Electrolyzed Oxidizing Water Treatment Research Articles

Electrolyzed Oxidizing Water Modulates the Immune Response in BALB/c Mice Experimentally Infected with Trypanosoma cruzi

Chagas disease is a major public health problem in Latin America. The mixed Th1/Th2 immune response is required against Trypanosoma cruzi. Electrolyzed oxidizing water (EOW) has been shown to have germicidal efficacy. The objective of this study was to evaluate the EOW effectiveness in T. cruzi-infected BALB/c mice clinically, immunologically, and histologically. The severity of the infection was assessed by parasitaemia, general health condition, mortality, mega syndromes, and histological lesions. IgG, TNF-alpha, IFN-gamma, and IL-1 beta levels were quantified. The EOW administration showed a beneficial effect on parasitaemia, general physical condition, and mortality. High levels of IgG1 at 50 days postinfection were observed. Prophylactic EOW treatment was able to induce a predominantly TH1 immune response based on an IgG2a levels increase at the late acute phase, and a 10-fold increase of IFN-gamma in whole acute phase. EOW was able to control the acute phase infection as effectively as benznidazole. Splenomegaly was caused by EOW treatment and lymphadenopathy was stimulated by T. cruzi infection in all groups. Severe tissue damage was not prevented by EOW treatments. Moderate efficacy may be due to immunomodulatory properties and not to a direct toxic effect on the parasite.

Comparative antibacterial activities of neutral electrolyzed oxidizing water and other chlorine-based sanitizers

There is increasing demand for safe and effective sanitizers for irrigation water disinfection to prevent transmission of foodborne pathogens to fresh produce. Here we compared the efficacy of pH-neutral electrolyzed oxidizing water (EOW), sodium hypochlorite (NaClO) and chlorine dioxide (ClO2) against single and mixed populations of E. coli, Listeria and Salmonella under a range of pH and organic matter content. EOW treatment of the mixed bacterial suspension resulted in a dose-dependent (<1 mg/L free chlorine), rapid (<2 min) and effective (4–6 Log10) reduction of the microbial load in water devoid of organic matter under the range of pH conditions tested (pH, 6.0, 7.0, 8.4 and 9.2). The efficacy of EOW containing 5 mg/L free chlorine was unaffected by increasing organic matter, and compared favourably with equivalent concentrations of NaClO and ClO2. EOW at 20 mg/L free chlorine was more effective than NaClO and ClO2 in reducing bacterial populations in the presence of high (20–100 mg/L) dissolved organic carbon, and no regrowth or metabolic activity was observed for EOW-treated bacteria at this concentration upon reculturing in rich media. Thus, EOW is as effective or more effective than other common chlorine-based sanitizers for pathogen reduction in contaminated water. EOW’s other characteristics, such as neutral pH and ease of handling, indicate its suitability for fresh produce sanitation.

Effects of Treatment with Electrolyzed Oxidizing Water on Postharvest Diseases of Avocado

The present study comprised five trials to investigate the efficacy of postharvest treatment with electrolyzed oxidizing (EO) water on postharvest disease development in avocado. Mature (dry matter 24–34%), hard green fruit cv. Hass (four trials), and cv. Wurtz (one trial) from orchards receiving minimal fungicide sprays were sourced, and subsequently dipped for 30 s in treatment solutions. Fruit were ripened at 23 °C and 65% relative humidity to encourage postharvest disease development, and assessed when ripe for anthracnose and stem end rot (SER), arising from natural field infections and/or the size of lesions resulting from post-treatment inoculation with Colletotrichum siamense. In the case of natural infection, EO water treatment reduced severity of SER disease by 30–75% compared with water treated control fruit in all four trials where it was assessed. Reduction in severity of SER after Graduate A+ fungicide or hypochlorite (NaOCl) bleach treatment ranged from 60–88% or 25–50%, respectively, compared with water controls. Under extremely high anthracnose disease pressure, 20% v/v EO water, NaOCl, as well as Graduate A+ fungicide treatments were mostly ineffective. Treatments in the final trial were applied as overhead sprays in an experimental-scale packing line to simulate commercial conditions. This was the only trial where anthracnose (as well as SER) was significantly reduced in fruit by 20% v/v EO water (12–35%) and Graduate A+ (34%) compared with water control. In two trials with C. siamense-inoculated fruit, anthracnose lesion size was reduced by 68–85%, and 90–100% by 20% v/v EO water and Graduate A+, respectively, compared with water-treated fruit. Fruit firmness and the number of days to ripen were mostly not affected by the treatments. This study demonstrates the potential for electrolyzed oxidizing water to be incorporated into integrated management programs for postharvest diseases of avocado, and possibly other fresh produce.

Cleaning and Bacteria Removal in Milking Systems by Alkaline Electrolyzed Oxidizing Water with Response Surface Design

Abstract. A wash cycle using an alkaline solution with a dissolved chemical detergent is a standard clean-in-place (CIP) process for cleaning milking systems. However, long-term chemical use may corrode equipment and create difficulties in wastewater treatment. This study investigated the potential for using alkaline electrolyzed oxidizing (EO) water as an alternative to alkaline chemical detergent for removal of microorganisms and adenosine triphosphate (ATP) on milking system materials. Laboratory trials were performed based on a Box-Behnken response surface design to assess the cleaning effect of alkaline EO water on three materials typically used in milking systems: stainless steel, rubber gasket, and polyvinyl chloride (PVC) hose. Results showed that alkaline EO water treatment was generally enhanced with increased treatment time, temperature, and pH, and their interaction effects were also observed in ATP removal. However, treatment time did not have a dominant role in cleaning PVC hose. Response surface models were developed to reliably predict detected microorganisms and relative light units (RLU) on the three materials after alkaline EO water treatment. Based on the response surface models, the three parameters for alkaline EO water cleaning were optimized as treatment time of 10.0 min, temperature of 61.8°C, and pH of 12, after which microorganisms and RLU were nearly undetectable. Alkaline EO water treatment with the optimized parameters had an equivalent or better cleaning ability compared to the commercial detergent, suggesting its potential as a cleaning and bacteria removal agent for milking systems. Keywords: Alkaline electrolyzed oxidizing water, Cleanliness, Milking system, Response surface model.

Viability assay of E. coli O157: H7 treated with electrolyzed oxidizing water using flow cytometry

Bacteria treated with chlorine-based sanitizer could enter into viable but non-culturable (VBNC) state, which may be underestimated its health risk. In this study, E. coli O157: H7 was treated with slightly acidic electrolyzed water (SAEW), acidic electrolyzed water (AEW) and sodium hypochlorite with different available chlorine concentrations (ACC). The reduction of population was determined, as well as the status of treated cells (viable and culturable, VBNC, dead) was assayed using flow cytometry combined with plate counting. Finally, the cell which cannot be detected using routine media was cultured in p-TSB to resuscitate. The results showed that the reduction of E. coli O157: H7 increased with increasing ACC of SAEW, AEW and sodium hypochlorite and the antimicrobial effect of electrolyzed oxidizing (EO) waters was much higher than sodium hypochlorite. SAEW, AEW and sodium hypochlorite with ACC of 30, 20 and 60 mg/L achieved E. coli O157: H7 colonies to non-detectable level on solid media. The results obtained from flow cytometric assay indicated that culturable cells after EO water and sodium hypochlorite treatments with increasing ACC firstly enter VBNC state and then transferred to dead status. VBNC E.coli was able to be resuscitated in p-TSB and therefore regarded as a potential risk for human health. E. coli O157: H7 in VBNC state after EO water treatment should be taken into consideration and complete inactivation could be achieved by elevated chlorine concentration.

Effectiveness of electrolyzed oxidizing water treatment in removing pesticide residues and its effect on produce quality

This study evaluated the effects of electrolyzed oxidizing (EO) water treatment on the removal of pesticide residues (diazinon, cyprodinil and phosmet) from spinach, snap beans and grapes, and the effect on produce quality. High available chlorine content (ACC) and long treatment time of EO water resulted in high pesticide removals. Up to 59.2, 66.5 and 37.1% of diazinon; 43.8, 50.0 and 31.5% of cyprodinil; 85.7, 73.0 and 49.4% of phosmet; were removed from spinach, snap beans and grapes, respectively, after 15min EO water treatment at 120mg/l ACC. EO water was also more effective than electrolyzed reduced water, bleach, VegWash and DI water on pesticide removal. In addition, no significant colour or texture deterioration were found on produce samples treated with EO water. It was concluded, EO water can be very effective in pesticide residue removal from fresh produce without affecting the produce quality.

Efficacy of electrolyzed oxidizing water as a pretreatment method for reducing Listeria monocytogenes contamination in cold-smoked Atlantic salmon (Salmo salar)

Listeria monocytogenes contamination in ready-to-eat (RTE) fish products, in particular in cold-smoked salmon is an important food safety concern. This study evaluated the antimicrobial activity of electrolyzed oxidizing (EO) water as a pretreatment method during the process of cold-smoked salmon to inactivate L. monocytogenes. In addition, the effect of EO water treatment on the sensory and textural quality of the final product was also evaluated. Raw Atlantic salmon (Salmo salar) fillets were inoculated with L. monocytogenes (with an approximately cell number of 6 × 105 CFU/g L. monocytogenes ATCC 19114) and treated with EO water at three different temperatures (20, 30, and 40 °C) and at three different exposure time of 2, 6, and 10 min before the cold-smoking process. A combination of EO water and a mild temperature (40 °C) had reduced L. monocytogenes populations by 2.85 log10 CFU/g. The sensory as evaluated by a consumer panel (N = 71) and texture, which was measured by texture analysis showed no significant changes between EO and mild temperature treated samples and the control.

Effect of Electrolyzed Oxidizing Water Treatment on the Reduction of Nitrite Levels in Fresh Spinach during Storage

Leafy vegetables are the major source of nitrite intake in the human diet, and technological processing to control nitrite levels in harvested vegetables is necessary. In the current work, the effect of electrolyzed oxidizing water (EOW) on the nitrite and nitrate levels in fresh spinach during storage was studied. EOW treatment, including slightly acidic electrolyzed water and acidic electrolyzed water, was found to effectively reduce nitrite levels in fresh spinach during storage; levels in the late period were 30 to 40% lower than that of the control. However, the nitrate levels in fresh spinach during storage were not influenced by EOW treatment. The reduction of nitrite levels in EOW-treated fresh spinach during storage can be attributed to the inactivation of nitrate reductase directly and to the reduction of bacterial populations. Our results suggest that treatment with slightly acidic electrolyzed water may be a better choice to control nitrite levels in fresh vegetables during storage. This study provided a useful method to reduce nitrite levels in fresh spinach.

Optimization and modeling of an electrolyzed oxidizing water based Clean-In-Place technique for farm milking systems using a pilot-scale milking system

Electrolyzed oxidizing (EO) water has been recommended to be used as a cleaning and sanitizing agent for Clean-In-Place (CIP) of on-farm milking systems. The CIP process for milking system with EO water was optimized using a pilot-scale pipeline milking system. The milking system was soiled using raw milk inoculated with four common microorganisms found in milk and cleaned using EO water. The cleaning effectiveness of the EO water treatment was evaluated by ATP bioluminescence test and microbiological analysis through enrichment culture. The effect of different temperatures of the alkaline EO water (45–75°C) and acidic EO water (25–45°C) were investigated. A generalized mathematical model was built and validated for the pilot scale milking system as well as compared with the conventional CIP technique. This study indicated that the EO water CIP outperformed the conventional CIP, indicating that it has a potential to be used in commercial dairy farms.

Influence of nalidixic acid adaptation on sensitivity of various Shiga toxin-producing Escherichia coli to EO water treatment

This study was designed to validate the use of nalidixic acid-adapted strains of various STEC for electrolyzed oxidizing (EO) water efficacy testing. The resistance of total 48, parent (NalS) and adapted (NalA) strains of Escherichia coli O157:H7 and six major serotypes of non-O157, STEC were tested against EO water using minimum inhibitory concentration (MIC) and inoculated beef trims. MIC was 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. While, beef trims (5 cm cubes) were inoculated with a cocktail of the same serogroup strains and treated with EO water (50 mg/L available chlorine) for 1 min. The MIC values of individual strains ranged from 0.41 to 1.66 mg/L free chlorine of EO water. When treated on beef trim, pathogen load reductions ranging from 0.44 to 1.54 log CFU/cm2 were observed. No significant differences in sensitivity towards EO water treatment were observed between NalS and their NalA derivatives in either study which validates the use of NalA strains in EO water efficacy study. In addition, the EO water treatment that reduced E. coli O157:H7 was equally or more effective in reducing non-O157 STEC on beef trim.

Product Identification and Safety Evaluation of Aflatoxin B1 Decontaminated by Electrolyzed Oxidizing Water

In this study with aflatoxin-contaminated peanuts, the effectiveness of electrolyzed oxidizing water (EOW) in the decontamination of aflatoxin B(1) was investigated. The aflatoxin B(1) content was markedly reduced upon treatment with EOW, particularly with neutral electrolyzed oxidizing water (NEW). The conversion product of EOW treatment was isolated and identified as 8-chloro-9-hydroxy aflatoxin B(1) (compound 1), which is an amphiphilic molecule, in contrast to fat-soluble aflatoxin B(1). A mutagenic response study revealed that the number of revertants per plate after treatment of bacterial strains TA-97, TA-98, TA-100, and TA-102 with NEW was within the standard value range. The HepG2 cell viability assay yielded an IC(50) value of compound 1 approximately 150 mM. This study indicates that EOW had the ability to decontaminate aflatoxin B(1), and the conversion product, compound 1, did not exhibit mutagenic activity or cytotoxic effects.

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.

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

Listeria monocytogenes and Morganella morganii have been implicated in listeriosis outbreaks and histamine fish poisoning, respectively. Possible sources of contamination of food products include processing equipment, food handlers, and fish smokehouses. Treatment of food preparation surfaces and of whole fish during handling with agents such as, electrolyzed oxidizing (EO) water, could reduce biofilm formation on seafood products and in seafood processing plants. We examined the efficacy of EO water against L. monocytogenes and M. morganii biofilms using the MBEC™ Assay System (Innovotech Inc.), conveyor belt coupons, and raw fish surfaces. The MBEC™ Assay System was used to assess the activity of EO water against 24-h biofilms of 90 L. monocytogenes strains and five M. morganii strains. Biofilms were exposed to PBS or EO water for 0 (control), 5, 15, and 30 min. All bacterial isolates were susceptible (reduction of 7 log10CFU) to treatment with EO water for 5 min based on results obtained using this assay system. EO water was used to treat four L. monocytogenes strains and one M. morganii strain attached to conveyor belt coupons and fish surfaces. Three L. monocytogenes strains and one M. morganii strain on belt coupons were reduced by 1–2.5 log10CFU/cm2 by exposure (5 min) to EO water compared to exposure to sterile distilled water. Strain to strain variability in susceptibility to EO water was evidenced by the fact that numbers of one L. monocytogenes strain were not reduced by EO water treatment of belt surfaces. EO water was not effective against L. monocytogenes and M. morganii on fish surfaces as growth occurred during cold storage. These results suggest that exposure of conveyor belts to EO water for a minimum of 5 min could assist in the removal of some biofilms. Removal of food residue with continuous or intermittent spraying of food processing equipment (e.g., conveyor belts, slicers) could reduce or prevent further biofilm formation. Additional sanitizers must be investigated for activity against bacteria associated with raw fish.

Effects of Electrolyzed Oxidizing Water Treatment on Reducing Vibrio parahaemolyticus and Vibrio vulnificus in Raw Oysters

Contamination of Vibrio parahaemolyticus and Vibrio vulnificus in oysters is a food safety concern. This study investigated effects of electrolyzed oxidizing (EO) water treatment on reducing V. parahaemolyticus and V. vulnificus in laboratory-contaminated oysters. EO water exhibited strong antibacterial activity against V. parahaemolyticus and V. vulnificus in pure cultures. Populations of V. parahaemolyticus (8.74 × 107 CFU/ml) and V. vulnificus (8.69 × 107 CFU/ml) decreased quickly in EO water containing 0.5% NaCl to nondetectable levels (>6.6 log reductions) within 15 s. Freshly harvested Pacific oysters were inoculated with a five-strain cocktail of V. parahaemolyticus or V. vulnificus at levels of 104 and 106 most probable number (MPN)/g and treated with EO water (chlorine, 30 ppm; pH 2.82; oxidation-reduction potential, 1131 mV) containing 1% NaCl at room temperature. Reductions of V. parahaemolyticus and V. vulnificus in oysters were determined at 0 (before treatment), 2, 4, 6, and8hof treatment. Holding oysters inoculated with V. parahaemolyticus or V. vulnificus in the EO water containing 1% NaCl for 4 to 6 h resulted in significant (P < 0.05) reductions of V. parahaemolyticus and V. vulnificus by 1.13 and 1.05 log MPN/g, respectively. Extended exposure (>12 h) of oysters in EO water containing high levels of chlorine (>30 ppm) was found to be detrimental to oysters. EO water could be used as a postharvest treatment to reduce Vibrio contamination in oysters. However, treatment should be limited to 4 to6hto avoid death of oysters. Further studies are needed to determine effects of EO water treatment on sensory characteristics of oysters.

Efficacy of Ozonated and Electrolyzed Oxidative Waters To Decontaminate Hides of Cattle before Slaughter

The hides of cattle are the primary source of pathogens such as Escherichia coli O157:H7 that contaminate preevisceration carcasses during commercial beef processing. A number of interventions that reduce hide contamination and subsequent carcass contamination are currently being developed. The objective of this study was to determine the efficacy of ozonated and electrolyzed oxidizing (EO) waters to decontaminate beef hides and to compare these treatments with similar washing in water without the active antimicrobial compounds. Cattle hides draped over barrels were used as the model system. Ozonated water (2 ppm) was applied at 4,800 kPa (700 lb in2) and 15°C for 10 s. Alkaline EO water and acidic EO water were sequentially applied at 60°C for 10 s at 4,800 and 1,700 kPa (250 lb in2), respectively. Treatment using ozonated water reduced hide aerobic plate counts by 2.1 log CFU/100 cm2 and reduced Enterobacteriaceae counts by 3.4 log CFU/100 cm2. EO water treatment reduced aerobic plate counts by 3.5 log CFU/100 cm2 and reduced Enterobacteriaceae counts by 4.3 log CFU/100 cm2. Water controls that matched the wash conditions of the ozonated and EO treatments reduced aerobic plate counts by only 0.5 and 1.0 log CFU/100 cm2, respectively, and each reduced Enterobacteriaceae counts by 0.9 log CFU/100 cm2. The prevalence of E. coli O157 on hides was reduced from 89 to 31% following treatment with ozonated water and from 82 to 35% following EO water treatment. Control wash treatments had no significant effect on the prevalence of E. coli O157:H7. These results demonstrate that ozonated and EO waters can be used to decontaminate hides during processing and may be viable treatments for significantly reducing pathogen loads on beef hides, thereby reducing pathogens on beef carcasses.

CLEANING MILKING SYSTEMS USING ELECTROLYZED OXIDIZING WATER

Electrolyzed oxidizing (EO) water is a novel cleaning and disinfecting agent, produced by separating a weak sodium chloride solution into alkaline and acidic components. A pilot-scale pipeline milking system was soiled using raw milk inoculated with common microorganisms. The milking system was then washed with alkaline EO water followed by acidic EO water. After cleaning, the effectiveness of the EO water treatment was evaluated by ATP bioluminescence and microbiological analysis. A 10 min wash with 60°C alkaline EO water followed by a 10 min wash with 60°C acid EO water successfully removed all detectable bacteria and ATP from the non-porous milk contact surfaces. Shorter treatment times (5 and 7.5 min) with EO water were also evaluated, along with a control treatment using conventional dairy cleaning chemicals. There were no significant differences between the 10 min and 7.5 min EO water treatments and the conventional treatment. In a longer-term soiling-washing simulation, only the 7.5 min EO water treatment was evaluated after ten soiling and cleaning cycles, and it was

Efficacy of electrolyzed oxidizing water for the microbial safety and quality of eggs

During commercial processing, eggs are washed in an alkaline detergent and then rinsed with chlorine to reduce dirt, debris, and microorganism levels. The alkaline and acidic fractions of electrolyzed oxidizing (EO) water have the ability to fit into the 2-step commercial egg washing process easily if proven to be effective. Therefore, the efficacy of EO water to decontaminate Salmonella Enteritidis and Escherichia coli K12 on artificially inoculated shell eggs was investigated. For the in vitro study, eggs were soaked in alkaline EO water followed by soaking in acidic EO water at various temperatures and times. Treated eggs showed a reduction in population between > or = 0.6 to > or =2.6 log10 cfu/g of shell for S. Enteritidis and > or =0.9 and > or =2.6 log10 for E. coli K12. Log10 reductions of 1.7 and 2.0 for S. Enteritidis and E. coli K12, respectively, were observed for typical commercial detergent-sanitizer treatments, whereas log10 reductions of > or =2.1 and > or =2.3 for S. Enteritidis and E. coli K12, respectively, were achieved using the EO water treatment. For the pilot-scale study, both fractions of EO water were compared with the detergent-sanitizer treatment using E. coli K12. Log10 reductions of > or = 2.98 and > or = 2.91 were found using the EO water treatment and the detergent-sanitizer treatment, respectively. The effects of 2 treatments on egg quality were investigated. EO water and the detergent-sanitizer treatments did not significantly affect albumen height or eggshell strength; however, there were significant affects on cuticle presence. These results indicate that EO water has the potential to be used as a sanitizing agent for the egg washing process.

INACTIVATION OF LISTERIA MONOCYTOGENES BIOFILMS BY ELECTROLYZED OXIDIZING WATER

This study investigates the resistance of Listeria monocytogenes biofilms on stainless steel surfaces to electrolyzed oxidizing (EO) water. A direct agar overlay method was used to estimate the attached bacteria on stainless steel coupons after an EO water treatment. A scraping method was also used to quantify the adherent cell populations after the EO water treatment. The stainless steel surface allowed 10 to 15% of the surface area to be covered by Listeria biofilm when the inoculated stainless steel coupon was incubated in 10% tryptic soy broth (TSB) at 23C for 48 h. When the stainless steel coupons containing adherent cells were treated with EO water (56 mg/L of residual chlorine) for 10, 30, 60, 180, and 300 s, adherent cell populations (10.3 log10 CFU/coupon) were reduced with increasing treatment time. Although the direct agar overlay methods do not quantify survival of single bacteria, only one to five cell clumps per coupon survived after 300 s of the EO water treatment. Using the scraping method, the adherent cell population on the stainless steel coupons was reduced by about 9 log cycles after 300 s of EO water treatment.

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 log 10 reductions were achieved after 10 s of ROX EO water treatment. B. cereus spores were the most resistant pathogen. However, more than 3 log 10 reductions were achieved with 120-s EO water treatment.