to significantly greater reductions of both pathogens on produce items (p < 0.05). NEO water combined with 210 W ultrasonication for 15 min led to 4.4 and 4.3 log reductions of E. coli O157:H7 and S. Typhimurium on lettuce, respectively, while 210 W ultrasound for 5 min completely inactivated both pathogens on tomatoes. Both pathogens were completely inactivated in NEO water solutions, suggesting that its use presents little chance of cross-contamination

Foods 5.2 (2016)

Evaluation of Electrolytically-Generated Hypochlorous Acid (‘Electrolyzed Water’) for Sanitation of Meat and Meat-Contact Surfaces

Open AccessArticle Evaluation of Electrolytically-Generated Hypochlorous Acid (‘Electrolyzed Water’) for Sanitation of Meat and Meat-Contact Surfaces by Shawnna Veasey 1,2 andPeter M. Muriana 1,2,*OrcID 1 Department of Animal Science, Monroe Street, Oklahoma State University, Stillwater, OK 74078, USA 2 Robert M. Kerr Food & Agricultural Products Centre, 109 FAPC Building, Monroe Street, Oklahoma State University, Stillwater, OK 74078-6055, USA * Author to whom correspondence should be addressed. Academic Editor: Malik A. Hussain Foods 2016, 5(2), 42; https://doi.org/10.3390/foods5020042 Received: 13 April 2016 / Revised: 22 May 2016 / Accepted: 7 June 2016 / Published: 13 June 2016 (This article belongs to the Special Issue Microbial, Chemical and Physical Contamination of Food Products) Download PDF Browse Figures Citation Export Abstract ‘Electrolyzed water’ generators are readily available in the food industry as a renewable source of hypochlorous acid that eliminates the need for workers to handle hazardous hypochlorite concentrates. We applied electrolyzed water (EW) directly to multi-strain cocktails of Listeria monocytogenes, E. coli O157:H7, and Salmonella sp. at 250 ppm free available chlorine (FAC) and achieved greater than 6-log reductions in 2 min. Lower EW values were examined as antimicrobial interventions for fresh meat (beef carcasses), processed meats (frankfurters), and food contact surfaces (slicing blades). Little or no reduction relative to controls was observed when generic E. coli-inoculated beef carcasses or L. monocytogenes-inoculated frankfurters were showered with EW. Spray application of EW (25 and 250-ppm FAC) onto L. monocytogenes-inoculated slicing blades showed that greater reductions were obtained with ‘clean’ (3.6 and 5.7-log reduction) vs. ‘dirty’ (0.6 and 3.3-log reduction) slicing blades, respectively. Trials with L. monocytogenes-inoculated protein-EW solutions demonstrated that protein content as low as 0.1% is capable of eliminating FAC, reducing antimicrobial activity against L. monocytogenes. EW appears better positioned as a surface sanitizer with minimal organic material that can otherwise act as an effective reducing agent to the oxidizing solution rendering it ineffective.

International journal of food microbiology 231 (2016)

Effect of acidic electrolyzed water-induced bacterial inhibition and injury in live clam (Venerupis philippinarum) and mussel (Mytilus edulis)

The effect of acidic electrolyzed water (AEW) on inactivating Escherichia coli O104:H4, Listeria monocytogenes, Aeromonas hydrophila, Vibrio parahaemolyticus and Campylobacter jejuni in laboratory contaminated live clam (Venerupis philippinarum) and mussel (Mytilus edulis) was investigated. The initial levels of bacterial contamination were: in clam 4.9 to 5.7 log10 CFU/g, and in mussel 5.1 to 5.5 log10 CFU/g. Two types of AEW were used for treatment time intervals of 1 and 2 h: strong (SAEW) with an available chlorine concentration (ACC) of 20 mg/L, pH = 3.1, and an oxidation-reduction potential (ORP) of 1150 mV, and weak (WAEW) at ACC of 10 mg/L, pH = 3.55 and ORP of 950 mV. SAEW and WAEW exhibited significant inhibitory activity against inoculated bacteria in both shellfish species with significant differences compared to saline solutions treatments (1–2% NaCl) and untreated controls (0 h). SAEW showed the largest inhibitory activity, the extent of reduction (log10 CFU/g) ranged from 1.4–1.7 for E. coli O104:H4; 1.0–1.6 for L. monocytogenes; 1.3–1.6 for A. hydrophila; 1.0–1.5 for V. parahaemolyticus; and 1.5–2.2 for C. jejuni in both types of shellfish. In comparison, significantly (P < 0.05) lower inhibitory effect of WAEW was achieved compared to SAEW, where the extent of reduction (log10 CFU/g) ranged from 0.7–1.1 for E. coli O104:H4; 0.6–0.9 for L. monocytogenes; 0.6–1.3 for A. hydrophila; 0.7–1.3 for V. parahaemolyticus; and 0.8–1.9 for C. jejuni in both types of shellfish. Among all bacterial strains examined in this study, AEW induced less bacterial injury (~ 0.1–1.0 log10 CFU/g) and more inactivation effect. This study revealed that AEW (10–20 mg/L ACC) could be used to reduce bacterial contamination in live clam and mussel, which may help control possible unhygienic practices during production and processing of shellfish without apparent changes in the quality of the shellfish.

International Journal of Molecular Sciences 17.7 (2016)

Effectiveness of Hypochlorous Acid to Reduce the Biofilms on Titanium Alloy Surfaces in Vitro

Chemotherapeutic agents have been used as an adjunct to mechanical debridement for peri-implantitis treatment. The present in vitro study evaluated and compared the effectiveness of hypochlorous acid (HOCl), sodium hypochlorite (NaOCl), and chlorhexidine (CHX) at eliminating Gram-negative (E. coli and P. gingivalis) and Gram-positive (E. faecalis and S. sanguinis) bacteria. The effect of irrigating volume and exposure time on the antimicrobial efficacy of HOCl was evaluated, and a durability analysis was completed. Live/dead staining, morphology observation, alamarBlue assay, and lipopolysaccharide (LPS) detection were examined on grit-blasted and biofilm-contaminated titanium alloy discs after treatment with the three chemotherapeutic agents. The results indicated that HOCl exhibited better antibacterial efficacy with increasing irrigating volumes. HOCl achieved greater antibacterial efficacy as treatment time was increased. A decrease in antimicrobial effectiveness was observed when HOCl was unsealed and left in contact with the air. All the irrigants showed antibacterial activity and killed the majority of bacteria on the titanium alloy surfaces of biofilm-contaminated implants. Moreover, HOCl significantly lowered the LPS concentration of P. gingivalis when compared with NaOCl and CHX. Thus, a HOCl antiseptic may be effective for cleaning biofilm-contaminated implant surfaces

Food Control 60 (2016)

Effects of bacterial concentrations and centrifugations on susceptibility of Bacillus subtilis vegetative cells and Escherichia coli O157:H7 to various electrolyzed oxidizing water treatments

This study discussed the effects of different bacterial concentrations and centrifugations on the antimicrobial efficacy of electrolyzed oxidizing (EO) water on Bacillus subtilis and Escherichia coli O157:H7. Overnight grown bacterial cultures were centrifuged 1 to 3 times and bacterial concentrations were adjusted to approximately 9 (high), 7 (medium), or 5 (low) log10 CFU/mL. Antimicrobial efficacy of acidic EO water (AEW) and neutral pH EO water (NEW) containing 0.25–30 mg/L available chlorine was determined. In order to ascertain the effects of AEW and NEW on targeted pathogens, cellular properties at bio-molecular levels were also studied. The results showed that the susceptibility of both pathogens decreased significantly with increasing bacterial concentrations. AEW with 10, 0.25 and 0.25 mg/L and NEW with 30, 0.5 and 0.25 mg/L available chlorine were needed for high, medium and low bacterial concentrations, respectively to non-detectable levels by direct plating for E. coli O157:H7. B. subtilis was found more resistant to both EO water treatments and only 4.1 and 3.8 log reductions were achieved for AEW and NEW containing 30 mg/L available chlorine. On the other hand, it was observed that as centrifugation time increased, both bacteria became significantly more sensitive to EO water treatments. When centrifugation period increased from 1 to 3 times, additional 2.67 and 3.38 log E. coli O157:H7 reductions were observed for AEW and NEW treatments, respectively. A similar trend was observed for B. subtilis. DNA and protein leakage increased when pathogens were treated by AEW and NEW with increasing available chlorine concentration, but decreased DNA and protein leakage were observed with increased centrifugation times. These results indicate that initial bacterial concentration and the centrifugation time are two important factors and should be carefully considered in chlorine-based antimicrobial efficacy testing.

Journal of Veterinary Medical Science 78.7 (2016)

Inactivation of bacteria on surfaces by sprayed slightly acidic hypochlorous acid water: in vitro experiments

The capacity of slightly acidic hypochlorous acid water (SAHW), in both liquid and spray form, to inactivate bacteria was evaluated as a potential candidate for biosecurity enhancement in poultry production. SAHW (containing 50 or 100 ppm chlorine, pH 6) was able to inactivate Escherichia coli and Salmonella Infantis in liquid to below detectable levels (≤2.6 log10 CFU/ml) within 5 sec of exposure. In addition, SAHW antibacterial capacity was evaluated by spraying it using a nebulizer into a box containing these bacteria, which were present on the surfaces of glass plates and rayon sheets. SAHW was able to inactivate both bacterial species on the glass plates (dry condition) and rayon sheets within 5 min spraying and 5 min contact times, with the exception of 50 ppm SAHW on the rayon sheets. Furthermore, a corrosivity test determined that SAHW does not corrode metallic objects, even at the longest exposure times (83 days). Our findings demonstrate that SAHW is a good candidate for biosecurity enhancement in the poultry industry. Spraying it on the surfaces of objects, eggshells, egg incubators and transport cages could reduce the chances of contamination and disease transmission. These results augment previous findings demonstrating the competence of SAHW as an anti-viral disinfectant.

Poultry science 94.11 (2015)

Poultry Science An official journal of the Poultry Science Association

Food and bioprocess technology 8.8 (2015)

Reduction of Escherichia coli and Vibrio parahaemolyticus Counts on Freshly Sliced Shad (Konosirus punctatus) by Combined Treatment of Slightly Acidic Electrolyzed Water and Ultrasound Using Response Surface Methodology

International journal of clinical and experimental medicine 8.7 (2015)

An ınvestigation into the in-vitro effectiveness of electrolyzed water against various microorganisms

The aim of this study was to investigate the in-vitro antimicrobial activity of usage and normal concentrations of electrolyzed water in hospital. In our study, the effects of different concentrations of electrolyzed water named Envirolyte® (Industries International Ltd., Estonia) on two gram positive, four gram negative standard strains and clinical isolates of four gram negative, two gram positive, one spore-forming bacillus and Myroides spp strains that lead to hospital infections were researched. The effects of different concentrations and different contact times of Envirolyte® electrolyzed water on cited strains were researched through method of qualitative suspension tests. Petri dishes fo bacteria have been incubated at 37°C 48 hours. Bactericidal disinfectant was interpreted to be effective at the end of the period due to the lack of growth. Solutions to which disinfectant were not added were prepared with an eye to control reproduction and controlcultures were made by using neutralizing agents. 1/1, 1/2, and 1/10 concentrations of Envirolyte® electrolyzed water were found to be effective on the bacteria that lead to hospital infections used during all test times. As a conclusion, based upon the results we acquired, it was observed that Envirolyte® electrolyzed water of 100% concentration would be convenient to be used for disinfection when diluted to a usage concentration of 1/10.

Polymers 7.12 (2015)

Physicochemical and Antibacterial Properties of Carrageenan and Gelatine Hydrosols and Hydrogels Incorporated with Acidic Electrolyzed Water

The article focuses on investigation of the effects of usage of acidic electrolyzed water (AEW) with different sodium chloride concentration (0.001%, 0.01%, and 0.1%) for the preparation of carrageenan and gelatine hydrosols and hydrogels. To determine physiochemical properties of hydrosols, the pH, oxidation-reduction potential (ORP), available chloride concentration (ACC) and rheological parameters such us gelation and flow temperatures were measured. The samples were also characterized using Fourier transform infrared spectroscopy (FT IR) and texture profile analysis (TPA). Additionally, the article contains an analysis of antibacterial activity of carrageenan and gelatine hydrosols incorporated with acidic electrolyzed water, against Staphylococcus aureus and Escherichia coli. The FT IR spectra demonstrated that the structure of gelatine and carrageenan are not significantly affected by electrolyzed NaCl solution components. Furthermore, TPA analysis showed that the use of AEW did not cause undesirable changes in hydrogels layer. The microbiological analysis confirmed inhibition of bacterial growth by hydrosols to about 2.10 log reduction. The results showed that the range of reduction of microorganisms depends on the type AEW used. This might be explained by the fact that the lowest pH and the highest ACC values of hydrosols were obtained for samples with the longest period of exposure to electrolysis (10 min) and the highest amount of NaCl (0.1% w/v). These results suggest that hydrogels and hydrosols incorporated with AEW may be used for food preservation.

Food Control 53 (2015)

Efficacy of acidic and alkaline electrolyzed water for inactivating Escherichia coli O104:H4, Listeria monocytogenes, Campylobacter jejuni, Aeromonas hydrophila, and Vibrio parahaemolyticus in cell suspensions

This study investigated the effect of electrolyzed water on pathogenic bacteria cell suspensions. Specifically, we evaluated the efficacy of strong and weak acidic electrolyzed waters (SACEW, WACEW) and strong and weak alkaline electrolyzed waters (SALEW, WALEW) on Vibrio parahaemolyticus, Listeria monocytogenes, Aeromonas hydrophila, Campylobacter jejuni, and Escherichia coli O104:H4 in suspensions of (107–109 CFU/mL) in 1% NaCl. SACEW and WACEW were applied at available chlorine concentrations (ACC) of 20 and 10 mg/mL, pH 3.1 and 3.55 and oxidation-reduction potentials (ORP) of 1150 and 950 mV, respectively. Results show that no viable cells were recovered for V. parahaemolyticus, L. monocytogenes, A. hydrophila, C. jejuni within 2 min at 20 °C. However, E. coli O104:H4 was significantly more resistant to ALEW compared to ACEW. Results also show that the bactericidal activity of SACEW (20 mg/mL ACC) was more effective than WACEW (10 mg/mL ACC) in terms of inactivating E. coli O104:H4. Alkaline-electrolyzed waters were found to reduce cell numbers by 1–3 log (P < 0.05). However, alkaline electrolyzed water was less effective (P < 0.05) than acidic electrolyzed treatment.

Food Science and Biotechnology 24.3 (2015)

Application of slightly acidic electrolyzed water and ultrasound for microbial decontamination of kashk

Application of slightly acidic electrolyzed water (SAEW) in combination with ultrasound for decontamination of kashk was investigated. SAEW had a pH of 5.3-5.5, an oxidation reduction potential of 545-600 mV, and an available chlorine concentration of 20-22 mg/L. Kashk is a dairy product with a unique aroma and a high nutritive value produced in Iran. A 2/1 SAEW/kashk ratio showed 1.42, 1.13, 1.24, and 1.37 log CFU/mL microbial reductions in Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Aspergillus fumigatus, respectively, at room temperature. A combination of SAEW treatment with ultrasound (SAEW+ultrasound) resulted in 1.87, 1.67, 1.71, and 1.91 log CFU/mL reductions in S. aureus, B. cereus, E. coli, and A. fumigatus, respectively. The developed hurdle approach can be a useful tool for sanitization of kashk and similar products. Application of SAEW+ultrasound in dairy microbial decontamination is first reported herein.

Journal of Food Science 80.8

Efficacy of Neutral pH Electrolyzed Water in Reducing Escherichia coli O157:H7 and Salmonella Typhimurium DT 104 on Fresh Produce Items using an Automated Washer at Simulated Food Service Conditions

The objective of this study was to determine the efficacy of neutral pH electrolyzed (NEO) water (155 mg/L free chlorine, pH 7.5) in reducing Escherichia coli O157:H7 and Salmonella Typhimurium DT 104 on romaine lettuce, iceberg lettuce, and tomatoes washed in an automated produce washer for different times and washing speeds. Tomatoes and lettuce leaves were spot inoculated with 100 μL of a 5 strain cocktail mixture of either pathogen and washed with 10 or 8 L of NEO water, respectively. Washing lettuce for 30 min at 65 rpm led to the greatest reductions, with 4.2 and 5.9 log CFU/g reductions achieved for E. coli O157:H7 and S. Typhimurium respectively on romaine, whereas iceberg lettuce reductions were 3.2 and 4.6 log CFU/g for E. coli O157:H7 and S. Typhimurium respectively. Washing tomatoes for 10 min at 65 rpm achieved reductions greater than 8 and 6 log CFU/tomato on S. Typhimurium and E. coli O157:H7 respectively. All pathogens were completely inactivated in NEO water wash solutions. No detrimental effects on the visual quality of the produce studied were observed under all treatment conditions. Results show the adoption of this washing procedure in food service operations could be useful in ensuring produce safety.

Food Control 47 (2015)

Combined effects of slightly acidic electrolyzed water and fumaric acid on the reduction of foodborne pathogens and shelf life extension of fresh pork

This study evaluated the efficacy of the individual treatments (slightly acidic electrolyzed water [SAcEW] or fumaric acid [FA]) and their combination to reduce Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus, and Salmonella Typhimurium in fresh pork as well as to study the shelf life and sensory quality (color, odor, and texture) of pork during storage at 4 and 10 °C. The inoculated pork samples (10 g) were dipped for 3 min in each treatment (tap water [TW], SAcEW, strong acidic electrolyzed water [StAEW], 0.5% FA, or SAcEW + 0.5% FA) with or without mild heat (40 °C). Decontamination of fresh pork with SAcEW +0.5% FA at 40 °C for 3 min showed greater bactericidal effect compared to other treatments, which significantly (P < 0.05) reduced E. coli O157:H7, L. monocytogenes, S. aureus, and S. Typhimurium by 2.59, 2.69, 2.38, and 2.99 log CFU/g, respectively. This combined treatment significantly (P < 0.05) yielded in a longer lag time of naturally occurring bacteria (TBC) on pork stored at 4 °C. This combined treatment also prolonged the shelf life of pork up to 6 days and 4–5 days when stored at 4 °C and 10 °C, respectively, compared to those of the untreated pork. The results suggest that the combined treatment of SAcEW + 0.5% FA has potential as a novel method to enhance the microbial safety and quality of fresh pork.

Food microbiology 46 (2015)

Cross-contamination of Escherichia coli O157:H7 is inhibited by electrolyzed water combined with salt under dynamic conditions of increasing organic matter

Slightly acid electrolyzed water (SAcEW) and ultrasound (US) treatment have emerged as an environmental-friendly antimicrobial agent. However, SAcEW treatment alone shows low antimicrobial efficiency. Therefore, the aim of this study was to develop a hurdle approach that combined SAcEW and US to improve the antimicrobial effect against Bacillus cereus as well as inhibition of the growth on potato. US treatment under different conditions of dip times, acoustic energy densities (AED) and temperatures were conducted to obtain the optimal condition. Our findings demonstrate that 3 min of US with 400 W/L of AED at 40 °C treatment (US + 40 °C) significantly (p ≤ 0.05) reduced B. cereus population by 2.3 ± 0.1 log CFU/g with minimal change in the color of potato. In addition, 3 min of SAcEW (pH, 5.3–5.5; ORP, 958–981 mV; ACC, 28–30 mg/L) simultaneous with US+40 °C treatment (SAcEW + US+40 °C) an approximately 3.0 log CFU/g reduction in B. cereus. Furthermore, SAcEW + US+40 °C treatment efficiently extended lag time of B. cereus by 0.2–10.5 hrs, reduced that of specific growth rate by 0.01–0.23 log CFU/h during storage at different temperatures from 5 to 35 °C. Therefore, this combined hurdle technology is capable of improving microbial safety of potato during storage and distribution.

Food Control 54 (2015)

The bactericidal activity of acidic electrolyzed oxidizing water against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on raw fish, chicken and beef surfaces

The bactericidal efficacy of acidic electrolyzed oxidizing water (AC-EW) (pH ¼ 2.30, free chlorine ¼ 38 ppm) and sterile distilled water (DW) on three pathogens (Escherichia coli O157:H7 Salmonella Typhimurium, and Listeria monocytogenes) inoculated on raw trout skin, chicken legs and beef meat surfaces was evaluated. The decontaminating effect of AC-EW and DW was tested for 0 (control), 1, 3, 5 and 10 min at 22 C. AC-EW significantly (P < 0.05) reduced the three pathogens in the inoculated samples compared to the control and DW. The level of reduction ranged between ca.1.5 e1.6 logs for E. coli O157:H7 and S. Typhimurium in the inoculated foods. However, AC-EW exhibited less bactericidal effect against L. monocytogenes (1.1e1.3 logs reduction). AC-EW elicited about 1.6e2.0 log reduction in the total mesophilic count. Similar treatment with DW reduced pathogens load by ca. 0.2e1.0 log reduction and total mesophiles by ca. 0.5e0.7 logs. No complete elimination of the three pathogens was obtained using AC-EW possibly because of the level of organic matter and blood moving from food samples to the AC-EW solution. This study demonstrates that AC-EW could considerably reduce common foodborne pathogens in fish, chicken and beef products.

Journal of Food Science 80.6 (2015)

Combined Effect of Thermosonication and Slightly Acidic Electrolyzed Water to Reduce Foodborne Pathogens and Spoilage Microorganisms on Fresh-cut Kale

This study evaluated the efficacy of individual treatments (thermosonication [TS+DW] and slightly acidic electrolyzed water [SAcEW]) and their combination on reducing Escherichia coli O157:H7, Listeria monocytogenes, and spoilage microorganisms (total bacterial counts [TBC], Enterobacteriaceae, Pseudomonas spp., and yeast and mold counts [YMC]) on fresh-cut kale. For comparison, the antimicrobial efficacies of sodium chlorite (SC; 100 mg/L) and sodium hypochlorite (SH; 100 mg/L) were also evaluated. Each 10 g sample of kale leaves was inoculated to contain approximately 6 log CFU/g of E. coli O157:H7 or L. monocytogenes. Each inoculated or uninoculated samples was then dip treated with deionized water (DW; control), TS+DW, and SAcEW at various treatment conditions (temperature, physicochemical properties, and time) to assess the efficacy of each individual treatment. The efficacy of TS+DW or SAcEW was enhanced at 40 °C for 3 min, with an acoustic energy density of 400 W/L for TS+DW and available chlorine concentration of 5 mg/L for SAcEW. At 40 °C for 3 min, combined treatment of thermosonication 400 W/L and SAcEW 5 mg/L (TS+SAcEW) was more effective in reducing microorganisms compared to the individual treatments (SAcEW, SC, SH, and TS+DW) and combined treatments (TS+SC and TS+SH), which significantly (P < 0.05) reduced E. coli O157:H7, L. monocytogenes, TBC, Enterobacteriaceae, Pseudomonas spp., and YMC by 3.32, 3.11, 3.97, 3.66, 3.62, and >3.24 log CFU/g, respectively. The results suggest that the combined treatment of TS+SAcEW has the potential as a decontamination process in fresh-cut industry.

International Journal of Food Microbiology 177 (2014)

Modeling growth of Escherichia coli O157:H7 in fresh-cut lettuce treated with neutral electrolyzed water and under modified atmosphere packaging

Journal of food protection 77.12 (2014)

Efficacy of Neutral Electrolyzed Water for Reducing Pathogenic Bacteria Contaminating Shrimp

Pathogenic contamination is a food safety concern. This study was conducted to investigate the efficacy of neutral electrolyzed water (NEW) in killing pathogens, namely, Vibrio parahaemolyticus, Vibrio vulnificus, Salmonella Enteritidis, and Escherichia coli in shrimp. Pure cultures of each pathogen were submerged separately in NEW containing five different chlorine concentrations: 10, 30, 50, 70, and 100 ppm. For each concentration, three submersion times were tested: 1, 3, and 5 min. The population of V. parahaemolyticus was rapidly reduced even at low concentrations, but prolonged contact times caused only a slight reduction. V. vulnificus was gradually inhibited with increasing NEW concentrations and contact times. For the V. parahaemolyticus applications of 70 ppm for 5 min and of 100 ppm for 3 min, each eliminated 7 log CFU/ml. For V. vulnificus, applications of 50 ppm for 3 min and 100 ppm for 1 min, each eliminated 7 log CFU/ml. Salmonella Enteritidis and E. coli were slightly reduced by NEW. Applications of 50 ppm for 15 min and 10 ppm for 30 min completely eliminated 4.16 log CFU/g of V. parahaemolyticus in inoculated shrimp, while only a 1-log CFU/g reduction of V. vulnificus was detected. Soaking shrimp in 10 ppm NEW for 30 min did not affect its sensory quality. Our results suggest NEW could be an alternative sanitizer to improve the microbiological quality of seafood.

Journal of Food Protection 77.1 (2014)

Growth Model of Escherichia coli O157:H7 at Various Storage Temperatures on Kale Treated by Thermosonication Combined with Slightly Acidic Electrolyzed Water

This study was conducted to investigate the disinfection efficacy of hurdle treatments (thermosonication plus slightly acidic electrolyzed water [SAcEW]) and to develop a model for describing the effect of storage temperatures (4, 10, 15, 20, 25, 30, and 35°C) on the growth of Escherichia coli O157:H7 on fresh-cut kale treated with or without (control) thermosonication combined with SAcEW. The hurdle treatments of thermosonication plus SAcEW had strong bactericidal effects against E. coli O157:H7 on kale, with approximately 3.3-log reductions. A modified Gompertz model was used to describe growth parameters such as specific growth rate (SGR) and lag time (LT) as a function of storage temperature, with high coefficients of determination (R2 > 0.98). SGR increased and LT declined with rising temperatures in all samples. A significant difference was found between the SGR values obtained from treated and untreated samples. Secondary models were established for SGR and LT to evaluate the effects of storage temperature on the growth kinetics of E. coli O157:H7 in treated and untreated kale. Statistical evaluation was carried out to validate the performance of the developed models, based on the additional experimental data not used for the model development. The validation step indicated that the overall predictions were inside the acceptable prediction zone and had lower standard errors, indicating that this new growth model can be used to assess the risk of E. coli O157:H7 contamination on kale.

Food Science and Technology Research 20.1 (2014)

Efficacy of Slightly Acidic Electrolyzed Water for Reduction of Foodborne Pathogens and Natural Microflora on Shell Eggs

The efficacy of slightly acidic electrolyzed water (SAEW) to inactivate foodborne pathogens and indigenous microbiota on shell eggs was evaluated and compared to chlorine dioxide (CD), acidic electrolyzed water (AEW) and NaClO solution. The eggs were artificially inoculated with S. enteritidis, E. coli O157:H7 and S. aureus and sprayed or immersed with SAEW, alkaline electrolyzed water (AlEW) followed by SAEW (AlEW+SAEW), CD, AEW and NaClO solution, respectively. The effect of SAEW on the natural microbiota of shell eggs was also determined. Spraying shell eggs with SAEW, CD and NaClO solution at an ACC of 60 mg/L had no significant bactericidal difference for foodborne pathogens and indigenous microbiota on shell eggs, and the difference of disinfection effect between SAEW and AEW was not significant, whereas the bactericidal activity of SAEW for E. coli O157:H7, S. aureus, total aerobic bacteria and moulds and yeasts was significantly higher than that of CD and NaClO solution at ACCs of 80 or 100 mg/L. SAEW was found to be more effective when used in conjunction with AlEW, and higher reductions were obtained with the immersion treatment. Results indicate that the disinfectant efficiency of SAEW is equivalent to or higher than that of chlorine dioxide and NaClO solution and therefore SAEW shows the potential to be used for sanitization of egg shells as an environmentally friendly disinfection agent.

Annals of Clinical Microbiology and Antimicrobials 13.1 (2014)

In vitro antimicrobial activity of Medilox® super-oxidized water

Aim Super-oxidized water is one of the broad spectrum disinfectants, which was introduced recently. There are many researches to find reliable chemicals which are effective, inexpensive, easy to obtain and use, and effective for disinfection of microorganisms leading hospital infections. Antimicrobial activity of super-oxidized water is promising. The aim of this study was to investigate the in-vitro antimicrobial activity of different concentrations of Medilox® super-oxidized water that is approved by the Food and Drug Administration (FDA) as high level disinfectant. Material and methods In this study, super-oxidized water obtained from Medilox® [Soosan E & C, Korea] device, which had been already installed in our hospital, was used. Antimicrobial activities of different concentrations of super-oxidized water (1/1, 1/2, 1/5, 1/10, 1/20, 1/50, 1/100) at different exposure times (1, 2, 5, 10, 30 min) against six ATCC strains, eight antibiotic resistant bacteria, yeasts and molds were evaluated using qualitative suspension test. Dey-Engley Neutralizing Broth [Sigma-Aldrich, USA] was used as neutralizing agent. Results Medilox® was found to be effective against all standard strains (Acinetobacter baumannii 19606, Escherichia coli 25922, Enterococcus faecalis 29212, Klebsiella pneumoniae 254988, Pseudomonas aeruginosa 27853, Staphylococcus aureus 29213), all clinical isolates (Acinetobacter baumannii, Escherichia coli, vancomycin-resistant Enterococcus faecium, Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, Bacillus subtilis, Myroides spp.), and all yeastsat 1/1 dilution in ≥ 1 minute. It was found to be effective on Aspergillus flavus at 1/1 dilution in ≥ 2 minutes and on certain molds in ≥ 5 minutes. Conclusion Medilox® super-oxidized water is a broad spectrum, on-site producible disinfectant, which is effective on bacteria and fungi and can be used for the control of nosocomial infection.

Poultry Science 93.9 (2014)

Poultry Science

Poultry Science® is now Gold Open Access (OA). The article processing charge (APC) APC for Poultry Science is $1500 for Poultry Science Association members, and $2000 for non-members per article, The APC will be billed after peer review and manuscript acceptance. For more information please also view the answers to frequently asked questions. First self-published in 1921, Poultry Science is an internationally renowned monthly journal, known as the authoritative source for a broad range of poultry information and high-caliber research. The journal plays a pivotal role in the dissemination of preeminent poultry-related knowledge across all disciplines. Poultry Science is an Open Access journal with no subscription charges, meaning authors who publish here can make their research immediately, permanently, and freely accessible worldwide while retaining copyright to their work. An international journal, Poultry Science publishes original papers, research notes, symposium papers, and reviews of basic science as applied to poultry. This authoritative source of poultry information is consistently ranked by Clarivate's Impact Factor as one of the top 10 agriculture, dairy and animal science journals to deliver high-caliber research. Currently it is the highest-ranked (by Impact Factor and Eigenfactor) journal dedicated to publishing poultry research. Subject areas include breeding, genetics, education, production, management, environment, health, behavior, welfare, immunology, molecular biology, metabolism, nutrition, physiology, reproduction, processing, and products.

Journal of applied microbiology 115.3 (2013)

Disinfection effectiveness of slightly acidic electrolysed water in swine barns

Aims To evaluate the disinfection effectiveness of slightly acidic electrolysed water (SAEW, pH 6·25–6·53), a new environmental friendly agent for inactivating micro-organisms adhered to the facility and aerosolized in the air of the swine barns and to explore the application of SAEW in livestock industries. Methods and Results Bacteria and fungi were isolated from the swine house air and treated by SAEW. The SAEW solution was flushed onto surfaces and sprayed within the whole swine barn. SAEW with an available chlorine concentration (ACC) of 300 mg l−1 can inhibit isolated microbes completely. The usage of SAEW (300 mg l−1) resulted in a significant (P < 0·05) reduction in microbes on the wall, rail and floor after flushing disinfection. Additionally, spraying SAEW at an ACC of 300 mg l−1 reduced 59% of the airborne organisms in 30 min and kept the population of microbes at a reduced level for at least 8 h. SAEW treatment also reduced pathogens on surfaces (P < 0·03) after spraying disinfection except on the surface of the wall. Conclusions SAEW may be a potential alternative disinfectant to reduce infections in swine barns. Significance and Impact of the Study The results of this study provide information on the antimicrobial efficiency of SAEW on the airborne bacteria and fungi in swine barns.

Journal of applied microbiology 115.3 (2013)

Preventing Salmonella Colonization of Chickens

Salmonella spp. may be found in the nest box of breeder chickens, cold egg-storage rooms at the farm, on the hatchery truck, or in the hatchery environment (5). These bacteria may then be spread to fertilized hatching eggs on the shell or, in some cases, may penetrate the shell and reside just beneath the surface of the eggshell. Research has demonstrated that contamination of raw poultry products with Salmonella spp. may be attributable to cross-contamination in the hatchery from Salmonella infected eggs or surfaces to uninfected baby chicks during the hatching process. Cox et al. (6 and 7) reported that broiler and breeder hatcheries were highly contaminated with Salmonella spp. Within the broiler hatchery, 71 percent of eggshell fragments, 80 percent of chick conveyor belts swabs, and 74 percent of pad samples placed under newly hatched chicks contained Salmonella spp. (6). Cason et al. (4) reported that, although fertile hatching eggs were contaminated with high levels of Salmonella typhimurium, they were still able to hatch. The authors stated that paratyphoid salmonellae do not cause adverse health affects to the developing and hatching chick. During the hatching process, Salmonella spp. is readily spread throughout the hatching cabinet due to rapid air movement by circulation fans. When eggs were inoculated with a marker strain of Salmonella during hatching, greater than 80 percent of the chicks in the trays above and below the inoculated eggs were contaminated (4). In an earlier study, Cason et al. (3) demonstrated that salmonellae on the exterior of eggs or in eggshell membranes could be transmitted to baby chicks during pipping.

The University of Georgia Cooperative Extension

Resistance of various shiga toxin-producing Escherichia coli to electrolyzed oxidizing water

The resistance of thirty two strains of Escherichia coli O157:H7 and six major serotypes of non-O157 shiga toxin-producing E. coli (STEC) plus E. coli O104:H4 was tested against electrolyzed oxidizing (EO) water using two different methods; modified AOAC 955.16 sequential inoculation method and minimum inhibitory concentration (MIC). In sequential inoculation method efficacy of sodium hypochlorite was also compared with equal free chlorine (45 mg/L) containing EO water. MIC experiments were conducted for 15 s testing period with free chlorine concentrations of 3.00, 2.50, 2.00, 1.50, 1.00, 0.50 and 0.25 mg/L. The individual strain resistance when tested using the sequential inoculation method was in between 5 and 10 positive tubes, where greater numbers of positive tubes indicate increased resistance of the respective strain to the particular sanitizer. The MIC of individual strains ranged from 0.50 to 1.50 mg/L free chlorine of EO water. In comparison to sodium hypochlorite at same free chlorine concentration EO water was more effective against all STEC cocktails tested. The resistance of STEC cocktails using sequential inoculation method was determined as E. coli O157 ≥ O103 ≥ O26 ≥ 0111 ≥ O121 ≥ 045 > O145. The similar pattern of resistance was observed when cocktails were subjected to MIC. The results indicate that different strains of same serotype can differ in their resistance toward an intervention. In addition, EO water treatment that reduces E. coli O157:H7 can equally if not more effectively reduce other non-O157 STEC tested.

Food Control 30.2 (2013)

Resistance of various shiga toxin-producing Escherichia coli to electrolyzed oxidizing water

Food Science and Biotechnology 22.1 (2013)

Ultrasonication Enhanced Low Concentration Electrolyzed Water Efficacy on Bacteria Inactivation and Shelf Life Extension on Lettuce

Abstract Effect of ultrasonication (40 kHz) to enhance low concentration electrolyzed water (LcEW) efficacy for microbial decontamination on lettuce leaves was investigated. Lettuce was separately treated with LcEW, ultrasonication, LcEW combined with ultrasonication, LcEW followed by ultrasonication, and ultrasonication followed by LcEW for 1, 3, and 5 min for each step at room temperature. The highest reduction (2.3 log CFU/g) in total bacteria count (TBC) was resulted from ultrasonication followed by LcEW. Subsequently, the effect of temperature was studied resulting in 2.6 and 3.18 log CFU/g reduction of TBC and Escherichia coli O157:H7 respectively, in 3 min ultrasonication followed by 3 min LcEW treatment at 40ºC. This optimum treatment also prevented lettuce from reaching 7.0 log CFU/g in TBC until the end of the 6 day storage at 10ºC. Therefore, this newly developed approach may result in improved microbiological safety and enhanced shelf life of produce.

Food Control 29.1 (2013)

Operating conditions for the electrolytic disinfection of process wash water from the fresh-cut industry contaminated with E. coli o157:H7

Food Control 30.1 (2013)

Effects of water hardness and pH on efficacy of chlorine-based sanitizers for inactivating Escherichia coli O157:H7 and Listeria monocytogenes

The effects of hardness and pH of water used to prepare electrolyzed oxidizing (EO) water and bleach solutions on the bactericidal activity of sanitizer prepared from the water were examined. EO water and bleach solutions were prepared with hard water of 0, 50, 100, and 200 mg/l as CaCO3 at pH 5, 6, 7, and 8. Increased water hardness tended to increase free chlorine and oxidation–reduction potential (ORP) and decrease pH of EO water. Chlorine levels also increased with water pH. Water hardness and pH only had minor effect on the pH of bleach solutions. Increasing hardness to 50 mg/l increased antimicrobial effect of EO water against Escherichia coli O157:H7, but reduced when water hardness further increased to 100 mg/l or higher. Water pH had no effect on EO water produced against E. coli O157:H7. Water hardness had no significant effect on bactericidal activity of EO water against Listeria monocytogenes but elevated water pH decreased bactericidal activity of EO water produced against L. monocytogenes. Bleach solution prepared using hard water at 200 mg/l or at pH 7 or higher had significant lower efficacy in inactivating E. coli O157:H7, but had no effect on the inactivation of L. monocytogenes. Results indicate that increasing the hardness or pH of water used to prepare EO water or bleach solutions will decrease the bactericidal activity of sanitizers prepared from the water.

Food Control 32.2 (2013)

Effects of water hardness and pH on efficacy of chlorine-based sanitizers for inactivating Escherichia coli O157:H7 and Listeria monocytogenes

Food control 33.1 (2013)

Sanitizing effectiveness of commercial “active water” technologies on Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes

Food microbiology 36.1 (2013)

A combined hurdle approach of slightly acidic electrolyzed water simultaneous with ultrasound to inactivate Bacillus cereus on potato

International Journal of Food Microbiology 155.3 (2012)

Roles of hydroxyl radicals in electrolyzed oxidizing water (EOW) for the inactivation of Escherichia coli

The food industry has recognized electrolyzed oxidizing water (EOW) as a promising alternative decontamination technique. However, there is not a consensus about the sanitizing mechanism of EOW. In this study, we evaluated the disinfection efficacy of different types of EOW on Escherichia coli. Based on the hypothesis of hydroxyl radicals existing in EOW, in the present study, the hydroxyl radicals existed in slightly acidic electrolyzed water (SAEW) and acidic electrolyzed water (AEW) diluted to different levels were detected quantitatively. An ultraviolet (UV) spectrophotometer was used to scan EOW with different pH values. Accounting for the results of UV scanning to EOW with different pH value and the disinfection efficacy of different types of EOW, it can be concluded that considering the lower chlorine concentration of EOW compared with traditional chlorine disinfectants, the existing form of chlorine compounds rather than the hydroxyl radicals played important role in the disinfection efficacy of EOW.

Journal of Food Science 77.4 (2012)

Transmission Electron Microscopic Analysis Showing Structural Changes to Bacterial Cells Treated with Electrolyzed Water and an Acidic Sanitizer

The effects of various sanitizers on the viability and cellular injury to structures of Escherichia coli and Listeria innocua were investigated. A food grade organic acidic formulation (pH 2.5) and acidic, neutral, and basic electrolyzed water [AEW (pH 2.7, oxidation reduction potential; ORP: 1100 mV, free available chlorine; FAC: 150 ppm), NEW (pH 6.9, ORP: 840 mV, FAC: 150 ppm), BEW (pH 11.6, ORP: –810 mV)] were used to treat E. coli and L. innocua cells. After 10 min of exposure to the sanitizers, changes to the bacterial numbers and cell structures were evaluated by plate counting and transmission electron microscopy (TEM), respectively. It was concluded from the results that the sanitizers reduced the E. coli cells between 2 and 3 log CFU/mL. Except for the BEW treatment, reductions in L. innocua population were greater (>1 log CFU/mL) than that of E. coli for all treatments. Data from the TEM showed that all sanitizers caused changes to the cell envelope and cytoplasm of both organisms. However, smaller changes were observed for L. innocua cells. Decrease in the integrity of the cell envelope and aggregation of the cytoplasmic components appeared to be mainly because of exposure to the sanitizers. The organic acid formulation and AEW were the most effective sanitizers against bacterial cells, indicating that penetration of acidic substances effectively caused the cell inactivation. Practical Application: An understanding of the method in which E-water and an acidic sanitizer cause injury to E. coli and L. innocua would be helpful in selecting an effective chemical agent as a food safety tool. This will allow a scientist to target similar microorganisms such as food borne bacteria with structures that are vulnerable to the sanitizer.

International Journal of Food Engineering

Slightly acidic electrolyzed water (SAEW) as a novel antimicrobial agent is generated by electrolysis of dilute hydrochloric acid (HCl) and/or sodium chloride (NaCl) solution in a cell with or without a separating membrane. The ultraviolet absorption spectra were used to determine the concentration of hypochlorous acid (HClO) and hypochlorite ion (ClO– ) in SAEW generated by four different methods and their bactericidal efficiency for inactivation of Escherichia coli O157:H7 and Salmonella enteritidis was evaluated. During the production of equivalent available chlorine in SAEW, more HClO was produced by electrolysis of HCl solution in a non-membrane generator and mixing the acid and alkaline electrolyzed water generated in a generator with membrane, compared with the methods of adding HCl to neutral electrolyzed water (NEW) and electrolyzing the mixture of NaCl and HCl solution in a non-membrane cell. At the 10 mg/L available chlorine concentration, SAEW produced by the methods with more HClO generation had significantly higher (p<0.05) bactericidal efficiency for inactivation of both pathogens.

Food Control 22.2 (2011): 318-322

Inhibitory effects of low concentration electrolyzed water and other sanitizers against foodborne pathogens on oyster mushroom

In this study we investigated the effects of low concentration electrolyzed water (LcEW) and several other sanitizers (strong acid electrolyzed water (SAEW), aqueous ozone (AO), 1% citric acid (CA) and sodium hypochlorite solution (NaOCl)) on the inactivation of natural microflora (total aerobic bacteria counts (TBC) and yeasts and moulds (YM)) and foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium and Bacillus cereus) on oyster mushroom. The effects of temperature and treatment time on the antimicrobial activity of LcEW to reduce the populations of foodborne pathogens were also determined. LcEW showed the strongest bactericidal efficacy among all the sanitizers on TBC, YM and pathogens by reductions of 1.35, 1.08 and 1.90–2.16 log CFU/g after 3 min treatment at room temperature (23 ± 2 °C), respectively. There was no significant difference between the antimicrobial effects of LcEW and SAEW (P > 0.05). Among those sanitizers, their relative influence of inactivation was LcEW > NaOCl > CA > AO.

Food Control 22.5 (2011): 792-796

Reduction of Escherichia coli O157:H7 and Salmonella enteritidis on mung bean seeds and sprouts by slightly acidic electrolyzed water

High microbial populations on mung beans and its sprouts are the primary reason of a short shelf life of these products, and potentially present pathogens may cause human illness outbreak. The efficiency for inactivating Escherichia coli O157:H7 (E. coli O157:H7) and Salmonella enteritidis (S. enteritidis), which were artificially inoculated on mung bean seeds and sprouts, by means of slightly acidic electrolyzed water (SAEW, pH 5.0 to 6.5) generated through electrolysis of a mixture of NaCl and hydrochloric acid solution in a non-membrane electrolytic chamber, was evaluated at the different available chlorine concentrations (ACCs, 20–120 mg/l) and treatment time (3–15 min), respectively. The effect of SAEW treatment on the viability of seeds was also determined. Results indicate that the ACC had more significant effect on the bactericidal activity of SAEW for reducing both pathogens on the seeds and sprouts compared to treatment time (P < 0.05). The seeds and sprouts treated with SAEW at ACCs of 20 and 80 mg/l resulted in a reduction of 1.32–1.78 log10 CFU/g and 3.32–4.24 log10 CFU/g for E. coli, while 1.27–1.76 log10 CFU/g and 3.12–4.19 log10 CFU/g for S. enteritidis, respectively. The germination percentage of mung bean seeds was not significantly affected by the treatment of SAEW at an ACC of 20 mg/l for less than 10 min (P > 0.05). The finding of this study implies that SAEW with a near-neutral pH value and low available chlorine is an effective method to reduce foodborne pathogens on seeds and sprouts with less effects on the viability of seeds.

Food control 22.3-4 (2011): 601-607

Application of slightly acidic electrolyzed water as a potential non-thermal food sanitizer for decontamination of fresh ready-to-eat vegetables and sprouts

The sanitization efficacy of slightly acidic electrolyzed water (SAEW) against food pathogens on selected fresh ready-to-eat (RTE) vegetables and sprouts was evaluated and compared to sodium hypochlorite (NaOCl) solution. RTE vegetables and sprouts were dip-inoculated with Escherichia coli (E. coli) and Salmonella spp. and dip-treated with SAEW, NaOCl solution for 5 min. SAEW treatment significantly (p < 0.05) reduced the total aerobic mesophilic bacteria from Chinese celery, lettuce and daikon sprouts by 2.7, 2.5 and 2.45 log10CFU/g, respectively relative to un-treated. Pathogens were significantly (p < 0.05) reduced from Chinese celery, lettuce and daikon sprouts by 2.7, 2.8 and 2.8 log10CFU/g (E. coli) and 2.87, 2.91 and 2.91 log10CFU/g (Salmonella spp.), respectively following a SAEW treatment. SAEW and NaOCl solution showed no significant sanitization difference (p > 0.05). Results demonstrate that SAEW at low chlorine concentration and a near neutral pH is a potential non-thermal food sanitizer that could represent an alternative to NaOCl solution and would reduce the amount of free chlorine used in fresh-cut vegetables industry, since the same microbial reduction as NaOCl solution is obtained.

Journal of food science 75.4 (2010): M231-M238

Efficacy of Sanitized Ice in Reducing Bacterial Load on Fish Fillet and in the Water Collected from the Melted Ice

This study investigated the efficacy of sanitized ice for the reduction of bacteria in the water collected from the ice that melted during storage of whole and filleted Tilapia fish. Also, bacterial reductions on the fish fillets were investigated. The sanitized ice was prepared by freezing solutions of PRO-SAN® (an organic acid formulation) and neutral electrolyzed water (NEW). For the whole fish study, the survival of the natural microflora was determined from the water of the melted ice prepared with PRO-SAN® and tap water. These water samples were collected during an 8 h storage period. For the fish fillet study, samples were inoculated with Escherichia coli K12, Listeria innocua, and Pseudomonas putida then stored on crushed sanitized ice. The efficacies of these were tested by enumerating each bacterial species on the fish fillet and in the water samples at 12 and 24 h intervals for 72 h, respectively. Results showed that each bacterial population was reduced during the test. However, a bacterial reduction of < 1 log CFU was obtained for the fillet samples. A maximum of approximately 2 log CFU and > 3 log CFU reductions were obtained in the waters sampled after the storage of whole fish and the fillets, respectively. These reductions were significantly (P < 0.05) higher in the water from sanitized ice when compared with the water from the unsanitized melted ice. These results showed that the organic acid formulation and NEW considerably reduced the bacterial numbers in the melted ice and thus reduced the potential for cross-contamination.

International Journal of Food Microbiology 139.3 (2010): 147-153

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

The International Journal of Food Microbiology publishes full-length original research papers, short communications, review articles and book reviews covering all aspects of microbiological safety, quality and acceptability of foods. Contributions dealing with the following fields are invited: bacteriology, immunology, mycology, parasitology, virology and food fermentation. Emphasis will be placed on papers dealing with microbiological quality assurance, intrinsic and extrinsic parameters of foods affecting microbial survival and growth, methods for microbiological and immunological examinations of foods, indices of the sanitary quality of foods, incidence and types of food microorganisms, food spoilage, microbiological aspects of food preservation, microbial interaction, predictive microbiology, food-borne diseases of microbial origin and the safety of novel food products. Achievements in rapid methods and automation in food microbiology are also included. It is a policy of this journal also to publish Proceedings of suitable meetings, workshops, conferences, etc. in the field of food microbiology. Related Conference Food Safety Objectives: Public Health, HACCP and Science will take place on December 4-5, 2000 at Georgetown University, Washington DC, USA. The conference will explore ways and means of improving food safety through Food Safety Objectives (FSOs) focussing on the following topics; Testing and Detection; Microbiology; Food Processing Technology; Public Health and Consumer Behavior. For details visit http://www.elsevier.com/locate/fso2000

Food Control 21.10 (2010): 1383-1387

Inactivation effect of newly developed low concentration electrolyzed water and other sanitizers against microorganisms on spinach

The efficacy of newly developed low concentration electrolyzed water (LcEW) was investigated to inactivate the pathogens on spinach leaves as a convenient and safe alternative sanitizer and it was compared to other sanitizers. Spinach leaves were inoculated with Escherichia coli O157:H7 and Listeria monocytogenes and dip treated with deionized water (DIW), LcEW, strong acid electrolyzed water (SAEW), aqueous ozone (AO), 1% citric acid (CA) and sodium hypochlorite solution (NaOCl) for 3 min at room temperature (23 ± 2 °C). For all pathogens, the similar pattern of microbial reduction on spinach was apparent with LcEW and SAEW washing. In the present study, it was found that LcEW inactivated, at maximum, 1.64–2.80 log cfu/g and DIW resulted in lowest reduction, 0.31–0.95 log cfu/g of background or pathogenic microflora present on spinach leaves compared to the unwashed control. The findings of this study indicate that LcEW and SAEW did not differ significantly (P > 0.05) in reducing background or pathogenic microflora on spinach and LcEW may be a promising sanitizer for washing vegetables without environmental pollution instead of using electrolyzed oxidizing (EO) water or SAEW.

Journal of food science 75.5 (2010): M253-M260

Studies on Disinfection Mechanism of Electrolyzed Oxidizing Water on E. coli and Staphylococcus aureus

Abstract: Suspension quantitative germicidal test showed that electrolyzed oxidizing water (EO water) was an efficient and rapid disinfectant. Disinfection rates towards E. coli (available chlorine concentration ACC: 12.40 mg/L) and Staphylococcus aureus (ACC: 37.30 mg/L) could reach 100% at 1 and 3 min, respectively. Disinfection mechanism of EO water was investigated at a molecular biological level by detecting a series of biochemical indices. The results showed that the dehydrogenase activities of E. coli and S. aureus decreased rapidly, respectively, at the rates of 45.9% and 32% in the 1st minute treatment with EO water. EO water also improved the bacterial membrane permeability, causing the rise of conductivities and the rapid leakages of intracellular DNA, K+, and proteins in 1 min. The leakages of DNA and K+ tended to slow down after about 1 min while those of proteins began to decrease a little after reaching the peak values. The sodium dodecyl sulfonate polyacrylamide gel electrophoresis (SDS-PAGE) showed that EO water destroyed intracellular proteins. The protein bands got fainter and even disappeared as the treatment proceeded. EO water's effects on the bacterial ultrastructures were also verified by the transmission electronic microscopy (TEM) photos. The disinfection mechanism of EO water was composed of several comprehensive factors including the destruction of bacterial protective barriers, the increase of membrane permeability, the leakage of cellular inclusions, and the activity decrease of some key enzymes.

Journal of Bioscience and Bioengineering 110.3 (2010): 308-313

In vitro inactivation of Escherichia coli, Staphylococcus aureus and Salmonella spp. using slightly acidic electrolyzed water

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, 23mg/l available chlorine concentration; ACC; and 940mV 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 9ml of SAEW, strong acidic electrolyzed water (StAEW; ca. 50mg/l ACC), sodium hypochlorite solution (NaOCl; ca.120mg/l ACC) and distilled water (DW) as control and treated for 60s. 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>0.05). However, the bactericidal effect of StAEW was significantly higher (p<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>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.

African Journal of Microbiology Research 4.20 (2010): 2174-2180

Antimicrobial effect of slightly acidic electrolyzed water for inactivation of Salmonella spp. and Escherichia colion fresh strawberries (Fragaria L.)

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.

Journal of Food Science 75.2 (2010): M111-M115

Combined Effects of Alkaline Electrolyzed Water and Citric Acid with Mild Heat to Control Microorganisms on Cabbage

Effects of alkaline electrolyzed water (AlEW), acidic electrolyzed water (AcEW), 100 ppm sodium hypochlorite (NaClO), deionized water (DIW), 1% citric acid (CA) alone, and combinations of AlEW with 1% CA (AlEW + CA), in reducing the populations of spoilage bacteria and foodborne pathogens on cabbage were investigated at various dipping times (3, 5, and 10 min) with different dipping temperatures (1, 20, 40, and 50 degrees C). Inhibitory effect of the selected optimal treatment against Listeria monocytogenes and Escherichia coli O157 : H7 on cabbage were also evaluated. Compared to the untreated control, AlEW treatment most effectively reduced the numbers of total bacteria, yeast, and mold, followed by AcEW and 100-ppm NaClO treatments. All treatments dip washed for 5 min significantly reduced the numbers of total bacteria, yeast, and mold on cabbage. With increasing dipping temperature from 1 to 50 degrees C, the reductions of total bacteria, yeast, and mold were significantly increased from 0.19 to 1.12 log CFU/g in the DIW wash treatment (P < 0.05). Combined 1% CA with AlEW treatment at 50 degrees C showed the reduction of around 3.98 and 3.45 log CFU/g on the total count, and yeast and mold, effective reduction of L. monocytogenes (3.99 log CFU/g), and E. coli O157 : H7 (4.19 log CFU/g) on cabbage. The results suggest that combining AlEW with CA could be a possible method to control foodborne pathogens and spoilage bacteria effectively on produce

Journal of Food Quality 33.5 (2010): 559-577

EFFICACY OF ELECTROLYZED OXIDIZING (EO) WATER AND CHLORINATED WATER FOR INACTIVATION OF ESCHERICHIA COLI O157:H7 ON STRAWBERRIES AND BROCCOLI

Inoculated strawberries were treated with deionized water (control), electrolyzed oxidizing (EO) water (23 and 55 mg/L of residual chlorine), andchlorinated water (55 mg/L of residual chlorine), either with or without ultra-sonication. Inoculated broccoli was treated with EO water containing 55 and 100 mg/L of residual chlorine and chlorinated water with 100 mg/L of residual chlorine. Treatments were conducted for 1 and 5 min at temperatures of 4 and 24C, respectively. Dipping strawberries and broccoli into EO water or chlo-rinated water signiﬁcantly (P < 0.05) reduced the Escherichia coli O157:H7 counts compared with inoculated controls. Dipping inoculated strawberries with chlorinated water or EO water with ultrasonication reduced E. coli O157:H7 cells by 0.7 to 1.9 log cfu/g depending on the treatment time and treatment solution temperature. Dipping inoculated broccoli into chlorinated water or EO water with ultrasonication for 1 or 5 min reduced the bacterial population by 1.2 to 2.2 log cfu/g. Signiﬁcant (P < 0.05) reductions in patho-gen populations were observed when produce was treated with EO water in conjunction with ultrasonication. Results revealed that EO water was either more than or as effective as chlorinated water in killing E. coli O157:H7 cells on strawberries and broccoli.

Journal of Food Protection 73.12 (2010): 2211-2216

Effect of slightly acidic electrolyzed water for inactivating Escherichia coli O157:H7 and Staphylococcus aureus analyzed by transmission electron microscopy

The use of different available chlorine concentrations (ACCs) of slightly acidic electrolyzed water (SAEW; 0.5 to 30 mg/liter), different treatment times, and different temperatures for inactivating Escherichia coli O157:H7 and Staphylococcus aureus was evaluated. The morphology of both pathogens also was analyzed with transmission electron microscopy. A 3-min treatment with SAEW (pH 6.0 to 6.5) at ACCs of 2 mg/liter for E. coli O157:H7 and 8 mg/liter for S. aureus resulted in 100% inactivation of two cultures (7.92- to 8.75-log reduction) at 25°C. The bactericidal activity of SAEW was independent of the treatment time and temperature at a higher ACC (P > 0.05). E. coli O157:H7 was much more sensitive than S. aureus to SAEW. The morphological damage to E. coli O157:H7 cells by SAEW was significantly greater than that to S. aureus cells. At an ACC as high as 30 mg/liter, E. coli O157:H7 cells were damaged, but S. aureus cells retained their structure and no cell wall damage or shrinkage was observed. SAEW with a near neutral pH may be a promising disinfectant for inactivation of foodborne pathogens.

International Journal of Food Microbiology 132.2 (2009): 134-140

Efficacy of chlorine, acidic electrolyzed water and aqueous chlorine dioxide solutions to decontaminate Escherichia coli O157:H7 from lettuce leaves

This study compared the efficacy of chlorine (20-200 ppm), acidic electrolyzed water (50 ppm chlorine, pH 2.6), acidified sodium chlorite (20-200 ppm chlorite ion concentration, Sanova), and aqueous chlorine dioxide (20-200 ppm chlorite ion concentration, TriNova) washes in reducing populations of Escherichia coli O157:H7 on artificially inoculated lettuce. Fresh-cut leaves of Romaine or Iceberg lettuce were inoculated by immersion in water containing E. coli O157:H7 (8 log CFU/ml) for 5 min and dried in a salad spinner. Leaves (25 g) were then washed for 2 min, immediately or following 24 h of storage at 4 degrees C. The washing treatments containing chlorite ion concentrations of 100 and 200 ppm were the most effective against E. coli O157:H7 populations on Iceberg lettuce, with log reductions as high as 1.25 log CFU/g and 1.05 log CFU/g for TriNova and Sanova wash treatments, respectively. All other wash treatments resulted in population reductions of less than 1 log CFU/g. Chlorine (200 ppm), TriNova, Sanova, and acidic electrolyzed water were all equally effective against E. coli O157:H7 on Romaine, with log reductions of approximately 1 log CFU/g. The 20 ppm chlorine wash was as effective as the deionized water wash in reducing populations of E. coli O157:H7 on Romaine and Iceberg lettuce. Scanning electron microscopy indicated that E. coli O157:H7 that was incorporated into biofilms or located in damage lettuce tissue remained on the lettuce leaf, while individual cells on undamaged leaf surfaces were more likely to be washed away.

Food Microbiology 26.4 (2009): 386-390

The decontaminative effects of acidic electrolyzed water for Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes on green onions and tomatoes with differing organic demands

Acidic electrolyzed water (AC-EW) has strong bactericidal activity against foodborne pathogens on fresh vegetables. However, the efficacy of AC-EW is influenced by soil or other organic materials present. This study examined the bactericidal activity of AC-EW in the presence of organic matter, in the form of bovine serum against foodborne pathogens on the surfaces of green onions and tomatoes. Green onions and tomatoes were inoculated with a culture cocktail of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes. Treatment of these organisms with AC-EW containing bovine serum concentrations of 5, 10, 15, and 20 ml/l was performed for 15 s, 30 s, 1 min, 3 min and 5 min. The total residual chlorine concentrations of AC-EW decreased proportional to the addition of serum. The bactericidal activity of AC-EW also decreased with increasing bovine serum concentration, whereas unamended AC-EW treatment reduced levels of cells to below the detection limit (0.7 logCFU/g) within 3 min.

Journal of Food Engineering 91.4 (2009): 582-586

Physicochemical properties and bactericidal efficiency of neutral and acidic electrolyzed water under different storage conditions

Neutral (NEW) and acidic (AEW) electrolyzed water were stored in open or closed glass bottles under light or dark conditions at 20 °C for 30 days. The pH, oxidation–reduction potential (ORP), electrical conductivity (EC), available chlorine concentration (ACC), dissolved oxygen (DO), and bactericidal efficiency of NEW and AEW were determined during storage or before and after storage, respectively. The pH and EC of NEW and AEW remained unchanged in storage. The ORP, ACC and DO of AEW decreased 22%, 100% and 52% under open storage conditions, respectively. Light had no significant effects on the physicochemical properties of NEW (P > 0.05). Bactericidal efficiency was not markedly affected by storage conditions for NEW, but decreased significantly for AEW under open storage conditions. Electrolyzed water should be stored in closed containers or used immediately to prevent the loss of available chlorine that is one of the main contributing factors for antimicrobial activity.

Food Microbiology 25.1 (2008): 36-41

Reduction of bacteria on spinach, lettuce, and surfaces in food service areas using neutral electrolyzed oxidizing water

Food safety issues and increases in food borne illnesses have promulgated the development of new sanitation methods to eliminate pathogenic organisms on foods and surfaces in food service areas. Electrolyzed oxidizing water (EO water) shows promise as an environmentally friendly broad spectrum microbial decontamination agent. EO water is generated by the passage of a dilute salt solution (∼1% NaCl) through an electrochemical cell. This electrolytic process converts chloride ions and water molecules into chlorine oxidants (Cl2, HOCl/ClO−). At a near-neutral pH (pH 6.3–6.5), the predominant chemical species is the highly biocidal hypochlorous acid species (HOCl) with the oxidation reduction potential (ORP) of the solution ranging from 800 to 900 mV. The biocidal activity of near-neutral EO water was evaluated at 25 °C using pure cultures of Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis. Treatment of these organisms, in pure culture, with EO water at concentrations of 20, 50, 100, and 120 ppm total residual chlorine (TRC) and 10 min of contact time resulted in 100% inactivation of all five organisms (reduction of 6.1–6.7 log10 CFU/mL). Spray treatment of surfaces in food service areas with EO water containing 278–310 ppm TRC (pH 6.38) resulted in a 79–100% reduction of microbial growth. Dip (10 min) treatment of spinach at 100 and 120 ppm TRC resulted in a 4.0–5.0 log10 CFU/mL reduction of bacterial counts for all organisms tested. Dipping (10 min) of lettuce at 100 and 120 ppm TRC reduced bacterial counts of E. coli by 0.24–0.25 log10 CFU/mL and reduced all other organisms by 2.43–3.81 log10 CFU/mL.

Journal of Food Science 73.6 (2008): M268-M272

Effect of Electrolyzed Water for Reduction of Foodborne Pathogens on Lettuce and Spinach

The ability of electrolyzed water (EW) to inactivate foodborne pathogens on the surfaces of lettuce and spinach was investigated. Lettuce and spinach leaves were inoculated with a cocktail of 3 strains each of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes and treated with acidic electrolyzed water (AC-EW), alkaline electrolyzed water (AK-EW), alkaline electrolyzed water followed by acidic electrolyzed water (sequential treatment, AK-EW + AC-EW), deionized water followed by acidic electrolyzed water (sequential treatment, DW + AC-EW), and deionized water (control, DW) for 15, 30 s, and 1, 3, and 5 min at room temperature (22 ± 2 °C). For all 3 pathogens, the same pattern of microbial reduction on lettuce and spinach were apparent. The relative efficacy of reduction was AC-EW > DW + AC-EW ≈ AK-EW + AC-EW > AK-EW > control. After a 3-min treatment of AC-EW, the 3 tested pathogens were reduced below the detection limit (0.7 log). DW + AC-EW and AK-EW + AC-EW produced the same levels of reduction after 5 min when compared to the control. AK-EW did not reduce levels of pathogens even after a 5-min treatment on lettuce and spinach. Results suggest that AC-EW treatment was able to significantly reduce populations of the 3 tested pathogens from the surfaces of lettuce and spinach with increasing time of exposure.

International Journal of Food Microbiology 123.1 (2008): 151-158

Efficacy of neutral electrolyzed water (NEW) for reducing microbial contamination on minimally-processed vegetables

Consumption of minimally-processed, or fresh-cut, fruit and vegetables has rapidly increased in recent years, but there have also been several reported outbreaks associated with the consumption of these products. Sodium hypochlorite is currently the most widespread disinfectant used by fresh-cut industries. Neutral electrolyzed water (NEW) is a novel disinfection system that could represent an alternative to sodium hypochlorite. The aim of the study was to determine whether NEW could replace sodium hypochlorite in the fresh-cut produce industry. The effects of NEW, applied in different concentrations, at different treatment temperatures and for different times, in the reduction of the foodborne pathogens Salmonella, Listeria monocytogenes and Escherichia coli O157:H7 and against the spoilage bacterium Erwinia carotovora were tested in lettuce. Lettuce was artificially inoculated by dipping it in a suspension of the studied pathogens at 10(8), 10(7) or 10(5) cfu ml(-1), depending on the assay. The NEW treatment was always compared with washing with deionized water and with a standard hypochlorite treatment. The effect of inoculum size was also studied. Finally, the effect of NEW on the indigenous microbiota of different packaged fresh-cut products was also determined. The bactericidal activity of diluted NEW (containing approximately 50 ppm of free chlorine, pH 8.60) against E. coli O157:H7, Salmonella, L. innocua and E. carotovora on lettuce was similar to that of chlorinated water (120 ppm of free chlorine) with reductions of 1-2 log units. There were generally no significant differences when treating lettuce with NEW for 1 and 3 min. Neither inoculation dose (10(7) or 10(5) cfu ml(-1)) influenced the bacterial reduction achieved. Treating fresh-cut lettuce, carrot, endive, corn salad and 'Four seasons' salad with NEW 1:5 (containing about 50 ppm of free chlorine) was equally effective as applying chlorinated water at 120 ppm. Microbial reduction depended on the vegetable tested: NEW and sodium hypochlorite treatments were more effective on carrot and endive than on iceberg lettuce, 'Four seasons' salad and corn salad. The reductions of indigenous microbiota were smaller than those obtained with the artificially inoculated bacteria tested (0.5-1.2 log reduction). NEW seems to be a promising disinfection method as it would allow to reduce the amount of free chlorine used for the disinfection of fresh-cut produce by the food industry, as the same microbial reduction as sodium hypochlorite is obtained. This would constitute a safer, 'in situ', and easier to handle way of ensuring food safety.

Poultry science 86.10 (2007): 2239-2244

Poultry Science An official journal of the Poultry Science Association.

Journal of Food Science 72.9 (2007): M397-M406

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

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×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 °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 log10 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 log10 CFU/mL of rinse fluid reduction of L. monocytogenes and E. coli O157:H7, respectively, ≥ 2.60 log10 CFU/mL of rinse fluid reduction of L. monocytogenes and up to 2.35 and 3.12 log10 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.

Food Control 18.11 (2007): 1383-1390

Efficacy of sanitizers in reducing Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes populations on fresh-cut carrots

Shredded carrots were inoculated with Escherichia coli O157:H7, Salmonella or Listeria monocytogenes and washed for 1 or 2 min with chlorine (Cl; 200 ppm), peroxyacetic acid (PA; 40 ppm) or acidified sodium chlorite (ASC; 100, 200, 500 ppm) under simulated commercial processing conditions. After washed, the carrots were spin dried, packaged and stored at 5 °C for up to 10 days. Bacterial enumeration was significantly (P ⩽ 0.05) reduced by 1, 1.5 and 2.5 log CFU/g after washing with ASC 100, 250 and 500 ppm, respectively. All sanitizers reduced pathogen load below that of tap water wash and unwashed controls. During storage at 5 °C the bacterial load of all treatments increased gradually, but to different extent in different treatments. ASC inhibited bacterial growth more effectively than the other sanitizers and also maintained the lowest pathogen counts (<1 log CFU/g) during storage. Organic matter in the process water significantly (P ⩽ 0.05) reduced the antibacterial efficacy of Cl, but not that of PA or ASC. Therefore, ASC shows the potential to be used as a commercial sanitizer for washing shredded carrots.

Journal of Food Protection 69.7 (2006): 1616-1622

Electrolyzed Oxidizing Anode Water as a Sanitizer for Use in Abattoirs

The effectiveness of electrolyzed oxidizing anode (EOA) water (oxidation-reduction potential, 1,120 mV; pH 2.0) as asanitizer for use in abattoirs was compared with the iodophor (IOD) Mikroklene (25 ppm), a sanitizer approved for use byregulatory authorities in Canada and the United States. A total of 240 swab (100 cm2) samples were obtained from 4 sites onthe kill floor and 16 sites in the secondary processing areas, during two visits within a 4-week period to each of three meatpacking plants, processing50 animals per week. Swabs were obtained 12 h after the application of IOD and EOA and wereanalyzed for the presence of total aerobic bacteria, total coliforms, and totalEscherichia coli.Total aerobic bacteria (log CFU/100 cm2) recovered from the 20 sample sites were lower (P0.0001) in EOA as compared with IOD (2.940.12 versus3.750.12, respectively). Plant A was 1.5 times more likely (P0.0001) to have a sampling site positive for the presenceof coliforms andE. colithan plants B and C. There was no difference (P0.05) between treatment IOD or EOA in thelikelihood of obtaining a positive sample for the presence of total coliforms orE. coliamong the three plants. When the killfloor and secondary processing areas are compared, the likelihood of obtaining a sample positive for coliforms orE. coliwassimilar (P0.05). Results indicate that EOA was more effective than IOD in reducing populations of total aerobic bacteriaon equipment surfaces in the three meat packing plants studied. Because the likelihood of obtaining a positive sample forcoliforms orE. coliin EOA as compared with IOD was similar, EOA may be a suitable alternative or complement to IODas a sanitizer in small- to medium-sized abattoirs. Additional research is required to further evaluate the effectiveness of EOAto sanitize processing equipment on the basis of subsequent isolation of aerobes, coliforms, andE. colifrom meat products.

Letters in Applied Microbiology 40.5 (2005): 341-346

Inactivation of Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa and Staphylococcus aureus on stainless steel and glass surfaces by neutral electrolysed water

Aim: To ascertain the efficacy of neutral electrolysed water (NEW) in reducing Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes on glass and stainless steel surfaces. Its effectiveness for that purpose is compared with that of a sodium hypochlorite (NaClO) solution with similar pH, oxidation–reduction potential (ORP) and active chlorine content. Methods and Results: First, the bactericidal activity of NEW was evaluated over pure cultures (8·5 log CFU ml−1) of the abovementioned strains: all of them were reduced by more than 7 log CFU ml−1 within 5 min of exposure either to NEW (63 mg l−1 active chlorine) or to NaClO solution (62 mg l−1 active chlorine). Then, stainless steel and glass surfaces were inoculated with the same strains and rinsed for 1 min in either NEW, NaClO solution or deionized water (control). In the first two cases, the populations of all the strains decreased by more than 6 log CFU 50 cm−2. No significant difference (P ≤ 0·05) was found between the final populations of each strain with regard to the treatment solutions (NEW or NaClO solution) or to the type of surface. Conclusions: NEW was revealed to be as effective as NaClO at significantly reducing the presence of pathogenic and spoilage bacteria (in this study, E. coli, L. monocytogenes, P. aeruginosa and S. aureus) on stainless steel and glass surfaces. Significance and Impact of the Study: NEW has the advantage of being safer than NaClO and easier to handle. Hence, it represents an advantageous alternative for the disinfection of surfaces in the food industry.

Meat Science 71.1 (2005): 79-91

Post-harvest interventions to reduce/eliminate pathogens in beef M. Koohmaraie * , T.M. Arthur, J.M. Bosilevac, M. Guerini, S.D. Shackelford, T.L. Wheeler

In 1999 the foodborne pathogensSalmonella,Listeria,Campylobacter, andEscherichia coli(both O157 and non-O157) were esti-mated to cause more than 6 million illnesses and approximately 9000 deaths each year. However, the most recent Centers for DiseaseControl and Prevention report on the sources and incidence of foodborne disease, released in 2004, has shown a dramatic decrease inE. coliO157:H7 infections. Since raw beef products are the most frequently foodborne sources of these pathogens, the results of thisreport demonstrate that the microbiological quality of raw beef has improved greatly. During the intervening years, post-harvestinterventions have continually improved, with new attention to hide decontamination and innovative treatments of carcasses. Inaddition, a system to hold and test beef trim or ground beef forE. coliO157:H7 before its release into commerce has providedan even greater level of safety. In this paper, we review the latest information on the prevalence ofE. coliO157:H7 and other patho-gens on beef, the evidence identifying the hide as the primary source of pathogens on beef carcasses, the efficacy of various hide andcarcass interventions, and other developments that have led or have the potential to lead to even greater improvements in the micro-bial quality of beef.Published by Elsevier Ltd.

International Journal of Food Microbiology 91.1 (2004): 13-18

Effects of chlorine and pH on efficacy of electrolyzed water for inactivating Escherichia coli O157:H7 and Listeria monocytogenes

The effects of chlorine and pH on the bactericidal activity of electrolyzed (EO) water were examined against Escherichia coli O157:H7 and Listeria monocytogenes. The residual chlorine concentration of EO water ranged from 0.1 to 5.0 mg/l, and the pH effect was examined at pH 3.0, 5.0, and 7.0. The bactericidal activity of EO water increased with residual chlorine concentration for both pathogens, and complete inactivation was achieved at residual chlorine levels equal to or higher than 1.0 mg/l. The results showed that both pathogens are very sensitive to chlorine, and residual chlorine level of EO water should be maintained at 1.0 mg/l or higher for practical applications. For each residual chlorine level, bactericidal activity of EO water increased with decreasing pH for both pathogens. However, with sufficient residual chlorine (greater than 2 mg/l), EO water can be applied in a pH range between 2.6 (original pH of EO water) and 7.0 while still achieving complete inactivation of E. coli O157:H7 and L. monocytogenes.

Poultry Science 83.12 (2004): 2071-2078

Poultry Science An official journal of the Poultry Science Association.

2004 ASAE Annual Meeting. American Society of Agricultural and Biological Engineers, 2004

Use of electrolyzed oxidizing water to inactivate Escherichia coli O157:H7 and Listeria monocytogenes Scott A on raw salmon

Raw fish is prone to risk of microbial outbreaks due to contamination of pathogenic microorganisms. Escherichia coli O157:H7 and Listeria monocytogenes are among the pathogens associated with raw fish. Therefore, it is important to treat raw fish to inactivate pathogenic microorganisms. Electrolyzed oxidizing water is novel antimicrobial agent containing acidic solution with a pH of 2.6- 2.9, ORP of 1120 1180 mV, and 76-90 ppm free chlorine, and alkaline solution with a pH of 11.5 and ORP of 795 mV. This study was undertaken to evaluate the efficacy of electrolyzed oxidizing (EO) water for inactivation of E. coli O157:H7 and L. monocytogenes Scott A on the surfaces (muscle and skin surfaces) of inoculated salmon fillets. Inoculated salmon fillets were treated only with acidic EO water at 22C and 35C and sodium hypochlorite solution (90 ppm free chlorine) as control at 22C for 2, 4, 8, 16, 32, and 64 min, respectively. For the treatment with alkaline EO water followed by acidic EO water, a response surface model was developed to predict effective times in the range of 5-30 min and temperatures in the range of 22-35C for both alkaline and acidic water treatments. The acidic EO water treatments resulted in reductions of population of L. monocytogenes Scott A ranging from 0.40 log10 CFU/g (60 %) at 22oC to 1.12 log10 CFU/g (92.3 %) at 35oC. Treatment of inoculated salmon fillets in acidic EO water reduced E. coli O157:H7 populations by 0.49 log10 CFU/g (67 %) 22C and 1.07 log10 CFU/g (91.1 %) at 35C, respectively. Response surface analysis for alkaline EO water treatment followed by acidic treatment demonstrated that, maximum log reduction of 1.33 log10 CFU/g (95.3 %) for E. coli O157:H7 and 1.09 log10 CFU/g (91.9 %) for L. monocytogenes Scott A.

Journal of Food Science 68.3 (2003): 1013-1017

The Effect of pH on Inactivation of Pathogenic Bacteria on Fresh-cut Lettuce by Dipping Treatment with Electrolyzed Water

Fresh-cut lettuce samples inoculated with S. Typhimurium, E. coli O157:H7 or L. monocytogeneswere dipped into 300 ppm electrolyzed water (EW ) at pH 4 to 9 and 30 °C for 5 min. The effects of treatment pHon bacterial reduction and visual quality of the lettuce were determined. The treatments at pH 4 and 8 resulted inthe most effective inactivation of E. coli O157:H7, but the effect of pH was not significant (P > 0.05) for S.Typhimurium and L. monocytogenes. The treatment at pH 7 retained the best visual quality of lettuce, andachieved a reduction of approximately 2 log CFU/g for above 3 bacteria.Keywords: fresh-cut vegetables, electrolyzed water, dipping treatment, pH, bacterial reduction

International Journal of Food Microbiology 86.3 (2003): 231-237

Treatment of Escherichia coli O157:H7 inoculated alfalfa seeds and sprouts with electrolyzed oxidizing water

Electrolyzed oxidizing water is a relatively new concept that has been utilized in agriculture, livestock management, medical sterilization, and food sanitation. Electrolyzed oxidizing (EO) water generated by passing sodium chloride solution through an EO water generator was used to treat alfalfa seeds and sprouts inoculated with a five-strain cocktail of nalidixic acid resistant Escherichia coli O157:H7. EO water had a pH of 2.6, an oxidation–reduction potential of 1150 mV and about 50 ppm free chlorine. The percentage reduction in bacterial load was determined for reaction times of 2, 4, 8, 16, 32, and 64 min. Mechanical agitation was done while treating the seeds at different time intervals to increase the effectiveness of the treatment. Since E. coli O157:H7 was released due to soaking during treatment, the initial counts on seeds and sprouts were determined by soaking the contaminated seeds/sprouts in 0.1% peptone water for a period equivalent to treatment time. The samples were then pummeled in 0.1% peptone water and spread plated on tryptic soy agar with 50 μg/ml of nalidixic acid (TSAN). Results showed that there were reductions between 38.2% and 97.1% (0.22–1.56 log10 CFU/g) in the bacterial load of treated seeds. The reductions for sprouts were between 91.1% and 99.8% (1.05–2.72 log10 CFU/g). An increase in treatment time increased the percentage reduction of E. coli O157:H7. However, germination of the treated seeds reduced from 92% to 49% as amperage to make EO water and soaking time increased. EO water did not cause any visible damage to the sprouts.

Journal of Food Science 66.9: 1368-1372

Pathogen Reduction and Quality of Lettuce Treated with Electrolyzed Oxidizing and Acidified Chlorinated Water

The efficacy of electrolyzed oxidizing (EO) and acidified chlorinated water (45 ppm residual chlorine) was evaluated in killing Escherichia coli O157:H7 and Listeria monocytogenes on lettuce. After surface inoculation, each leaf was immersed in 1.5 L of EO or acidified chlorinated water for 1 or 3 min at 22 °C. Compared to a water wash only, the EO water washes significantly decreased mean populations of E. coli O157:H7 and L. monocytogenes by 2.41 and 2.65 log10 CFU per lettuce leaf for 3 min treatments, respectively (p < 0.05). However, the difference between the bactericidal activity of EO and acidified chlorinated waters was not significant (p > 0.05). Change in the quality of lettuce subjected to the different wash treatments was not significant at the end of 2 wk of storage.

Journal Japanese Society of Food Science and Technology 48.11 (2001): 827-834

Sterilization Effect and Influence on Food Surface by Acidic Electrolyzed Water Treatment

Recently, several reports about sterilization effect of electrolyzed water have been published. The electrolyzed water is expected as one of attractive application for sanitation of fresh food, however, to install this electrolyzed water, we have to clear the potential of the microorganism control for real food. In this paper, we try to reveal the mechanism of the microorganism control, and also try to check the food quality change during the treatment. Therefore, to evaluate the effect of the electrolyzed water, we examined the several test for making sterilization mechanism clear and observed microorganism behavior on food surface. At first, for the purpose of making sterilization effects clear in vitro condition, we did microorganism test with several injection ratio and number. Then, we studied the effects of catalase on the enumeration of stressed Escherichia coli cells after acidic electrolyzed water treatment. Moreover, we studied sterilization effect of acidic electrolyzed water for E. coli on an agar block on the assumption as one of food model. In addition, we studied sterilization effects for sliced raw tuna as one sample of food surface treatment. The change in the quality of food surface was observed by scanning electron microscope, color meter and so on. Steriliaation effects are dependent the condition of injection ratio and mixing numbers. These results suggest that it is important to keep available chlorine concentration for keeping the potential to the microorganisms'control. The increasing of E. coli number with the addition of catalase was suggested that the weak concentration of electrolyzed water gave the injured microbes. The Observation of cultivated E. coli behavior on agar block showed the microorganism behavior. Acidic electrolyzed water sterilizes microorganisms on sliced raw tuna, however, after treatment, the color change of surface of tuna and the protein denaturation were observed. These results suggest that when the electrolyzed water treatment is applied to control the microorganism on surface, the effect against food surface must be considered.

Analytical Sciences 16.4 (2000): 365-369

The Efficiency of Disinfection of Acidic Electrolyzed Water in the Presence of Organic Materials

Acidic electrolyzed water (acidic EW), which is prepared by the electrolysis of an aqueous NaCl solution, has recentlybecome of great importance for disinfection in a variety of fields, including medicine, the food industry and agriculture.In a previous paper we showed that: 1) acidic EW is a mixture of hypocholorite ion, hypochlorous acid and chlorine,depending upon the pH; 2) hypochlorous acid is primarily responsible for disinfection in the case of Escherichia coliK12and Bacillus subtilisPCI219, both in clean culture media. In practice, however, the use of acidic EW is in many casesseverely hampered due to the presence of a variety of non-selective reducing agents. In view of the salient nature ofacidic EW, it is therefore strongly urged to establish an optimum way to use acidic EW in a variety of systems. Thepresent paper is the first report on our attempt along this line in order to characterize the nature of the chemical changesthat the bactericidal activity of the acidic EW deteriorates in the presence of organic materials, which include amino acids and proteins.

International Journal of Food Microbiology 61.2 (2000): 199-207

Efficacy of electrolyzed oxidizing (EO) and chemically modified water on different types of foodborne pathogens

This study was undertaken to evaluate the efficacy of electrolyzed oxidizing (EO) and chemically modified water with properties similar to the EO water for inactivation of different types of foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes and Bacillus cereus). A five-strain cocktail of each microorganism was exposed to deionized water (control), EO water and chemically modified water. To evaluate the effect of individual properties (pH, oxidation–reduction potential (ORP) and residual chlorine) of treatment solutions on microbial inactivation, iron was added to reduce ORP readings and neutralizing buffer was added to neutralize chlorine. Inactivation of E. coli O157:H7 occurred within 30 s after application of JAW EO water with 10 mg/l residual chlorine and chemically modified solutions containing 13 mg/l residual chlorine. Inactivation of Gram-positive and -negative microorganisms occurred within 10 s after application of ROX EO water with 56 mg/l residual chlorine and chemically modified solutions containing 60 mg/l residual chlorine. B. cereus was more resistant to the treatments than E. coli O157:H7 and L. monocytogenes and only 3 log10 reductions were achieved after 10 s of ROX EO water treatment. B. cereus spores were the most resistant pathogen. However, more than 3 log10 reductions were achieved with 120-s EO water treatment.

Applied and Environmental Microbiology 65.9 (1999): 4276-4279

Efficacy of Electrolyzed Oxidizing Water for Inactivating Escherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes

The efficacy of electrolyzed oxidizing water for inactivatingEscherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes was evaluated. A five-strain mixture of E. coli O157:H7,S. enteritidis, or L. monocytogenes of approximately 108 CFU/ml was inoculated in 9 ml of electrolyzed oxidizing water (treatment) or 9 ml of sterile, deionized water (control) and incubated at 4 or 23°C for 0, 5, 10, and 15 min; at 35°C for 0, 2, 4, and 6 min; or at 45°C for 0, 1, 3, and 5 min. The surviving population of each pathogen at each sampling time was determined on tryptic soy agar. At 4 or 23°C, an exposure time of 5 min reduced the populations of all three pathogens in the treatment samples by approximately 7 log CFU/ml, with complete inactivation by 10 min of exposure. A reduction of ≥7 log CFU/ml in the levels of the three pathogens occurred in the treatment samples incubated for 1 min at 45°C or for 2 min at 35°C. The bacterial counts of all three pathogens in control samples remained the same throughout the incubation at all four temperatures. Results indicate that electrolyzed oxidizing water may be a useful disinfectant, but appropriate applications need to be validated. Enterohemorrhagic Escherichia coli O157:H7, Salmonella enteritidis, andListeria monocytogenes are food-borne pathogens of major public health concern in the United States. A variety of foods, including poultry, eggs, meat, milk, fruits, and vegetables, have been implicated as vehicles of one or more of these pathogens in outbreaks of food-borne illness (2, 4, 5). The Pathogen Reduction program of the U.S. Department of Agriculture Food Safety and Inspection Service recommends antimicrobial treatments as a method for reducing or inactivating pathogenic bacteria in foods (13). Effective methods of reducing or eliminating pathogens in foods are important to the successful implementation of Hazard Analysis and Critical Control Point (HACCP) programs by the food industry and for the establishment of critical control points in restaurants, homes, and other food service units. Washing of raw agricultural produce with water is practiced in the industry; however, washing alone does not render the product completely free from pathogens. Although many chemicals generally recognized as safe (GRAS), including organic acids, possess antimicrobial activity against food-borne pathogens, none can eliminate high populations of pathogens when they are used individually at concentrations acceptable in foods. Treatments of fruits and vegetables with water containing sanitizers, including chlorine, may reduce but not eliminate pathogens on the surface of produce (2, 14). Hence, there is a need for, and interest in, developing practical and effective antimicrobial treatments for the inactivation of pathogenic microorganisms on foods.

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