Article

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

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Abstract

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.

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... As shown in Figure 7, no bactericidal effect against each microorganism was observed, even after 5 min of treatment time. This result suggests the potential risk that alkaline sanitizers, such as sodium bicarbonate solution [72] and neutral electrolyzed water (NEW) [73], are ineffective to these microorganisms. However, if the alkaline sanitizers contain other biocidal reagents, the bactericidal effect should be expected because these microorganisms were inactivated by 2 and 5 ppm sodium hypochlorite solutions, with pH values of 7.68 and 8.19, respectively (Figure 4). ...
... However, if the alkaline sanitizers contain other biocidal reagents, the bactericidal effect should be expected because these microorganisms were inactivated by 2 and 5 ppm sodium hypochlorite solutions, with pH values of 7.68 and 8.19, respectively (Figure 4). NEW seems to be an effective sanitizer against these microorganisms because it contains HOCl and − OCl [73]. was observed, even after 5 min of treatment time. ...
... was observed, even after 5 min of treatment time. This result suggests the potential risk that alkaline sanitizers, such as sodium bicarbonate solution [72] and neutral electrolyzed water (NEW) [73], are ineffective to these microorganisms. However, if the alkaline sanitizers contain other biocidal reagents, the bactericidal effect should be expected because these microorganisms were inactivated by 2 and 5 ppm sodium hypochlorite solutions, with pH values of 7.68 and 8.19, respectively (Figure 4). ...
Article
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Disinfection and sterilization against cold-tolerant microorganisms are very important for enhancing food safety and hygiene management under refrigeration conditions. We isolated Exiguobacterium sp. and Pantoea sp. from an immersion solution of packed tofu and evaluated their growth properties and sensitivities to various bactericidal methods. These microorganisms were classified as psychrotrophic bacteria, according to their ability to grow at 4 °C, with an optimum growth temperature of 30 °C. Exiguobacterium sp. and Pantoea sp. were more sensitive to heat and sodium hypochlorite than Escherichia coli (E. coli). Exiguobacterium sp. was sensitive to acetic acid and citric acid, while Pantoea sp. was relatively insensitive and E. coli was insensitive to these organic acids. All microorganisms used in this study were resistant to sodium hydroxide solution (pH 8.00). Exiguobacterium sp. showed resistance to ozonated water and UV; therefore, particular attention should be paid to the contamination of this microorganism in food factories. Both Exiguobacterium sp. and Pantoea sp. were inactivated by pulsed electric field (PEF) treatment that did not cause lethal damage to E. coli. The results obtained in this study suggest that the bactericidal methods targeting the fragile cell membrane with high permeability are effective for the inactivation of cold-tolerant microorganisms.
... We used a pool of 5 native different Salmonella serovars while Park et al. (2008) used 3 reference strains of S. Typhimurium. Other authors evaluated the effectiveness of EW for longer exposure times and reported similar or even lower bacterial reductions (Abadias, Usall, Oliveira, Alegre, & Viñas, 2008;Koseki et al., 2003;Stopforth, Mai, Kottapalli, & Samadpour, 2016). Abadias et al. (2008) evaluated the bactericidal activity of EW (containing approximately 50 ppm of free chlorine) against Salmonella on lettuce and reported that exposure times of 1 and 3 min caused reductions of 1-2 log CFU/g with no significant differences between the exposure times analyzed. ...
... Other authors evaluated the effectiveness of EW for longer exposure times and reported similar or even lower bacterial reductions (Abadias, Usall, Oliveira, Alegre, & Viñas, 2008;Koseki et al., 2003;Stopforth, Mai, Kottapalli, & Samadpour, 2016). Abadias et al. (2008) evaluated the bactericidal activity of EW (containing approximately 50 ppm of free chlorine) against Salmonella on lettuce and reported that exposure times of 1 and 3 min caused reductions of 1-2 log CFU/g with no significant differences between the exposure times analyzed. Stopforth et al. (2016) evaluated EW (50 ppm) in leafy greens (organic baby lettuces, organic red and green chard, organic mizuna, organic arugula, organic friseé, and organic radicchio) and demonstrated that after 60 or 90 s of exposure Salmonella reductions were 2.0-2.5 log CFU/g, with no significant difference between the two exposure times analyzed. ...
... After 1 min of exposure time, the samples inoculated with the dip method resulted in a 1 log CFU/g reduction of Salmonella populations, samples inoculated by spot inoculation of the inner surface of the lettuce leaf reduced approximately 2.5 log CFU/g while the spot inoculation of the outer surface of the lettuce leaf resulted in approximately 4.6 log CFU/g. We used spot inoculation, Abadias et al. (2008) used dip inoculation and Stopforth et al. (2016) used spray inoculation, none made distinctions between leaf surface sites method. Based on Koseki et al. (2003) findings, the lower reduction reported by Abadias et al. (2008) could be due to the inoculation method. ...
Article
EW has been proposed as a sanitization method for home use to reduce chemical and biological hazards in fresh products. Most studies have evaluated exposure times of 1–10 min which may be too long for processing fresh produce. The aim of this work was to evaluate if short exposure times (15, 30 or 45 s) to electrolyzed water (EW – 50 ppm of free chlorine) were enough to significantly reduce Salmonella spp counts and Imidacloprid concentrations in lettuce. Results showed that EW treatment of 45 s achieved a reduction of 4 log CFU/g in the Salmonella spp counts and a reduction of 48,57% in Imidacloprid concentrations. As to quality parameters, neither texture profile nor flavor were affected by the treatment. The fact that only 45 s were enough to effectively reduced Salmonella spp and Imidacloprid makes the EW treatment an ideal sanitization method for lettuce in both the industry and the household.
... EW is generated as water goes through the anodes of a membrane-based electrolyser. 9 The resulting solution stands out as an advantageous method due to its low production cost and environmentally friendly approach, mostly because there have been no health issues reported due to this treatment for the past few years. 10,11 EW is also known to be very efficient for the disruption of bacterial biofilm matrices. ...
... Unlike NaClO solutions, where the pH is between 11.00 and 12.00, presenting more difficult handling, exposing the operator and the machinery to an alkalinity solution generally higher than pH 11.00. 6 Finally, EW has the main biocidal reagents HOCl, ClO − , HO 2 and superoxide radicals, as described by Abadias et al. 9 Another advantage of EW is its application in neutral solutions, since some of its compounds are efficient even at neutral pH. 11,13 Because of the advantages with the efficacy of EW as a sanitizer in the food and agriculture industry to reduce or eliminate bacterial and fungus from food, in the United States, EW has been approved for use in the food industry by the US Environmental Protection Agency. ...
... 10 However, to date, no studies have been carried out on the application of EW in sanitizing citrus fruits. 9 Here, we evaluated the efficacy of EW to inhibit X. citri growth, and its potential to reduce the population of X. citri on the surface of contaminated citrus fruit. Our results fully support the use of EW as an effective sanitizer alternative to the NaClO solutions used in packinghouses at present, being considered less toxic, less corrosive, and safer to be handled. ...
Article
BACKGROUND The largest and most profitable market for citrus is the production of fresh fruit. Xanthomonas citri subsp. citri is a Gram‐negative plant pathogen and the etiological agent of citrus canker, one of the major threats to citrus production worldwide. In the early stages of infection, X. citri can attach to plant surfaces by means of biofilms. Biofilm is considered an essential virulence factor, which helps tissue colonization in plants. Thus, sanitization of citrus fruit is mandatory in packinghouses before any logistic operation as packing and shipment to the market. The aim of this study was to evaluate electrolysed water (EW) as a sanitizer for the disinfection of citrus fruit in packinghouses. RESULTS Using a protocol to monitor cell respiration we show that EW, obtained after 8 and 9 min of electrolysis, sufficed to kill X. citri when applied at a concentration of 500 μL mL⁻¹. Furthermore, microscopy analysis, combined with time‐response growth curves, confirmed that EW affects the bacterial cytoplasmatic membrane and it leads to cell death in the first few minutes of contact. Pathogenicity tests using limes to simulate packinghouse treatment showed that EW, produced with 9 min of electrolysis, was a very effective sanitizer capable of eliminating X. citri from contaminated fruit. CONCLUSION It was possible to conclude that EW is significantly effective as sodium hypochlorite (NaClO) at 200 ppm. Therefore, EW could be an alternative for citrus sanitization in packinghouses. © 2020 Society of Chemical Industry
... F. carica is an important source of minerals (such as calcium, vitamin K, manganese, potassium, magnesium, and copper), protein, vitamins, and carbohydrates (4) and the leaves (primary and processed form) have been harnessed for production However, information regarding the biosafety of F. carica leaves is limited as majority of the research works on histological effect of the plant were conducted on induce-damaged liver (10) and heart of Albino rat (11), using chemicals such as tetrachloride and doxorubicin respectively. In order to justify its promising preservative feature as an alternative to chemical preservatives whose resurgence has been implicated in food storage (12)(13)(14), there is need to investigate the safety of this plant (leaf). To the best of our knowledge, this is the first study reporting the in-vivo safety of F. caraca leaf extracts. ...
... Over the years, chemical preservatives are employed for controlling microbial growth and reducing foodborne disease (FBD) incidences, owing to their effectiveness against spoilage microbes; however, their resurgence has been implicated in food storage (12)(13)(14). Hence, there is a growing body of research on medicinal plants such as F. carica for eliminating foodborne pathogens as safe and natural remedies, thereby reducing the risk of FBD incidences while assuring consumers with safe food product (18). ...
Article
Full-text available
Due to the global disturbance of chemical resurgence in food, Fig leaves (Ficus carica) had been made to be applied as preservatives to extend the shelf life of perishable foods and to address chemical toxicity concern, despite limited information regarding its biosafety. Hence, the need to affirm the safety of this plant in-vivo was studied. Extracts of Fig leaves were mixed with basal diet and used as feed for one group of Wistar albino rats (treated group) while the second group was fed with sole basal medium to serve as control. The blood samples of both groups were taken before the rats were subjected to cervical dislocation. Haematological and histological parameters were studied to know the effects of the extracts and in order to justify the usage of plant extracts as preservatives for perishable foods. The haematological parameters of the treated group were higher than the control except for the insignificant changes in lymphocytes, basophils and eosinophils. Furthermore, the histological study revealed no sign of lesions in the all organs examined from both groups. The adoption of Fig leaf as preservatives has no contra-indication on the organs or blood parameters. Hence the global adoption as alternative preservative agents is undoubtedly recommended. Citation: Bankefa OE, Gabriel-Ajobiewe AR, Ajayi OE, Ayilara-Akande SO, Oladeji SJ, Kayejo GV. Biosafety assessment of fig (ficus carica) leaves, an alternative preservative agent. J food safe & hyg 2019; 5(3):131-136
... and S. aureus were obtained from Bioresource Collection and Research Center (BCRC, Hsinchu, Taiwan). The preparation and culture of the testing microorganisms based on the previous research (Abadias et al., 2008). ECHC (BCRC 14824), Salmonella enterica (BCRC12947) and S. aureus (BCRC 10451) pure culture collections were transferred and grown on tryptic soy agar (TSA, BD, N.J., USA) incubating at 37 ± 1℃ for 48 hours. ...
... The MLEW reveals comparable even stronger antimicrobial effects with NaOCl in our study. The same trend could also be observed in previous studies of neutral electrolyzed water (Abadias et al., 2008;Machado et al., 2016). The antimicrobial property of MLEW is contributed to multiple factors. ...
Article
Full-text available
The membrane-less electrolyzed water (MLEW) has been reported to possess antimicrobial effects against a variety of microorganisms and is considered as an alternative of traditional disinfectants. In the study, the inactivating efficiency was evaluated by using MLEW with free available chlorine (FAC) at concentrations of 50 and 100 mg/L against food-borne related microorganisms, including Enterohaemorrhagic Escherichia coli (ECHC), Salmonella spp. and Staphylococcus aureus individually. D-value (decimal reduction time) was applied for evaluating the antimicrobial ability of MLEW. D-values of ECHC, Salmonella, and S. aureus were about 120 sec, 5 sec and 5 sec, respectively. Our study demonstrated that MLEW is very effective in reducing the food-borne microbial contamination.
... Both ECAW and ozone are effective sanitizers for inactivating foodborne pathogens (Abadias, Usall, Oliveira, Alegre, & Vinas, 2008;Ayebah, Hung, & Frank, 2005;Ayebah, Hung, Kim, & Frank, 2006;Deza et al., 2003Deza et al., , 2005Deza et al., , 2007Emer et al., 2008;Guentzel et al., 2008;Hricova et al., 2008;Pascual et al., 2007;Vurma et al., 2009), but the equipment for generating ECAW or ozonation is typically quite large and expensive for applications at households and small business. In addition, the relative short shelf life of the sanitizing solutions generated may also limit their application in small scale. ...
... Even this S can not be generated into effective sanitizing components. Although the effectiveness of electrolyzed water has been widely documented in the literature (Abadias et al., 2008;Ayebah et al., 2005;Ayebah et al., 2006;Deza et al., 2003Deza et al., , 2005Deza et al., , 2007Guentzel et al., 2008;Issa-Zacharia, Kamitani, Morita, & Iwasaki, 2010;Kim et al., 2003;Kiura et al., 2002;Koseki & Itoh, 2000;Liao, Chen, & Xiao, 2007;Liu, Duan, & Su, 2006;Oomori, Oka, Inuta, & Arata, 2000;Yang, Swem, & Li, 2003), these waters were generated by relatively large equipment with high power, and had been electrolyzed sufficiently, thus can have sufficient sanitizing effects. One possible reason could be that the electrical power delivered by I was not sufficient to cause electrolysis. ...
Article
Electrochemically activated water (ECAW), also known as electrolyzed water, and ozonized water are typically effective in inactivating bacteria, but their generation typically uses high current and voltage. A few simpler antimicrobial technologies that are also based on the application of a mild electrical current have been recently marketed to food retail and service customers claiming to have sanitizing properties for controlling bacteria. The objective of this study was to determine the sanitizing effect of some of these commercial technologies on Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica and compare them with sterile water, generated ECAW generated with a pilot size electrolyzing unit, and salt solutions sprayed using commercial device sprays. A concentration of 100 mg/L ECAW had sanitizing effects of at least 5 log CFU/mL reductions on liquid culture and more than 4 log CFU/coupon reductions for E. coli O157:H7, L. monocytogenes and Salmonella dried on stainless steel surface, respectively. No bacterial cells were detected by direct plate counting post-ECAW treatment. In contrast, the treatment of liquid cultures with any of the commercial technologies tested resulted in non-significant bacterial cell reductions greater than 0.5 log CFU/mL. Similarly, when cells had been dried on metal surfaces and treated with any of the water generated with those technologies, no reductions were observed. When the manufacturer's instructions were followed, the reduction of cells on surface was largely due to the physical removal by cloth-wiping after water fraction application. These results indicate that treatment with any of these portable technologies had no noticeable antimicrobial activity. These results would be helpful for guiding consumers when choosing a right sanitization to ensure food safety.
... EW is considered environmental-friendly sanitizer because it is generated from dilute salt and water, cause less corrosion to surface of production plant and eliminate the effect to human body. [6]- [8] This paper serves as a systematic review on the recent progress of the application of EW as a sanitizer in food industry. It reviewed the efficacy of EW on major foodborne pathogens and foodborne spoilage microorganisms, the antimicrobial mechanism of EW on microorganisms, factors that affect the antimicrobial efficacy of EW application and the effect of EW on food quality. ...
... Its neutral pH may pose less negative effect on human health and environment hence it receives many interest in recent years. [6] Low concentration Electrolyzed Water. (ACC < 10 ppm, LcEW) LcEW is often produced by electrolyzing a diluted NaCl solution with water in an EW generator that has no separate membrane. ...
... and S. aureus were obtained from Bioresource Collection and Research Center (BCRC, Hsinchu, Taiwan). The preparation and culture of the testing microorganisms based on the previous research (Abadias et al., 2008). ECHC (BCRC 14824), Salmonella enterica (BCRC12947) and S. aureus (BCRC 10451) pure culture collections were transferred and grown on tryptic soy agar (TSA, BD, N.J., USA) incubating at 37 ± 1℃ for 48 hours. ...
... The MLEW reveals comparable even stronger antimicrobial effects with NaOCl in our study. The same trend could also be observed in previous studies of neutral electrolyzed water (Abadias et al., 2008;Machado et al., 2016). The antimicrobial property of MLEW is contributed to multiple factors. ...
... The results were in agreement with previous reports that microorganisms in attached state were resistant to various sanitisers (Kim et al., 2007;Peta, Lindsay, Broezel, & von Holy, 2003). When NEW (50 mg/L FAC) was applied to microorganisms inoculated on vegetable, the reduction was much less than that in pure cultures (Abadias et al., 2008). The survival population of cells in suspension was also detected (Table 1). ...
Article
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 mg/mL of protein leakage were observed for E. coli ATCC 25922 and P. pastoris GS115, respectively after 3 min combination treatment, while 6.22 mg/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.
... Samples were homogenized in a Stomacher 400 circulator blender (Seward Ltd, Worthing, West Sussex, UK) at 230 rpm for 2 minutes. 79,80 To remove particular matter, homogenate was poured into a filter bag with 0.5 mm pores (Seward Ltd, Worthing, West Sussex, UK). Aliquots of filtered homogenate were pipetted into 2 mL microcentrifuge safe-lock tubes (Eppendorf, Fisher Scientific, Pittsburgh, PA) and placed in a −80°C freezer for long-term storage before DNA extraction. ...
Article
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Many patients with alcohol use disorder (AUD) consume alcohol chronically and in large amounts that alter intestinal microbiota, damage the gastrointestinal tract, and thereby injure other organs via malabsorption and intestinal inflammation. We hypothesized that alcohol consumption and subsequent abstinence would change the gut microbiome in adults admitted to a treatment program. Stool and oral specimens, diet data, gastrointestinal assessment scores, anxiety, depression measures and drinking amounts were collected longitudinally for up to 4 weeks in 22 newly abstinent inpatients with AUD who were dichotomized as less heavy drinkers (LHD, <10 drinks/d) and very heavy drinkers (VHD, 10 or more drinks/d). Next-generation 16 S rRNA gene sequencing was performed to measure the gut and oral microbiome at up to ten time points/subject and LHD and VHD were compared for change in principal components, Shannon diversity index and specific genera. The first three principal components explained 46.7% of the variance in gut microbiome diversity across time and all study subjects, indicating the change in gut microbiome following abstinence. The first time point was an outlier in three-dimensional principal component space versus all other time points. The gut microbiota in LHD and VHD were significantly dissimilar in change from day 1 to day 5 (p = .03) and from day 1 to week 3 (p = .02). The VHD drinking group displayed greater change from baseline. The Shannon diversity index of the gut microbiome changed significantly during abstinence in five participants. In both groups, the Shannon diversity was lower in the oral microbiome than gut. Ten total genera were shared between oral and stool in the AUD participants. These data were compared with healthy controls from the Human Microbiome Project to investigate the concept of a core microbiome. Rapid changes in gut microbiome following abstinence from alcohol suggest resilience of the gut microbiome in AUD and reflects the benefits of refraining from the highest levels of alcohol and potential benefits of abstinence.
... Abadias 19 showed that NEW (48 ppm of TC) could reduce more than 5.4-log CFU/mL of E. coli Results are expressed as mean ± standard deviation (n = 3). Different letters a, b, c in the same column indicate significantly different means (p<0.05). ...
Article
Full-text available
This study evaluated physicochemical and antibacterial properties of neutral electrolyzed water (NEW) produced by electrolyzing NaCl solutions. pH, total chlorine content (TC) and oxidation reduction potential (ORP) of NEW increased to equilibrium values when increasing NaCl concentration (0.20% - 1.5%) and electrolysis time (0 – 240 minute). The pH and ORP values increased sharply in the first 15-min of the electrolysis and then was stabilized in the ranges of 8.5-9.5 and 400-500 mV, respectively. Increasing NaCl concentration did not change the stabilized values of pH and ORP, but significantly increased (p<0.05) TC. Furthermore, we studied antibacterial activity of NEW against Escherichia coli and Salmonella enterica in suspension and in ground pork. Interestingly, 085% NaCl NEW after 10-min electrolysis reduced 7 log CFU/mL of E. coli and 2 log CFU/mL of S. enterica. This resistance of S. enterica toward NEW was possibly due to its biofilm-forming ability. Pdf available at: http://www.orientjchem.org/vol36no3/physicochemical-properties-and-bactericidal-effects-of-neutral-electrolyzed-water-against-escherichia-coli-and-salmonella-enterica-on-ground-pork/
... Electrolyzed water showed the best results in terms of lower weight loss, postharvest decay and microbial counts, while Berry Very ® negatively affected berry color, acidity level and firmness (Chiabrando et al. 2017). Abadías et al. (2008) indicated that diluted neutral electrolyzed water (50 mg/L free chlorine) has a bactericidal power against E. coli, Salmonella, Listeria innocua and Erwinia carotovara on fresh-cut lettuce, carrot, endive, corn salad, and four-season salad. ...
... Hypochlorous acid (HOCl) can diffuse through bacterial membrane and disrupt outer membrane A', internal membrane B, and bacterial proteins C. Alteration of bacterial DNA has been reported (Adapted from Rahman [20]). The use of EW has shown many advantages against other disinfectants; however, some reported limitations are short lifespan; AEW is corrosive [36] to metal [37] and leaves a salt residue on products affecting texture and taste. NEW has not shown these limitations [36]. ...
Article
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Food demand is increasing every year and, usually animal-derived products are generated far from consumer-places. New technologies are being developed to preserve quality characteristics during processing and transportation. One of them is electrolyzed water (EW) that helps to avoid or decrease the development of foodborne pathogens, or losses by related bacteria. Initially, EW was used in ready-to-eat foods such as spinach, lettuce, strawberries, among others; however, its application in other products is under study. Every product has unique characteristics that require an optimized application of EW. Different sanitizers have been developed; unfortunately, they could have undesirable effects like deterioration of quality or alterations in sensory properties. Therefore, EW is gaining popularity in the food industry due to its characteristics: easy application and storage, no corrosion of work surfaces, absence of mucosal membrane irritation in workers handling food, and it is considered environmentally friendly. This review highlights the advantages of using EW in animal products like chicken, pork, beef, eggs and fish to preserve their safety and quality.
... Another disinfecting compound that can be added to water is sodium hypochlorite (NaOCl), which is typically used as a disinfactant in home, health care and industrial settings. Solutions are effective for limiting the infectivity of a variety of viruses, bacteria and fungi [19][20][21]. There are also reports about disinfection efficacy against important animal pathogens, such as foot-and-mouth disease virus and African swine fever virus [22]. ...
Article
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Poor drinking water quality can affect pigs’ health and performance. The disinfection of water may enhance microbial water quality. In this study, bacteria and endotoxins in sodium hypochlorite-treated and -untreated water from one pig nursery were analyzed. Water samples were taken from incoming water and from compartments with treated and untreated water at the beginning and end of pipes and from nipples. The farm was visited 14 times to measure total bacteria counts and concentrations of Pseudomonas spp. and endotoxins. Additionally, the occurrence of coliform bacteria was analyzed. A mixed model analysis revealed significant reductions in total bacteria counts and Pseudomonas spp. in treated water at the beginning of pipes and at nipple drinkers. The differences between bacteria concentrations at the end of pipes had no clear trend. Endotoxin concentrations were approximately equal at the beginning of pipes and at nipple drinkers but were found to have differences at the end of pipes. The occurrence of coliform bacteria was significantly reduced in treated water. The application of sodium hypochlorite can significantly reduce bacteria in water pipes. Endotoxin concentrations were mostly unaffected by water treatment. Disinfection of the dead-end pipe sections failed, and thus these parts should be regarded as potential contamination sources.
... The ECAS has disinfection activity equivalent to 80% ethanol and is superior to 0.1% chlorhexidine or 0.02% povidone iodine (Tanaka, Fujisawa et al. 1999). However, previous applications of ECAS produced under strongly acidic conditions have been limited due to corrosion of processing equipment and phytotoxic effect on plants (Abadias, Usall et al. 2008, Guentzel, Lam et al. 2008, Cao, Zhu et al. 2009). Due to recent advancement in the technique for generating ECAS with slightly acidic pH (5-6.5), it has been widely used in sanitisation of vegetables with excellent efficacy (Koide, Takeda et al. 2009, Rahman, Ding et al. 2010, Hao, Liu et al. 2011. ...
Technical Report
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Executive Summary Environmental decontamination is a key management strategy to maintaining good respiratory herd health in piggeries. Actinobacillus pleuropneumoniae (A. pp) is one of the most important endemic respiratory pathogens of Australian pigs currently controlled by in-feed antibiotic medication and other bacterial species associated with porcine respiratory disease complex (PRDC) are important secondary pathogens. Livestock-associated MRSA has been identified as a major public health issue for intensive animal production, particularly for in-contact workers and their families. Disinfection of the farm environment to eliminate these pathogenic organisms remains a key component of disease control and production efficiency. Of the many disinfectants used in farm decontamination, quaternary ammonium compounds (QAC) have been shown to prevent aerosol transmission of A. pp in a previous CRC project. However, QAC and many other currently used disinfectants have significant drawbacks such as being hazardous to the environment and potentially toxic to animals and piggery workers, whilst also being responsible for co-selection of resistance to antibiotics (class 1 integrons, which are major drivers of the evolution of multidrug-resistance, always contain a QAC resistance gene in their structure). Therefore, in this project, an electrochemically activated solution (ECAS), an anolyte generated by electrolysing a dilute sodium chloride solution in a four-chamber electrolytic cell (Ecas4 Australia), was tested as an aerosol sanitiser. The Ecas4 anolyte has a neutral pH and is 100% safe; it is currently used for sanitisation of Legionella contamination in hospital water supplies, disinfection of dairy manufacturing equipment, and in seafood and fresh food produce as both a wash and dry fog. In vitro antimicrobial susceptibility testing of ECAS against field strains of A. pp representing the main serotypes and MRSA isolated from Australian pigs, confirmed that at very low concentrations of the anolyte in water (0.19-3.13% v/v or 0.48-7.8 ppm of active chlorine) ECAS was equally effective at killing both A. pp and MRSA within 30 s of exposure. SYBR green-dye-based real-time quantitative PCR was optimised to detect and quantify low levels of total bacteria and A. pp targeting the 16S rRNA and apxIVA genes, respectively, using previously published primer sets. Using the Coriolis air sampler device, the sample collection protocol to capture A. pp. from the farm environment was optimised and very low levels of A. pp (5.1×10 5 genomic units) were detected in both weaner rooms and grower/finisher sheds at a continuous flow farm with endemic pleuropneumonia. Furthermore, a novel step was ii introduced into the qPCR by treating samples with 50 µm propidium monoazide to differentially quantify live and dead bacterial cells in the sample, an ideal rapid quantitative assay for determining the effectiveness of aerosol disinfection methods. To examine the effectiveness of Ecas4 dry fogging in eliminating A. pp and other aerosolised bacteria, a proof-of-concept trial was conducted in a recently vacated weaner room at the same continuous flow piggery using a protocol adapted from Dr Peter McKenzie's Pork CRC project 2C-117. A 1-log10 reduction in total bacterial count was observed after the first hour of fogging, a 2-log10 reduction was observed after fogging for two and three hours, while 99.9% (3.7-log10) of total bacteria were effectively inactivated by Ecas4 dry fogging after five hours of discontinuous treatment. However, since we were not able to conduct fogging trials with pigs in the weaner room, due to the potential for creating a large number of immunologically naïve animals entering the high-risk environment of the grower shed, we could not capture A. pp. from the weaner room environmental air samples. Hence, disinfection efficacy on farm against A. pp could not be determined. Nevertheless, the pilot results with total bacteria are encouraging enough to upscale to a much larger trial in the grower shed in a future project.
... The use of Electrolyzed Water (EW) is a promising strategy in the egg washing process. EW is generated by electrolysis of NaCl in water (Cheng et al., 2012) and its use has previously been reported in cutting boards (Venkitanarayanan et al., 1999) spinach (Guentzel et al., 2008), lettuce (Abadias et al., 2008;Koseki et al., 2004), meat (Fabrizio and Cutter, 2004), and strawberries (Udompijitkul et al., 2007) for the control of foodborne diseases. Its bactericidal effects are explained by three characteristics: Oxidation Reduction Potential (ORP), presence of reactive chlorine and oxygen species like hypochlorous acid (HOCl), and pH. ...
Article
Neutral Electrolyzed Water (NEW) was tested in vitro and on artificially contaminated eggs against Salmonella enterica subsp. enterica or Escherichia coli. The antibacterial effect was measured 30 s after treatment. NEW microbicide activity results were compared against 2% citric acid and 0.9% saline solutions. NEW caused an in vitro decrease in Salmonella titers by ˃5.56 Log10 CFU mL-1 and in artificially contaminated eggs by ˃1.45 Log10 CFU/egg. When it was tested against E. coli, it decreased in vitro bacterial titers by ˃3.28 Log10 CFU mL-1 and on artificially contaminated eggs by ˃6.39 Log10 CFU/egg. The 2% citric acid solution caused an in vitro decrease of 0.4 Log10 CFU mL-1 of Salmonella and E. coli and on eggs artificially contaminated with E. coli or Salmonella there was a decrease of 0.06 and 0.62 Log10 CFU/egg respectively. We evaluated egg cuticle integrity by scanning electron microscopy after treatments with evaluated solutions; the 2% citric acid solution caused damage to the cuticle and exposed eggshell pores and no interaction of NEW or NaCl with the cuticle was observed. NEW treatment showed a fast-bactericidal effect in vitro and table eggs.
... Similarly, spray application of sodium hypochlorite solution with 200 ppm FAC reduced L. monocytogenes inoculated on whole Red Delicious apples by ~0.9 log 10 CFU/cm 2 after a contact time of 1 min (Beuchat et al., 1998). A 1-min exposure to NEW at 89 ppm FAC reduced L. innocua, a non-pathogenic species closely related to L. monocytogenes, in lettuce by ~1.2 log 10 CFU/g (Abadias et al., 2008). Increasing JC9450 concentration to 0.50% enhanced its antimicrobial efficacy, possibly due to the increased production of bactericidal ROS. ...
Article
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Recent multistate outbreaks and recalls of fresh apples due to Listeria monocytogenes contamination have increased consumer concerns regarding fresh and processed apple safety. This study aimed to evaluate the antimicrobial efficacy of two sanitizers, mineral oxychloride (JC9450) and neutral electrolyzed water (NEW), for inactivation of L. monocytogenes on fresh apples. A 2-min treatment of 0.125% (v/v) JC9450 with 100 ppm free available chlorine (FAC) or NEW with 110 ppm FAC caused 0.9–1.2 log10 CFU/apple reduction of L. monocytogenes on both Granny Smith and Fuji apples 24 h post-inoculation. Increasing JC9450 concentration to 0.25 and 0.50% significantly improved its bactericidal effect and reduced L. monocytogenes on Granny Smith apples by ~2.0 and 3.8 log10 CFU/apple, respectively, after a contact time of 2 min. At a shorter contact time of 30 sec, the inactivation efficacy of chlorine and 0.25–0.50% JC9450 against L. monocytogenes on apples was significantly reduced compared with the respective 2-min wash. Furthermore, no L. monocytogenes was recovered in deionized water prepared antimicrobial wash solution or on non-inoculated apples post-NEW with 110 ppm FAC or 0.125–0.5% JC9450 washes, indicating their ability to prevent cross-contamination. In addition, a 2-min exposure to NEW with 110 ppm FAC and 0.50% JC9450 reduced apple native microbiota including total plate count by 0.14 and 0.65 log10 CFU/apple, respectively, and yeast and mold counts by 0.55 and 1.63 log10 CFU/apple, respectively. In summary, L. monocytogenes attached on apples was difficult to eliminate. JC9450 and NEW demonstrated a dose-dependent reduction in L. monocytogenes on apples and successfully prevented cross-contamination, indicating their application potential in post-harvest washes of apples.
... The results of this study are consistent with those of Abadias et al. (2008), who compared the effect of using neutral electrolyzed water as an alternative to sodium hypochlorite, the most common disinfectant of fresh vegetables. Its bactericidal activity at a content of approximately 50 ppm free chlorine and pH 8.60 against E. coli O157: H7, salmonella and others on lettuce was similar to that of the chlorinated water (120 ppm free chlorine). ...
Article
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The effect of ionized aqueous solutions (anolytes and catholytes) in the processing of fruits (cherries, morellos and strawberries) for decontamination has been tested. Freshly prepared anolytes and catholytes without the addition of salts were used, as well as stored for 7 months anolytes, prepared with 0.5% NaCl and a combination of 0.5% NaCl and 0.5% Na2CO3. The anolyte prepared with a combination of 0.5% NaCl and 0.5% Na2CO3, as well as the anolyte obtained with 0.5% NaCl, exhibit high antimicrobial activity against the surface microflora of strawberries, cherries and sour cherries. They inactivate E. coli for 15 minutes. The other species of fam. Enterobacteriaceae were also affected to the maximum extent, as is the total number of microorganisms, especially in cherries and sour cherries. Even stored for 7 months, they largely retain their antimicrobial properties.Anolyte and catholyte, obtained without the addition of salts, showed a lower effect on the total number of microorganisms, but had a significant effect on Gram-negative bacteria, and especially with regard to the sanitary indicative E. coli.
... Recently, scientists are investigating the potential of electrolysed water (EW) as a disinfectant to improve food safety because conventional methods has lower acceptability due to consumer perception. EW is considered environmental friendly sanitizer because it is generated from dilute salt and water, cause less corrosion to surface of production plant and eliminate the effect to human body [7,8]. ...
Conference Paper
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Uncontrolled growth of microorganism in foodstuff pose a severe challenge to the food industry, as it could leads to food spoilage, or even foodborne disease if the microorganism is pathogenic. To deal with these threats, sanitizers has been widely applied widely by food industry. In the last two decades, electrolyzed water (EW) has been food to be a promising new sanitizer for food industry, as it is more environmentally friendly compared to conventional chlorine-based disinfectants. This paper reviews the recent progress on the application of EW as a food sanitizer. EW was produced by the electrolysis of diluted NaCl (or HCl) solution and could be classified into several subgroups (acid EW, slightly EW, neutral EW, alkaline EW, low concentration) based on their pH and available chlorine concentration. The efficacy of using EW to inhibit the growth of several most important microorganism of food safety concern were proven by numerous studies. Besides, the application of EW has been seldomly associated with detrimental effects on the nutritional and sensory proprieties of food. However, its antimicrobial potency was affected by factors such as pH, temperature, storage time, and organic matter.
... most promising as it contains predominantly HOCl, which is more effective than ClO − for microbial cell wall penetration and oxidative attack 12,17 . However, there are limited published applications of neutral EOW use in the irrigation and washing of fresh vegetables 18,19 or fruit 20,21 , with publications to date mainly focussing on its use in the seafood 22 and meat 17,23,24 industries. The use of Na-based salts rather than K for generation of the EOW might be of concern in the context of vegetable production, because of the potential problems associated with Na accumulation in soil, in contrast to the potential benefit of K supplementation for crop growth. ...
Article
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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.
... A volume of 4.5 ml of PAD or sterile 0.85% saline solution was transferred into sterile 50 ml tubes containing 0.5 ml of each bacterial suspension. The volume ratio of PAD and bacterial suspension in this study was consistent with other research using plasma treated water or electrolyzed water [27,28]. The obtained bacterial suspensions were mixed thoroughly for 5 s and incubated at room temperature for different time intervals (1, 2, 3, 4, and 5 min). ...
... The oxidation-reduction potential (ORP) High (more than 1000) contains free chlorine ions, on the other electrode the cathode produces Catholyte It has a pH of 10.0-11.5 and dissolved hydrogen with redox potential (ORP) Very low (-800 to -900mV). The biggest advantage of using electrolyzed water is to stop the activity of pathogens and it has less impact on the environment and users due to the absence of chemicals [6] and the use of neutralized electrolytic water (ANK) in the water given to poultry, it is considered a new method of treatment because of its beneficial effect on the health status [7; 8]. ...
... electrical conductivity-1160 mV, available Cl-50 mg/L) for 15 s could limit the proliferation of Listeria monocytogenes, Salmonella typhimurium, and E. coli. The population capacity was 1.23, 1.67, and 1.81 log on the stainless-steel surface, and it was deduced that a longer contact time could increase the disinfection effect [66,90]. It was reported that in order to sterilize bovine hides before slaughter, electrically oxidized water constituting 70.0 mg/L of available Cl was sprayed sequentially at a temperature of 60 • C. Sprays can reduce the amount of anaerobic bacteria by 3.5 logs CFU/100 cm 2 and the number of Enterobacter by 4.3 log CFU/100 cm 2 . ...
Article
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Electrolyzed water is a novel disinfectant and cleaner that has been widely utilized in the food sector for several years to ensure that surfaces are sterilized, and that food is safe. It is produced by the electrolysis of a dilute salt solution, and the reaction products include sodium hydroxide (NaOH) and hypochlorous acid. In comparison to conventional cleaning agents, electrolyzed water is economical and eco-friendly, easy to use, and strongly effective. Electrolyzed water is also used in its acidic form, but it is non-corrosive to the human epithelium and other organic matter. The electrolyzed water can be utilized in a diverse range of foods; thus, it is an appropriate choice for synergistic microbial control in the food industry to ensure food safety and quality without damaging the organoleptic parameters of the food. The present review article highlights the latest information on the factors responsible for food spoilage and the antimicrobial potential of electrolyzed water in fresh or processed plant and animal products.
... Chlorine dioxide molecules can spread very well including building cavities, and therefore can have an extremely thorough disinfection performance (Buttner et al. 2004;Lowe et al. 2013). Previous studies showed that weak acid hypochlorous water (WAHW) also has a good disinfection performance (Abadias et al. 2008;Koide et al. 2009;Rahman et al. 2010;Ono et al. 2012). WAHW is generated from water and dilute salt solution and its final product is water after use (Hricova et al. 2008;Møretrø et al. 2012). ...
Article
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The disinfection efficiencies of two chemical disinfectants, chlorine dioxide and weak acid hypochlorous water (WAHW), were examined in the soiled room and dishwashing room of a hospital infectious disease ward in Taiwan. The investigations were conducted in two seasons, namely winter and summer, in order to examine the correlation between the bioaerosol concentration and the environmental factors. In addition, a single-daily disinfection mode (SM) and a twice-daily disinfection mode (TM) were applied in this study. The results showed that the bacteria and fungi colony counts were strongly correlated with the temperature. Both disinfectants reduced the bacteria and fungi concentrations in the considered rooms. However, of the two disinfectants, the ClO2 showed a stronger disinfection effect than the WAHW. It means that when using ClO2 as the disinfectant, the disinfection efficiency of the TM treatment mode is significantly better than that of the SM treatment mode. But, when using WAHW as the disinfectant, no significant difference is found between the disinfection efficiencies of the two methods. Overall, the results showed that the application of ClO2 twice daily provided the most effective means of satisfying the Taiwan EPA guidelines for the indoor air quality of hospital medical wards.
... In case of the bacteria, the cell membranes of Escherichia coli and Staphylococcus aureus could be damaged when treated by electrolyzed water, but it could not make their DNA and RNA degraded. According to findings developed by Abadias et al. (2008), the bactericidal activity of 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. Seo et al. (2018), evaluating the decontamination of Brassica oleracea var. ...
Article
The consumption of fresh-cut fruit is attributed to the health and convenience benefits of consumers. However, reports about associated-microorganism diseases have aroused the consumer's interest. Chlorine-based compounds are the classic method for the microbiological control. These compounds have been used to sanitize fruits and vegetables in the minimal processing industry worldwide, but they react with the organic matter present in the water that leads to the formation of potentially cancerous chlorinated compounds. Aiming to develop alternative technology to sodium hypochlorite, this study evaluated treatment with neutral electrolyzed water (NEW) on microbiology, quality and sensory parameters of fresh-cut mangoes. ‘Tommy Atkins’ mangoes were processed into cubes and treated by immersion in NEW solutions (0, 75, 150, 225 and 300 mg L⁻¹) or chlorine-based product at 200 mg L⁻¹, and then, stored at 3 ± 2 °C, 85 ± 5% RH for 0, 6 or 12 days. The microbiota of fresh-cut mangoes was reduced by NEW treatments similarly as observed by sanitization with commercial product. Nutritional components as vitamin C, carotenoids and phenolics were preserved by NEW treatments or commercial chlorine. Concerning the sensory aspects, the NEW at150 mg L⁻¹ presented the same good acceptability as observed for commercial chlorine and even lower off-flavor intensity than this chlorine-based sanitizer. Fresh-cut mangoes treated with NEW at different concentrations showed equivalent microbiological and quality parameters to the mango treated with commercial sanitizer, which allow to provide that electrolyzed water is a viable alternative to chlorine-based compounds as a disinfectant, considering the lower adverse impact on the environment and possibly on human health.
... They allow the consumer to procure only the quantities of fresh produce required. While fresh-cut produce requires relatively little product transformation, it requires investment in technology, equipment, management systems and strict observance of food safety principles and practices to ensure product quality 17,18,19 . ...
Article
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Raw salad vegetables are evaluated for the consumer’s perceptions on taking ready to eat fresh cut-vegetables and the effectiveness of some non-chlorine disinfectants [peracetic acid (PAA), shell powder (SP) and hydrogen peroxide (H2O2)] in improving the microbial safety, quality and shelf life of ready to eat fresh-cut vegetables (lettuce, carrot and cucumber) at ambient and refrigeration temperature. Consumer’s perception study results identified three clusters of consumers, whose preferences are related to purchasing styles and socio-demographic variables.The overall positive attitude of consumers was evident towards convenience, taste and appearance, but safety and health benefit attributes get importance while buying the ready to eat fresh-cut vegetables.The microbiological and visual observation result demonstrated that, all the non-chlorine sanitizers used were able to decrease the bacterial population in fresh-cut vegetables initially; however, microbial population increases or remain constant or decrease depending on the types of vegetables, storage temperature and duration. In addition, among the wash-sanitizers, PAA and H2O2 showed better microbial reduction for fresh-cut lettuce, and cucumber, and SP showed better microbial reduction for fresh-cut carrot. Irrespective of sanitizer treatment refrigerated storage showed better visual quality, microbial safety and shelf life of fresh-cut produce. Therefore, this study results suggested that washing fresh-cut vegetables with produce specific sanitizer and stored at refrigerated temperature keep the quality of fresh-cut produce better compared to ambient storage. Bangladesh J Microbiol, Volume 38, Number 2, December 2021, pp 51-62
... However, Stopforth et al. studied AEW (ACC 50 ppm) in leafy greens and revealed no significant difference in the antibacterial effect above 1 min. Some other authors studied the effectiveness of EW for longer exposure times and reported similar or even lower bacterial reductions [55,56]. The reason may be that the dissociation of free chlorine or interference such as organic matter over a relatively short time [57]. ...
Article
Full-text available
Electrolyzed water (EW) has been proposed as a novel promising sanitizer and cleaner in recent years. It is an effective antimicrobial and antibiofilm agent that has several advantages of being on the spot, environmentally friendly, cheap, and safe for human beings. Therefore, EW has been applied widely in various fields, including agriculture, food sanitation, livestock management, medical disinfection, clinical, and other fields using antibacterial technology. Currently, EW has potential significance for high-risk settings in hospitals and other clinical facilities. The research focus has been shifted toward the application of slightly acidic EW as more effective with some supplemental chemical and physical treatment methods such as ultraviolet radiations and ultrasound. This review article summarizes the possible mechanism of action and highlights the latest research studies in antimicrobial applications.
... The various types of EOW described in literature include acidic EOW (pH 2-3.5), slightly acidic EOW (pH 5-6.5), alkaline EOW (pH 10-13), slightly alkaline EOW (pH 8-10), and neutral EOW (pH 7-8) (Rahman et al., 2016). Neutral EOW is used as a disinfectant in soaking and washing fresh vegetables (Abadias et al., 2008) or fruit (Torlak, 2014) and in the seafood (Khazandi et al., 2017) and meat industries (Han et al., 2018;Veasey and Muriana, 2016). It can also be used to mist greenhouses, sterilise equipment and soil, and as an additive to irrigation water. ...
Article
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The aim of the study was to analyse the effects of pH-neutral electrolysed oxidising water (pH-neutral EOW), prepared by using the Envirolyte® system, on the growth and development of chrysanthemums. The experiment included two varieties of potted ('Tonka Blanc', 'Jahou CoCo') and two cut flower varieties of chrysanthemums ('Annecy White', 'Ninja'). The test plants planted in pots were irrigated with three different solutions of pH-neutral EOW (0%, 0.1% and 0.2%). Based on the results of the study, we can confirm that pH-neutral EOW has a significant effect on the growth and development of the studied chrysanthemum varieties. In potted chrysanthemums, we found a significant effect on the increased number and diameter of inflorescences, as well as fresh and dried weight of the plant and inflorescences. Chrysanthemums for cut flowers were taller and more developed, with a greater weight of the aboveground part of the plant. Its effect on the growth and development of the studied varieties depended on the solution of the mixture. Best results were observed with the 0.2% solution of pH-neutral EOW.
... Due to its different mechanisms of action, EOW has a wide range of activity. Electrolyzed water has been evaluated for several food safety industrial applications, including use as a fresh produce wash [97,98], cleaning and decontamination of dairy facilities [99], plant production [100], pig and poultry production and food facilities [101]. Cold fogging with electrolyzed water has been effective in decontamination of rooms mainly in health care environments [102]. ...
Article
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Air is recognized as an important source of microbial contamination in food production facilities and has the potential to contaminate the food product causing food safety and spoilage issues for the food industry. Potential for aerial microbial contamination of food can be a particular issue during storage in cold rooms when the food is not packaged and is exposed to contaminated air over a prolonged period. Thus, there are potential benefits for the food industry for an aerial decontamination in cold storage facilities. In this paper, aerial decontamination approaches are reviewed and challenges encountered for their applications are discussed. It is considered that current systems may not be completely effective and environmentally friendly, therefore, it is of great significance to consider the development of nonresidual and verified decontamination technologies for the food industry and, in particular, for the cold storage rooms.
... Thus, only half the volume of the sodium chloride solution (the stock solution) is obtained as a sterilizing solution. An aqueous solution (neutral electrolyzed water, or NEW) obtained by mixing the aforementioned acidic electrolyzed water in the anode chamber and alkaline water in the cathode chamber also has potent sterilizing action [15][16][17]. However, this is a mixture of 2 solutions, so it is unlikely to stabilize as the chemical reaction proceeds. ...
Article
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Slightly acidic electrolyzed water (SAEW) was developed by Japanese companies over 20 years ago. SAEW has the advantage of potent sterilizing action while being relatively safe. This study evaluated the potential application of SAEW in spatial disinfection. Prior to experiments involving spatial spraying, the ability of SAEW to remove seven type of microorganisms that cause food poisoning was studied in vitro. Results indicated that free chlorine in SAEW, even at a low concentration (30 mg/L), was able to remove Cladosporium cladosporioides, a typical airborne fungus that degrades food, and spores such as Bacillus subtilis, a hardy bacterium. In an experiment involving spatial spraying, 3.43 log10 CFU/100 L of Staphylococcus epidermidis was sprayed in a room-sized space; the same space was then sprayed with SAEW. The number of settling microbes was measured and the sterilizing ability of SAEW was assessed. Results indicated that the concentration of S. epidermidis in the space was completely removed after 20 minutes of SAEW spraying. The above findings indicate that SAEW may be used to remove airborne microorganisms via spatial spraying.
... Hypochlorous acid is the most active of the chlorine compounds and has high bactericidal activity (36). In several studies, the efficacy of NEW has been evaluated for reduction of bacterial population in fresh meat (12,35,42,43), eggshells (44), seafoods (28), and vegetables (1). If NEW were to be combined with other chemical disinfectants such as organic acids, its antimicrobial efficacy might increase. ...
Article
This study was conducted to evaluate the antimicrobial efficacy of near-neutral electrolyzed water (NEW) and peroxyacetic acid (PAA) alone and in combination for reducing the foodborne pathogens Salmonella Typhimurium, Escherichia coli, and Listeria monocytogenes in pure culture and fresh chicken meat. The NEW treatments resulted in 100% inactivation of these organisms in pure culture at concentrations of 50, 100, and 200 μg/mL and 2 min of contact time at room temperature. The PAA treatments at concentrations of 100 and 200 μg/mL resulted in 100% inactivation of the tested pathogens. The combination of NEW and PAA had a greater bactericidal effect than did each individual treatment. The inoculated chicken meat samples were dipped for 10 min in each treatment solutions (100 and 200 μg/mL NEW, 200 and 400 μg/mL PAA, 100 μg/mL NEW + 200 μg/mL PAA) at room temperature. Samples dipped in water were used as a control. The greatest reduction was achieved with the combined treatment, which significantly (P < 0.05) reduced total cells and healthy cells of Salmonella Typhimurium, E. coli, and L. monocytogenes by 2.79 and 3.01, 2.63 and 2.75, and 1.47 and 1.99 log CFU/g, respectively. The findings of this study indicate that a combined treatment with NEW and PAA has potential as a novel antimicrobial agent to improve the microbial safety of fresh chicken meat. © 2021, International Association for Food Protection. All rights reserved.
... For example, Junker et al. (2021) identified two wheat ATIs as strong activators of innate immune responses in monocytes, macrophages, and dendritic cells. While not specific to FD, this finding suggests that ATIs may fuel inflammation and immune reactions in intestinal immune disorders [63]. ...
Article
Full-text available
Functional dyspepsia (FD) is a common disorder of gut-brain interaction, characterised by upper gastrointestinal symptom profiles that differentiate FD from the irritable bowel syndrome (IBS), although the two conditions often co-exist. Despite food and eating being implicated in FD symptom induction, evidence-based guidance for dietetic management of FD is limited. The aim of this narrative review is to collate the possible mechanisms for eating-induced and food-related symptoms of FD for stratification of dietetic management. Specific carbohydrates, proteins and fats, or foods high in these macronutrients have all been reported as influencing FD symptom induction, with removal of ‘trigger’ foods or nutrients shown to alleviate symptoms. Food additives and natural food chemicals have also been implicated, but there is a lack of convincing evidence. Emerging evidence suggests the gastrointestinal microbiota is the primary interface between food and symptom induction in FD, and is therefore a research direction that warrants substantial attention. Objective markers of FD, along with more sensitive and specific dietary assessment tools will contribute to progressing towards evidence-based dietetic management of FD.
... Among all these types, acidic EOW has got the most attention due to its highly efficient antimicrobial activity principle. Alkali EOW and [18] Neutral electrolyzed water Neutral electrolyzed water NEW 7-8 750 50 [14], [88], [67,40] NEW are also being researched for their efficacy in different antimicrobial applications, and other uses such as cleaning. Both acidic and alkali EOW are generated in an electrolysis chamber where the anode and cathode are separated with the help of a diaphragm. ...
Article
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Electrolyzed oxidizing water (EOW) is one of the promising novel antimicrobial agents that have recently been proposed as the alternative to conventional decontamination methods such as heat and chemical sanitizers. Acidic EOW with pH ranging from 2 to 5 is regarded most applicable in the antimicrobial treatment of vegetables and meats. Neutral and alkaline electrolyzed water have also been explored in few studies for their applications in the food industry. Neutral electrolyzed water is proposed to solve the problems related to the storage and corrosion effect of acidic EOW. Recently, the research focus has been shifted toward the application of slightly acidic EOW as more effective with some supplemental physical and chemical treatment methods such as ultrasound and UV radiations. The different applications of electrolyzed water range from drinking water and wastewater to food, utensil, and hard surfaces. The recent studies also conclude that electrolyzed water is more effective in suspensions as compared with the food surfaces where longer retention times are required. The commercialization of EOW instruments is not adopted frequently in many countries due to the potential corrosion problems associated with acidic electrolyzed water. This review article summarizes the EOW types and possible mechanism of action as well as highlights the most recent research studies in the field of antimicrobial applications and cleaning. Electrolyzed water can replace conventional chemical decontamination methods in the industry and household. However, more research is needed to know its actual mechanism of antimicrobial action along with the primary concerns related to EOW in the processing of different food products.
... Fresh and minimally processed fresh-cut products are naturally contaminated by microorganisms of several sources, including the farm environment, post-harvest handling and processing (Abadias et al., 2008). The microflora associated with raw fruits mostly includes yeasts and moulds (Burnett and Beuchat, 2000;Tournas, 2005). ...
Article
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Mango has a short shelf-life after harvesting. The use of edible coatings on the elaboration of minimally processed mango is an alternative for its commercialization. In the present work edible coatings based on chitosan, starch-salicylic acid and starch-cinnamaldehyde-thymol were applied to fresh cut-mango. Weight loss, soluble solids, titratable acidity, color and microbiological analyses were studied along storage for 12 days at 8 °C and 90% relative humidity. Titratable acidity was the highest for mangoes coated with chitosan and the lowest was for starch-salicylic acid coating. Regarding instrumental texture, fruit coated with chitosan showed a higher penetration force compared to fruit coated with starch and uncoated samples. Microbiological results showed that all coated mangoes inhibited growing of fungi and yeast whereas uncoated samples showed an increase of both microorganisms along 12 days of storage period.
... Due to its different mechanisms of action, EOW has a wide range of activity. Electrolyzed water has been evaluated for several food safety industrial applications, including use as a fresh produce wash [97,98], cleaning and decontamination of dairy facilities [99], plant production [100], pig and poultry production and food facilities [101]. Cold fogging with electrolyzed water has been effective in decontamination of rooms mainly in health care environments [102]. ...
Article
Fresh fruits and vegetables carry a heavy load of microorganisms which may cause the risks of food‐borne illness to the consumer. Even after washing with water, there is a need for sanitization and disinfection to drop down a load of harmful microbes under the safe limit. Sanitizers and disinfectants are not only cost‐effective but also non‐hazardous and eco‐friendly. Moreover, they should not hamper the organoleptic and nutritional properties of fresh produce. With rising demand for safe, nutritious, and fresh fruits and vegetables, many new disinfectants and treatments are commercially available. During this COVID‐19 outbreak, knowledge of sanitizers and disinfectants for fresh fruits and vegetables is very important. This review focuses on working principles, applications, and related legislation of physical and chemical disinfection technologies (chlorine, chlorine dioxide, ozone, organic acids, electrolyzed water, irradiation, ultrasound etc.) and their effectiveness for shelf‐life extension of fresh produce.
Article
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Background/purpose: Electrolyzed water has been identified as an effective disinfectant that could represent as an alternative to sodium hypochlorite. Unfortunately, it remains unclear whether the texture or physical properties of dentin are affected by the application of electrolyzed water of different acidities. This study was aimed to assess the influence of electrolyzed waters with differing pHs on the demineralizing of inner dentin. Materials and methods: The coronal superficial dentin of 20 human molars was exposed and further bisected into two pieces perpendicular to the dentin surface. The samples were immersed in strongly acidic electrolyzed water (AW group), neutral electrolyzed water (NW group), 5% sodium hypochlorite (positive control, NL group), or deionized water (negative control, DW group). Microhardness of the inner layer dentin was measured at a depth of 25 and 50 μm beneath the superficial surface layer every 5 up to 60 min. Results: At a depth of 25 μm, microhardness decreased with increasing immersion time in all but the DW group. The AW group exhibited a decreasing trend from the first 5 min that became significant after 35 min of immersion and was the most rapid decrease in the four groups. The rate of decline in the NW group was low and similar to that of the NL group. Both NW and NL groups exhibited significantly less demineralization than the AW group after 15 min of immersion. No significant microhardness change was found at a depth of 50 μm in any of the samples. Conclusion: AW produces a more pronounced softening of dentin than NW at a depth of 25 μm.
Article
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During the processing of poultry, disinfectants are commonly added to cooling water tanks called “chillers” to reduce microorganism populations that can affect food quality. The present study, evaluated the effectiveness of neutral electrolyzed water in a pilot-project-sized chiller for the elimination of pathogenic microorganisms in gizzards and necks chicken. The microbiological analysis of the samples was processed and analyzed in three different food microbiological analysis laboratories. The results demonstrated a maximum microbial load reduction of 1.97686 log CFU/g for Escherichia coli and 1.76313 log CFU/g for Staphylococcus aureus in all samples processed with neutral electrolyzed water. Sodium hypochlorite, a disinfectant in common industrial use, did not achieve significant reductions in microbial loads below those of untreated necks and gizzards for either of the microorganisms in question. Based on these results, this study thus proposes the use electrolyzed water as an alternative disinfectant to sodium hypochlorite for use in chillers; being a sustainable solution that differs from conventional disinfectants in its lack of human or environmental side effects.
Article
L. monocytogenes has been linked to fresh produce and detected in the retail environment. This study simulated the retail practices (crisping, misting, and storage) of unbagged whole heads of romaine lettuce to determine the growth of L. monocytogenes and natural psychrotrophic microflora. Three nalidixic acid-resistant strains of L. monocytogenes strains were inoculated to each head of lettuce (≈5 log 10 CFU/g). For crisping, 24 heads of romaine lettuce were immersed in tap water or electrolyzed water (EW; free chlorine: 55 ppm) for 5 min, followed by holding at 5 ○ C for 2 h. The water-crisped (WC), EW crisped (EWC), or non-crisped (NC) lettuces were placed in a commercial refrigerated cabinet for misting at 5 ○ C. After 24-h misting, heads of lettuce were placed in perforated drain boxes with cover at 5 ○ C or 15 ○ C. The tap water and EW crisping achieved 1.3 and 2.9 log 10 CFU/g reduction of L. monocytogenes, respectively. Approximately 1 log additional reduction of L. monocytogenes in the non-crisped lettuce was shown after misting ( p < 0.05), but no significant effect of misting on the population of L. monocytogenes was observed on WC or EWC lettuces ( p > 0.05). Regardless of the storage temperature or misting, L. monocytogenes populations remained significantly ( p < 0.05) lower on EWC lettuce than NC and WC lettuce. On days 4 and 7 of storage, the natural psychrotrophic bacteria on lettuce stored at 5°C was significantly lower than stored at 15°C, and its population was not affected by crisping and misting. These provide insight into the influence of retail lettuce handling practices on the risk of L. monocytogenes.
Article
Outbreaks involving romaine and iceberg lettuce are frequently reported in the United States. Novel technologies are needed to inactivate pathogens without compromising product quality and shelf life. In this study, the effects of a process aid composed of silver dihydrogen citrate, glycerin, and lactic acid (SGL) on Escherichia coli and Listeria monocytogenes concentrations on lettuce immediately after washing and during cold storage were evaluated. Sensory and quality attributes of fresh-cut iceberg lettuce were also evaluated. Laboratory results indicated that application of SGL solution for 30 second as a first step in the washing process resulted in a 3.15 log reduction in E. coli O157:H7 immediately after washing. For E. coli O157:H7 a significant difference between SGL treatment and all other treatments was maintained until day 7. On day zero, SGL led to a 2.94 log reduction of L. monocytogenes. However, there was no significant difference between treatments with or without SGL regardless of storage time. Pilot-plant results showed that samples receiving SGL spray followed by chlorinated flume wash exhibited a greater reduction (1.48 log) in nonpathogenic E. coli populations at the end of shelf life than other treatments (p<0.05). Additional pilot plant tests were conducted to investigate the hypothesis that SGL residues could continue to impact microbial survival on the final washed lettuce. Results show that pathogens introduced subsequent to flume washing of lettuce pretreated with SGL solution were not affected by antimicrobial residues. The final quality and shelf life of flume washed lettuce were also unaffected by pretreatment with SGL. In conclusion, the results of this study demonstrate that this new technology has the potential to accelerate E. coli die-off on fresh-cut lettuce during cold storage and improve product safety, while not affecting quality throughout the shelf life of the finished products.
Chapter
Food safety is a burning issue in the present world. Safe sanitizers are obligatory for maintaining quality of food and increasing the shelf life of fresh produce and other agricultural products. Food industries have been using electrolyzed water (EW) as a unique sanitizer for the past two decades which has excellent results to reduce the microbial count. Hurdle technology, e.g., combination of EW with ultrasonication, short-term heat treatment, organic acids, and salts, found to have more effective results in reducing microorganisms which overcame the little shortcomings with EW like corrosiveness and maintained organoleptic qualities. In this chapter, we are going to discuss the production of EW and its combination with ultrasonication, short-term heat treatment, organic acids, and salts to produce a novel sanitizer.
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The growth of a yeast mixture, Candida sake, Hanseniaspora uvarum, Pichia fermentans, Metschnikowia pulcherrima, on fresh-cut apple (Royal gala), at 4 °C, was studied, as well as the reduction of yeasts using Ultraviolet-C (UV-C), acidic (AEW) and neutral (NEW) electrolyzed waters, and sodium hypochlorite (SH). Apple portions were contaminated then disinfected with UV-C (2.5-10kJ/m²), AEW, NEW and SH (100ppm). During 9 days at 4 °C, yeasts growth rate was 0.34 day⁻¹ and the stationary phase occurred after 6 days (7.42 LogCFU/g). The initial microbial reduction and the half-life time values, using the inverse hyperbola model, ranged from 1.72 to 1.81 LogCFU/g and 6.52 to 11.70 day (UV-C), or 0.91 to 1.96 LogCFU/g and 0.68 to 4.38 day (chemical treatments), where SH was the least efficient (0.92 LogCFU/g and 2.96 day). The most effective treatment was UV-C (7.5 and 10kJ/m²). The yeasts psychrotrophic profile highlights the importance of avoiding contamination/cross-contaminations in all processing.
Article
This study evaluated the virucidal efficacy of acidic electrolyzed water (AEW) against African swine fever virus (ASFV) and avian influenza virus (AIV), according to the Animal and Plant Quarantine Agency (APQA) guidelines for efficacy testing of veterinary disinfectants. AEW (pH 5.0–6.5) was prepared using a commercially available “Electrolyzed Water Generator” with a free chlorine concentration (FCC) of 5–140 ppm, and its efficiency in reducing the titer of ASFV and AIV was tested in a suspension under low- and high-level organic soiling. Under low-level organic soiling conditions, AEW with FCC ≥40 ppm was effective against ASFV; under high-level organic soiling conditions, AEW with FCC ≥80 ppm was effective against ASFV. Under low-level organic soiling conditions, AEW with FCC ≥60 ppm was effective against AIV; under high-level organic soiling conditions, AEW with FCC ≥100 ppm was effective against AIV. The virucidal effect of AEW seemed dependent on the FCC and the presence of organic soiling. Based on these data, we recommend the following minimum FCCs in AEW treatment for routine disinfection in veterinary field under low- and high-level organic soiling conditions: for ASFV, 50 ppm and 100 ppm; and for AIV, 75 ppm and 125 ppm, respectively. In conclusion, the virucidal effects of AEW against ASFV and AIV emphasize its potential utility as a disinfectant, and we suggest considering organic soiling conditions while using AEW for implementing effective control measures for field applications.
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La industria de alimentos vegetales consume grandes volúmenes de agua de buena calidad y genera grandes cantida­des de agua residual. Uno de los sistemas que se pueden aplicar para reducir el consumo y el vertido de agua es la reutilización del agua de lavado. Para llevar a cabo la reutilización del agua sin comprometer la seguridad microbiológica y química de los alimentos es necesario optimizar el uso de agentes antimicrobia­nos. El cloro ha sido tradicionalmente el tratamiento de desinfec­ción usado por la industria hortofrutícola para el agua de lavado. Sin embargo, su uso tiene la desventaja de la acumulación de subproductos de desinfección, lo que ha impulsado el estudio y el uso de desinfectantes alternativos como el ácido peroxiacéti­co. En cualquier caso, el mantenimiento de la seguridad micro­biológica y química de los alimentos vegetales frescos, en lo que respecta a la etapa de lavado, pasa por la selección de los límites operacionales que deben mantenerse en cuanto a la concentra­ción de desinfectante, así como la monitorización y control de los parámetros críticos relacionados con la desinfección, como es el contenido en materia orgánica. La optimización de la desinfec­ción tiene que tener en cuenta las peculiaridades de cada caso, incluyendo el tipo de producto lavado, el desinfectante usado, y el diseño y manejo de la línea de lavado.
Article
Fresh produce shall be thoroughly washed at the retail level prior to serving to the consumer with potable water. Foodborne pathogens if present on a product may transfer to the wash water and cross-contaminate other products immersed in the water. Typically, an entire carton of lettuce (24 heads) is washed together increasing the likelihood of cross-contamination due to the close contact between each head. This study aimed to compare the effects of two wash batch volumes – “low” (8 heads) and “high” (24 heads) on the efficacy of two commercial water antimicrobials and cross-contamination. Red leaf lettuce was spot-inoculated (~5.0 log CFU/g) with Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes. In the first batch of washing, inoculated lettuce was washed with non-inoculated lettuce, followed by reuse of the water/antimicrobials twice washing only non-inoculated lettuce. Samples of inoculated and non-inoculated lettuce were collected to determine aerobic plate count (APC) as well as the populations of STEC and L. monocytogenes. Microbiological analysis of the wash water was also conducted. Wash volume (8 versus 24 lettuce heads) had limited effects on the antimicrobial activities of the inventions evaluated. Instead, high-volume wash increased the rate of cross-contamination between non-inoculated and inoculated lettuce, and cross-contamination of non-inoculated lettuce through wash water reuse. Retailers should consider volume of product processed per batch, reuse of wash water, and use of an appropriate water antimicrobial in consideration of mitigating potential product cross-contamination.
Article
Currently, electrolyzed water, a sustainable and environmentally friendly disinfectant produced through electrolysis of an acid or salt, has become very popular because of its applications in various sectors such as health, agriculture, and food. Influencing factors are important for optimizing the electrolyzed water production process and maximizing application efficiency. Factors that influence the production and efficiency of electrolyzed water, including water and electrolyte properties, electrode material, current, storage, and application factors, were reviewed in this study. Moreover, some commercially available generator models, their specifications, and issues are discussed along with future recommendations. This work summarizes the available literature from January 2000 to December 2020, reporting studies that can assist in understanding various parameters affecting the production and stability of electrolyzed water. This can provide further insights and aid researchers in optimizing the process and address the issues faced by the existing systems by offering new perspectives in future studies.
Chapter
Fresh fruits and vegetables are susceptible to attack by spoilage and pathogenic microorganisms if not handled correctly during or after harvest. Postharvest disinfection of commodities is a curative operation to inhibit fungal pathogens and human bacterial pathogens and therefore enhance food safety. Deterioration of fruits and vegetables can only be prevented by adopting the inhibition of postharvest pathogens and thus ensuring prolonged storage life. This chapter comprises factual, chemical, and administrative context on some of the essential sanitizers existing for the practice nowadays. These include chlorine, chlorine dioxide, ozone, ethanol, hydrogen peroxide, organic acids, and electrolyzed water. A broad description about postharvest application, disinfection mechanism, and regulatory guidelines of these sanitizers has been given in this chapter. This chapter concludes that disinfectant is a vital tool to reduce postharvest decay in fruits and vegetables. In some conditions, sanitization is a pretreatment to the productive employment of postharvest methodology. This chapter clears the controversial, unjustified, and bad reputation of the use of chemical disinfectants as they leave no or much lesser amounts of remnants of the nonhazardous level. The world may consider the use of chemical disinfectants in an eco-friendly way.
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Sanitizers are commonly used in post-harvest interventions to reduce potential foodborne pathogen contamination of fresh produce. An appropriate non-pathogenic surrogate of Listeria monocytogenes is needed to verify the laboratory obtained antimicrobial intervention results in commercial facilities. The objective of this study was to identify a surrogate of L. monocytogenes to validate the sanitation efficiency of fresh apples. We evaluated and compared the behavior of Listeria innocua, Enterococcus faecium NRRL B-2354, Pediococcus acidilactici and Lactobacillus plantarum, to that of L. monocytogenes on apples regarding attachment, survival during storage, and resistance to various antimicrobial washes. L. monocytogenes, E. faecium and L. innocua persisted on fresh apple surfaces at 6.4–6.5 Log10 CFU/apple for 48 h at room temperature, while L. plantarum and P. acidilactici slightly decreased. All the selected surrogate candidates demonstrated comparable adhesion strength with L. monocytogenes in response to three sequential water washes. E. faecium and L. innocua showed similar or higher antimicrobial resistance than L. monocytogenes to chlorine, neutral electrolyzed water, JC9450, peroxyacetic acid (PAA), and Neo-Pure, regardless of apple variety or contact time. However, L. plantarum and P. acidilactici were significantly more susceptible to PAA and Neo-Pure than L. monocytogenes. Data, collectively, identified E. faecium as a promising non-Listeria surrogate of L. monocytogenes for in-plant validation of sanitizer interventions of fresh apples or other related fresh produce.
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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.
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One milliliter of culture containing a five-strain mixture of Escherichia coli O157:H7 (approximately 10(10) CFU) was inoculated on a 100-cm2 area marked on unscarred cutting boards. Following inoculation, the boards were air-dried under a laminar flow hood for 1 h, immersed in 2 liters of electrolyzed oxidizing water or sterile deionized water at 23 degrees C or 35 degrees C for 10 or 20 min; 45 degrees C for 5 or 10 min; or 55 degrees C for 5 min. After each temperature-time combination, the surviving population of the pathogen on cutting boards and in soaking water was determined. Soaking of inoculated cutting boards in electrolyzed oxidizing water reduced E. coli O157:H7 populations by > or = 5.0 log CFU/100 cm2 on cutting boards. However, immersion of cutting boards in deionized water decreased the pathogen count only by 1.0 to 1.5 log CFU/100 cm2. Treatment of cutting boards inoculated with Listeria monocytogenes in electrolyzed oxidizing water at selected temperature-time combinations (23 degrees C for 20 min, 35 degrees C for 10 min, and 45 degrees C for 10 min) substantially reduced the populations of L. monocytogenes in comparison to the counts recovered from the boards immersed in deionized water. E. coli O157:H7 and L. monocytogenes were not detected in electrolyzed oxidizing water after soaking treatment, whereas the pathogens survived in the deionized water used for soaking the cutting boards. This study revealed that immersion of kitchen cutting boards in electrolyzed oxidizing water could be used as an effective method for inactivating foodborne pathogens on smooth, plastic cutting boards.
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Salmonella enterica serotype Baildon, a rare serotype, was recovered from 86 persons in eight states; 87% of illnesses began during a 3-week period ending January 9, 1999. Raw restaurant-prepared tomatoes were implicated in multiple case-control studies. Contamination likely occurred on the farm or during packing; more effective disinfection and prevention strategies are needed.
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The increasing availability of bagged prepared salad vegetables reflects consumer demand for fresh, healthy, convenient, and additive-free foods that are safe and nutritious. During May and June 2001 a study of retail bagged prepared ready-to-eat salad vegetables was undertaken to determine the microbiological quality of these vegetables. Examination of the salad vegetables revealed that the vast majority (3,826 of 3,852 samples; 99.3%) were of satisfactory or acceptable microbiological quality according to Public Health Laboratory Service microbiological guidelines, while 20 (0.5%) samples were of unsatisfactory microbiological quality. Unsatisfactory quality was due to Escherichia coli and Listeria spp. (not Listeria monocytogenes) levels in excess of 10(2) CFU/g. However, six (0.2%) samples were of unacceptable microbiological quality because of the presence of Salmonella (Salmonella Newport PT33 [one sample], Salmonella Umbilo [three samples], and Salmonella Durban [one sample]) or because of a L. monocytogenes level of 660 CFU/g, which indicates a health risk. In each case, the retailer involved and the UK Food Standards Agency were immediately informed, and full investigations were undertaken. Nineteen cases of Salmonella Newport PT33 infection were subsequently identified throughout England and Wales. The outbreak strain of Salmonella Newport PT33 isolated from the salad and from humans had a unique plasmid profile. Campylobacter spp. and E. coli O157 were not detected in any of the samples examined. The presence of Salmonella, as well as high levels of L. monocytogenes, is unacceptable. However, minimally processed cut and packaged salad is exposed to a range of conditions during growth, harvest, preparation, and distribution, and it is possible that these conditions may increase the potential for microbial contamination, highlighting the necessity for the implementation of good hygiene practices from farm to fork to prevent contamination and/or bacterial growth in these salad products.
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Since the beginning of 2007, the Health Protection Agency (HPA) Laboratory of Enteric Pathogens (LEP) has reported on 51 human isolates of Salmonella Senftenberg in England and Wales. This represents a significant rise compared to less than 10 in the same time period in 2006 and 2005. Of the 51 isolates, 35 (69%) have been received since 8 April (Week 15). Fresh basil, sampled in May as part of a United Kingdom wide survey of fresh herbs on retail sale, was found to be contaminated with S. Senftenberg. The HPA launched microbiological and epidemiological investigations to elucidate the causes of this outbreak.
Article
Cut lettuce dip-inoculated with Escherichia coli O157:H7 and Salmonella was treated with alkaline electrolyzed water (AlEW) at 20°C for 5min, and subsequently washed with acidic electrolyzed water (AcEW) at 20°C for 5min. Pre-treatment with AlEW resulted in an approximate 1.8log10cfu/g reduction of microbial populations, which was significantly (p⩽0.05) greater than microbial reductions resulting from other pre-treatment solutions, including distilled water and AcEW. Repeated AcEW treatment did not show a significant bacterial reduction. Mildly heated (50°C) sanitizers were compared with normal (20°C) or chilled (4°C) sanitizers for their bactericidal effect. Mildly heated AcEW and chlorinated water (200ppm free available chlorine) with a treatment period of 1 or 5min produced equal reductions of pathogenic bacteria of 3log10 and 4log10cfu/g, respectively. The procedure of treating with mildly heated AlEW for 5min, and subsequent washing with chilled (4°C) AcEW for period of 1 or 5min resulted in 3–4log10cfu/g reductions of both the pathogenic bacterial counts on lettuce. Extending the mild heat pre-treatment time increased the bactericidal effect more than that observed from the subsequent washing time with chilled AcEW. The appearance of the mildly heated lettuce was not deteriorated after the treatment. In this study, we have illustrated the efficacious application of AlEW as a pre-wash agent, and the effective combined use of AlEW and AcEW.
Article
A study was undertaken to investigate the cause of the bacteriostatic activity of fresh-cut spinach leaves against Listeria monocytogenes. L. monocytogenes was cultivated in pure tryptic soy broth for use as a monoculture, in tryptic soy broth containing 10 mg ml−1 of autoclaved or nonautoclaved freeze-dried spinach powder, and in tryptic soy broth in mixed cultures with various microorganisms isolated from fresh-cut spinach, including Pseudomonas fluorescens biovar I, P. fluorescens biovar III, Staphylococcus xylosus, and an undefined culture of mesophilic aerobic microorganisms (MAMs) isolated from freeze-dried spinach powder. These microorganisms were inoculated at 4.4 log CFU ml−1 and L. monocytogenes was inoculated at 2.4 and 4.4 log CFU ml−1. After 24 h of incubation at 30°C, the populations of the two inoculum levels L. monocytogenes increased to 9.0 and 9.6 log CFU ml−1 in the tryptic soy broth control, to 5.4 and 7.5 in nonautoclaved spinach powder cultures, and to 8.8 and 9.1 log CFU ml−1 in autoclaved spinach powder cultures; In mixed cultures with biovar I of P. fluorescens, L. monocytogenes increased to 7.4 and 8.6 log CFU ml−1; with biovar III to 7.7 and 9.1, with S. xylosus to 7.8 and 9.2, and with the MAMs to 7.1 and 8.0 CFU ml−1 in the low and high listerial inoculum cultures respectively. The LSD(0.05) of the means were 0.5 and 0.6, respectively. The freeze-dried spinach powder had an inhibitory effect on the growth of L. monocytogenes. The inhibitory effect was greatly decreased when the native microorganisms were almost eliminated by heating or irradiation. These results indicate that if L. monocytogenes is present as a contaminant on fresh-cut spinach, its growth probably will be restricted by native microorganisms.
Article
The presence of numerous genera of spoilage bacteria, yeasts and molds, and an occasional pathogen on fresh produce has been recognized for many years. Several outbreaks of human gastroenteritis have been linked to the consumption of contaminated fresh vegetables and, to a lesser extent, fruits. Salads containing raw vegetables have been identified as vehicles of traveler's diarrhea, an illness sometimes experienced by visitors to developing countries. Enterotoxigenic Escherichia coli is the most common cause of this illness. Enterohemorrhagic E. coli, specifically serotype O157:H7, has been implicated as the causative agent in an outbreak of gastroenteritis resulting from the consumption of cantaloupes. Outbreaks of salmonellosis in humans have been attributed to consumption of contaminated tomatoes, mustard cress, bean sprouts, cantaloupe, and watermelon. An onion-associated outbreak of Shigella flexneri gastroenteritis has recently been reported in the United States. Outbreaks of human listeriosis have been epidemiologically linked to the consumption of fresh cabbage and lettuce. Gastrointestinal illness caused by the consumption of raw vegetable seed sprouts contaminated by Bacillus cereus has been documented. The ability of Aeromonas hydrophila and Aeromonas sobria to produce several virulence factors has been documented and their fairly common occurrence in water raises concern over public health risks that may be associated with the consumption of salad vegetables, although their role as agents in foodborne illness has not been fully confirmed. Viruses are not likely to grow on contaminated vegetables and fruits but can survive long enough to cause life-threatening illness in humans. An increased per capita consumption of fresh and lightly processed produce in the United States and other countries, coupled with an increase in importation of produce to these countries from regions where standards for growing and handling produce may be compromised, has resulted in heightened interest in outbreaks of human gastroenteritis that may be attributed to contaminated fresh produce, particularly salad vegetables. Likewise methods of handling, processing, packaging, and distribution of fresh produce on a regional or local scale within countries are receiving attention in terms of identifying and controlling microbiological hazards. Hazard analysis critical control point (HACCP) programs are being developed in an effort to minimize the risk of illness associated with consumption of fresh produce. Examples of pathogenic microorganisms associated with fresh produce as well as procedures that can be used to reduce their incidence at the point of consumption are discussed.
Article
Summary Demand for fresh, convenient, minimally processed vegetables has led to an increase in the quantity and variety of products available to the consumer. Modified atmosphere packaging, in combination with refrigeration, is increasingly being employed as a mild preservation technique to ensure quality and storage-life. The fresh nature of these products, together with the mild processing techniques and subsequent storage conditions, have presented indigenous and pathogenic microorganisms with new ecosystems and potential infection vehicles; a number of outbreaks of foodborne disease being attributed to their consumption. Psychrotrophic pathogens and pathogens which are capable of maintaining an infectious potential under mild preservation regimes are of particular concern; Listeria monocytogenes, Aeromonas hydrophila and Clostridium botulinum being amongst the most notable. This review describes the processing, packaging and storage procedures involved in the production of minimally processed vegetables, and details their impact upon the survival and growth of associated pathogens. Gaps in our current understanding of the consequences of this novel technology for microbiological safety are highlighted.
Article
The effect of electrolyzed water on total microbial count was evaluated on several fresh-cut vegetables. When fresh-cut carrots, bell peppers, spinach, Japanese radish, and potatoes were treated with electrolyzed water (pH 6.8, 20 ppm available chlorine) by dipping, rinsing, or dipping/blowing, microbes on all cuts were reduced by 0.6 to 2.6 logs CFU/g. Rinsing or dipping/blowing were more effective than dipping. Electrolyzed water containing 50 ppm available chlorine had a stronger bactericidal effect than that containing 15 or 30 ppm chlorine for fresh-cut carrots, spinach, or cucumber. Electrolyzed water did not affect tissue pH, surface color, or general appearance of fresh-cut vegetables.
Article
Fresh-cut lettuce samples inoculated with S. Typhimurium, E. coli O157:H7 or L. monocytogenes were dipped into 300 ppm electrolyzed water (EW) at pH 4 to 9 and 30 °C for 5 min. The effects of treatment pH on bacterial reduction and visual quality of the lettuce were determined. The treatments at pH 4 and 8 resulted in the 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, and achieved a reduction of approximately 2 log CFU/g for above 3 bacteria.
Article
ABSTRACTASTM A-36 medium carbon steel, 110 copper, 3003-H14 aluminum, polyvinylchloride (PVC) type 1 and 304 stainless steel coupons were immersed in electrolyzed (EO) water, chlorine water, modified EO water and deionized water for a period of 8 days, and the properties of these types of water, weights and surface roughness of the coupons were monitored. EO water significantly increased (P < 0.05) the surface roughness of carbon steel, aluminum and copper with time; however, chlorine water, modified EO water and deionized water produced minimal changes on these materials. Regardless of the treatment water used, the surface roughness of stainless steel and PVC essentially remained the same. Carbon steel, copper, aluminum and stainless steel had a fair, good, good and outstanding corrosion resistance in EO water, respectively. Chlorine and modified EO water had a much less corrosive effect than EO water on all the materials tested.
Article
Modified-atmosphere packaging (MAP) and subsequent storage at refrigeration temperature has been developed over the last decade as an adequate technique to prolong high quality shelf-life of minimally processed vegetables. The MAP system employed should be carefully tailored to the physiological and microbiological characteristics of the product in order to achieve good quality, safe products. In the current investigation, controlled atmosphere conditions were employed that mimicked the packaging of fresh cut chicory endive under modified atmospheres in order to establish the microbiological characteristics. It was found that the modified-atmosphere conditions that were favourable for product quality, retarded growth of spoilage micro-organisms during storage at low temperature. Growth of the psychrotrophic pathogen Listeria monocytogenes, inoculated on the product, was not inhibited. The extent to which the pathogen grew depended on its initial number, type of chicory endive and size of the population of competitive spoilage microflora. Reducing the initial microbial load by disinfection could minimize microbial spoilage and improve the safety status of the product. However, L. monocytogenes grew better on disinfected produce than on non-disinfected or water-rinsed produce, indicating the practical importance of avoiding recontamination after disinfection.
Article
In 1995, the National Advisory Committee on Microbiological Criteria for Foods (Committee) was asked to investigate and characterize the association between cases for foodborne illness and fresh produce. The Committee was asked to provide recommendations that could be employed to reduce the risk of foodborne outbreaks associated with these commodities. In furtherance of this assignment, the Committee reviewed current epidemiologic data, the microbial ecology of the outbreak-associated organisms, and considered the current industry practices used for growing, harvesting, packing and distribution. An evaluation of these data provided a basis for hazard identification and the development of related control measures.The Committee has developed seven specific recommendations: Good Agricultural Practices (GAP) and Good Manufacturing Practices (GMP) should be developed that will provide guidance on those agricultural and processing steps that can reduce pathogen levels on fresh produce. While Hazard Analysis Critical Control Point Programs (HACCP) would be likely to provide the greatest assurance of the safety of these products, there are presently insufficient data upon which to develop such progams. Proactive and practical education programs are needed at all steps in the process, i.e., from the field to the consumer's plate. Additional data are needed to conduct effective risk assessments of the microbial hazards associated with fresh produce. Better product identification and tracing systems are needed for outbreak investigations. Research must be conducted to fill some of the current knowledge gaps in order that improved intervention strategies can be employed. Steps should be taken to ‘streamline’ approval processes for new technologies that will reduce/eliminate microbial hazards.
Article
The ability of peracetic acid and peroctanoic acid sanitizers to inactivate mixed-culture biofilms of a Pseudomonas sp. and Listeria monocytogenes on stainless steel was investigated. Types of biofilms tested included a 4-h attachment of the mixed-cell suspension and a 48-h biofilm of mixed culture formed in skim milk or tryptic soy broth. Biofilm-containing coupons were immersed in solutions of hypochlorite, peracetic acid, and peroctanoic acid either with or without organic challenge. Organic challenge consisted of either coating the biofilms with milk that were then allowed to dry, or adding milk to the sanitizing solution to achieve a 5% concentration. Surviving cells were enumerated by pouring differential agar directly on the treated surfaces. The peracid sanitizers were more effective than chlorine for inactivating biofilm in the presence of organic challenge. The 48-h mixed-culture biofilm grown in milk was reduced to less than 3 CFU/cm2 by 160 ppm of peracid sanitizer after 1 min of exposure. Peroctanoic acid was more effective than peracetic acid against biofilm cells under conditions of organic challenge. Pseudomonas and L. monocytogenes were inactivated to similar levels by the sanitizer treatments, even though Pseudomonas predominated in the initial biofilm population.
Article
This study investigates the properties of electrolyzed oxidizing (EO) water for the inactivation of pathogen and to evaluate the chemically modified solutions possessing properties similar to EO water in killing Escherichia coli O157:H7. A five-strain cocktail (10(10) CFU/ml) of E. coli O157:H7 was subjected to deionized water (control), EO water with 10 mg/liter residual chlorine (J.A.W-EO water), EO water with 56 mg/liter residual chlorine (ROX-EO water), and chemically modified solutions. Inactivation (8.88 log10 CFU/ml reduction) of E. coli O157:H7 occurred within 30 s after application of EO water and chemically modified solutions containing chlorine and 1% bromine. Iron was added to EO or chemically modified solutions to reduce oxidation-reduction potential (ORP) readings and neutralizing buffer was added to neutralize chlorine. J.A.W-EO water with 100 mg/liter iron, acetic acid solution, and chemically modified solutions containing neutralizing buffer or 100 mg/liter iron were ineffective in reducing the bacteria population. ROX-EO water with 100 mg/liter iron was the only solution still effective in inactivation of E. coli O157:H7 and having high ORP readings regardless of residual chlorine. These results suggest that it is possible to simulate EO water by chemically modifying deionized water and ORP of the solution may be the primary factor affecting microbial inactivation.
Article
These guidelines for the microbiological quality of ready-to-eat foods represent a revision and expansion of guidelines first published by the PHLS in September 1992 and revised in March 1996. The latest guidelines incorporate many of the constructive comments received from food examiners and other microbiologists within and outside the PHLS and from environmental health officers throughout the United Kingdom. This document reviews the changes and the reasons they were made and sets out the new guidelines. It also clarifies the role of food examiners in interpreting the microbiological results of formal samples.
Article
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.
Article
To identify the primary component responsible in electrolyzed oxidizing (EO) water for inactivation, this study determined the concentrations of hypochlorous acid (HOCl) and hypochlorite ions (OCl-) and related those concentrations to the microbicidal activity of the water. The ultraviolet absorption spectra were used to determine the concentrations of HOCl and OCl- in EO water and the chemical equilibrium of these species with change in pH and amperage. EO water generated at higher amperage contained a higher chlorine concentration. The maximum concentration of HOCl was observed around pH 4 where the maximum log reduction (2.3 log10 CFU/ml) of Bacillus cereus F4431/73 vegetative cells also occurred. The high correlation (r = 0.95) between HOCl concentrations and bactericidal effectiveness of EO water supports HOCl's role as the primary inactivation agent. Caution should be taken with standard titrimetric methods for measurement of chlorine as they cannot differentiate the levels of HOCl present in EO water of varying pHs.
Article
The chlorine loss of electrolyzed oxidizing (EO) water was examined during storage under different light, agitation, and packaging conditions. The chlorine loss of pH-adjusted EO water was also examined. Under open conditions, the chlorine loss through evaporation followed first-order kinetics. The rate of chlorine loss was increased about 5-fold with agitation, but it was not significantly affected by diffused light. Under closed conditions, the chlorine loss did not follow first-order kinetics, because the primary mechanism of chlorine loss may be self-decomposition of chlorine species rather than chlorine evaporation. The effect of diffused light was more significant compared to agitation after two months of storage under closed conditions. The chlorine loss of EO water and commercial chlorinated water decreased dramatically with the increase of pH from the acidic (pH 2.5) to the alkaline (pH 9.0) region.
Article
Effects of storage temperature (1, 5, and 10 degrees C) on growth of microbial populations (total aerobic bacteria, coliform bacteria, Bacillus cereus, and psychrotrophic bacteria) on acidic electrolyzed water (AcEW)-treated fresh-cut lettuce and cabbage were determined. A modified Gompertz function was used to describe the kinetics of microbial growth. Growth data were analyzed using regression analysis to generate "best-fit" modified Gompertz equations, which were subsequently used to calculate lag time, exponential growth rate, and generation time. The data indicated that the growth kinetics of each bacterium were dependent on storage temperature, except at 1 degrees C storage. At 1 degrees C storage, no increases were observed in bacterial populations. Treatment of vegetables with AcEW produced a decrease in initial microbial populations. However, subsequent growth rates were higher than on nontreated vegetables. The recovery time required by the reduced microbial population to reach the initial (treated with tap water [TW]) population was also determined in this study, with the recovery time of the microbial population at 10 degrees C being <3 days. The benefits of reducing the initial microbial populations on fresh-cut vegetables were greatly affected by storage temperature. Results from this study could be used to predict microbial quality of fresh-cut lettuce and cabbage throughout their distribution.
Article
A total of 890 samples of fresh produce obtained from Norwegian markets were examined in order to assess the bacteriological quality of the products and their potential public health risk. The samples comprised lettuce, pre-cut salads, growing herbs, parsley and dill, mushrooms and strawberries. The samples were analysed for the presence of thermotolerant coliform bacteria (TCB), Escherichia coli O157, Salmonella spp., Listeria monocytogenes, Staphylococcus spp., and Yersinia enterocolitica. Neither Salmonella spp. nor E. coli O157 were isolated. For all product groups included, TCB were isolated from a small proportion of samples. Three samples harboured L. monocytogenes; one of the isolates belonging to serogroup 1 (champignons) and two of the isolates belonging to serogroup 4 (Chinese leaves and strawberries). Staphylococci were isolated from a relatively large proportion of the samples of strawberries and mushrooms. However, only four isolates were identified as S. aureus (non-toxinogenic). By the use of PCR, the presence of Y. enterocolitica was indicated in a few of the samples of lettuce, whilst no positive samples were found using a culturing method. The study shows that the occurrence of pathogenic bacteria and TCB in the products analysed was quite low. Nevertheless, the results indicate that the type of products analysed may contain pathogenic bacteria and thereby represent a risk to the consumers in regard to food-borne diseases.
Article
The effectiveness of electrolyzed (EO) water at killing Enterobacter aerogenes and Staphylococcus aureus in pure culture was evaluated. One milliliter (approximately 10(9) CFU/ml) of each bacterium was subjected to 9 ml of EO water or control water (EO water containing 10% neutralizing buffer) at room temperature for 30 s. Inactivation (reduction of > 9 log10 CFU/ ml) of both pathogens occurred within 30 s after exposure to EO water containing approximately 25 or 50 mg of residual chlorine per liter. The effectiveness of EO water in reducing E. aerogenes and S. aureus on different surfaces (glass, stainless steel, glazed ceramic tile, unglazed ceramic tile, and vitreous china) was also evaluated. After immersion of the tested surfaces in EO water for 5 min without agitation, populations of E. aerogenes and S. aureus were reduced by 2.2 to 2.4 log10 CFU/ cm2 and by 1.7 to 1.9 log10 CFU/cm2, respectively, whereas washing with control water resulted in a reduction of only 0.1 to 0.3 log10 CFU/cm2. The washing of tested surfaces in EO water with agitation (50 rpm) reduced populations of viable cells on the tested surfaces to < 1 CFU/cm2. For the control water treatment with agitation, the surviving numbers of both strains on the tested surfaces were approximately 3 log10 CFU/cm2. No viable cells of either strain were observed in the EO water after treatment, regardless of agitation. However, large populations of both pathogens were recovered from control wash solution after treatment.
Article
A study was conducted to evaluate the efficacy of electrolyzed acidic water, 200-ppm chlorine water, and sterile distilled water in killing Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on the surfaces of spot-inoculated tomatoes. Inoculated tomatoes were sprayed with electrolyzed acidic water, 200-ppm chlorine water, and sterile distilled water (control) and rubbed by hand for 40 s. Populations of E. coli O157:H7, Salmonella, and L. monocytogenes in the rinse water and in the peptone wash solution were determined. Treatment with 200-ppm chlorine water and electrolyzed acidic water resulted in 4.87- and 7.85-log10 reductions, respectively, in Escherichia coli O157:H7 counts and 4.69- and 7.46-log10 reductions, respectively, in Salmonella counts. Treatment with 200-ppm chlorine water and electrolyzed acidic water reduced the number of L. monocytogenes by 4.76 and 7.54 log10 CFU per tomato, respectively. This study's findings suggest that electrolyzed acidic water could be useful in controlling pathogenic microorganisms on fresh produce.
Article
The influence of bacterial inoculation methods on the efficacy of sanitizers against pathogens was examined. Dip and spot inoculation methods were employed in this study to evaluate the effectiveness of acidic electrolyzed water (AcEW) and chlorinated water (200 ppm free available chlorine) against Escherichia coli O157:H7 and Salmonella spp. Ten pieces of lettuce leaf (5 by 5 cm) were inoculated by each method then immersed in 1.5 liters of AcEW, chlorinated water, or sterile distilled water for 1 min with agitation (150 rpm) at room temperature. The outer (abaxial) and inner (adaxial) surfaces of the lettuce leaf were distinguished in the spot inoculation. Initial inoculated pathogen population was in the range 7.3 to 7.8 log CFU/g. Treatment with AcEW and chlorinated water resulted in a 1 log CFU/g or less reduction of E. coli O157:H7 and Salmonella populations inoculated with the dip method. Spot inoculation of the inner surface of the lettuce leaf with AcEW and chlorinated water reduced the number of E. coli O157:H7 and Salmonella by approximately 2.7 and 2.5 log CFU/g, respectively. Spot inoculation of the outer surface of the lettuce leaf with both sanitizers resulted in approximately 4.6 and 4.4 log CFU/g reductions of E. coli O157:H7 and Salmonella, respectively. The influence of inoculation population size was also examined. Each sanitizer could not completely eliminate the pathogens when E. coli O157:H7 and Salmonella cells inoculated on the lettuce were of low population size (10(3) to 10(4) CFU/g), regardless of the inoculation technique.
Article
To determine the efficacy of neutral electrolyzed water (NEW) in killing Escherichia coli O157:H7, Salmonella enteritidis and Listeria monocytogenes, as well as nonpathogenic E. coli, on the surface of tomatoes, and to evaluate the effect of rinsing with NEW on the organoleptic characteristics of the tomatoes. The bactericidal activity of NEW, containing 444 or 89 mg l(-1) of active chlorine, was evaluated over pure cultures (8.5 log CFU ml(-1)) of the above-mentioned strains. All of them were reduced by more than 6 log CFU ml(-1) within 5 min of exposure to NEW. Fresh tomatoes were surface-inoculated with the same strains, and rinsed in NEW (89 mg l(-1) of active chlorine) or in deionized sterile water (control), for 30 or 60 s. In the NEW treatments, independent of the strain and of the treatment time, an initial surface population of about 5 log CFU sq.cm(-1) was reduced to <1 log CFU sq.cm(-1), and no cells were detected in the washing solution by plating procedure. A sensory evaluation was conducted to ascertain possible alterations in organoleptic qualities, yielding no significant differences with regard to untreated tomatoes. Rinsing in NEW reveals as an effective method to control the presence of E. coli O157:H7, S. enteritidis and L. monocytogenes on the surface of fresh tomatoes, without affecting their organoleptic characteristics. This indicates its potential application for the decontamination of fresh produce surfaces.
Article
An examination was made of the efficacy of acidic electrolyzed water (AcEW, 30 ppm free available chlorine), ozonated water (5 ppm ozone), and a sodium hypochlorite solution (NaOCl, 150 ppm free available chlorine) for use as potential sanitizers of cucumbers and strawberries. AcEW and NaOCl reduced the aerobic mesophiles naturally present on cucumbers within 10 min by 1.4 and 1.2 log CFU per cucumber, respectively. The reduction by ozonated water (0.7 log CFU per cucumber) was significantly less than that of AcEW or NaOCl (P < or = 0.05). Cucumbers washed in alkaline electrolyzed water for 5 min and then treated with AcEW for 5 min showed a reduction in aerobic mesophiles that was at least 2 log CFU per cucumber greater than that of other treatments (P < or = 0.05). This treatment was also effective in reducing levels of coliform bacteria and fungi associated with cucumbers. All treatments offered greater microbial reduction on the cucumber surface than in the cucumber homogenate. Aerobic mesophiles associated with strawberries were reduced by less than 1 log CFU per strawberry after each treatment. Coliform bacteria and fungi associated with strawberries were reduced by 1.0 to 1.5 log CFU per strawberry after each treatment. Microbial reduction was approximately 0.5 log CFU per strawberry greater on the strawberry surface than in the strawberry homogenate. However, neither treatment was able to completely inactivate or remove the microorganisms from the surface of the cucumber or strawberry.
Article
This study evaluated the efficacy of neutral electrolyzed water (NEW; 64.1 mg/liter of active chlorine) to reduce populations of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Listeria monocytogenes on plastic and wooden kitchen cutting boards. Its effectiveness was compared with that of a sodium hypochlorite solution (NaClO; 62.3 mg/liter of active chlorine). Inoculated portions of cutting boards were rinsed in either NEW or NaClO solutions, or deionized water (control). Plastic boards were rinsed for 1 min and wooden boards for 1 and 5 min. After each treatment, the surviving population of each strain was determined on the surface and in the soaking water. No significant difference (P > or = 0.05) was found between the final populations of each strain with regard to the treatment solutions (NEW or NaClO). However, a significant difference (P < or = 0.05) was revealed between surface materials after 1 min of washing. Whereas in plastic boards the initial bacterial populations were reduced by 5 log CFU/50 cm2, in wooden cutting boards they underwent a reduction of <3 log CFU/50 cm2. A 5-min exposure time yielded reductions of about 4 log CFU/50 cm2. The surviving populations of all bacteria in NEW and NaCIO washing solutions were <1 log CFU/ml after soaking both surfaces. This study revealed that NEW treatment is an effective method for reducing microbial contamination on plastic and wooden cutting boards. NEW efficacy was comparable to that of NaCIO, with the advantage of having a larger storage time.
Article
A survey of fresh and minimally-processed fruit and vegetables, and sprouts was conducted in several retail establishments in the Lleida area (Catalonia, Spain) during 2005–2006 to determine whether microbial contamination, and in particular potentially pathogenic bacteria, was present under these commodities. A total of 300 samples—including 21 ready-to-eat fruits, 28 whole fresh vegetables, 15 sprout samples and 237 ready-to-eat salads containing from one to six vegetables—were purchased from 4 supermarkets. They were tested for mesophilic and psychrotrophic aerobic counts, yeasts and moulds, lactic acid bacteria, Enterobacteriaceae, presumptive E. coli and Listeria monocytogenes counts as well as for the presence of Salmonella, E. coli O157:H7, Yersinia enterocolitica and thermotolerant Campylobacter.
Japan prepares as O157 strikes again Electrolyzed water as a disinfectant for fresh-cut vegetables
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Surface decontamination of fruits and vegetables eaten raw: a review
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International outbreak of Sal-monella Senftenberg in 2007 Guidelines for the micro-biological quality of some ready-to-eat foods sampled at the point of sale
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Fruits and vegetables Compendium of Methods for the Microbiological Examination of Foods
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Microbiological risk assessment on salads in Hong Kong
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Spinach and E. coli outbreak
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