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

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... It doesn't involve production, handling and transportation of using conventional chlorine (Hricova, Stephan, & Zweifel, 2008), economical because the EW production only involves water, salt and electricity. It can be generated on site when needed, being much less costly than conventional chlorine aspect of sanitiser generation, transporting and handling (Hricova et al., 2008;Huang, Hung, Hsu, Huang, & Hwang, 2008), safety thus it has been approved as a food additive in Japan, and the application on food was also approved by both U.S. Food and Drug Administration (FDA) and U.S. Department of Agriculture (USDA) (Hricova et al., 2008), and having strong sanitising effect because of major component being hypochlorous acid and there are some other effective components including free radicals, active oxygen, hydrogen peroxide and ozone gas, which are not existed in clorox and with higher oxidation-reduction potential (ORP) (Yang, Feirtag, & Diez-Gonzalez, 2013). However, at low pH, EW is corrosive, has a short shelf-life, and may be toxic to the operator (Ayebah & Hung, 2005;Waters, Tatum, & Hung, 2014;Xuan et al., 2016). ...
... Even though several studies have reported the bactericidal effects of both EW and NEW (Luo, Kim, Wang, & Oh, 2016;Park, Guo, Rahman, Ahn, & Oh, 2009;Thorn, Lee, Robinson, Greenman, & Reynolds, 2012;Zhang, Li, Jadeja, Fang, & Hung, 2016), few researchers have investigated the effects of processing factors on the performance of EW/NEW generators. Current commercial EW-producing units are quite large and not convenient for applications in households and small food industries (Yang et al., 2013). A portable, user-friendly NEW generator is necessary to meet the market demands and improve food safety. ...
... Escherichia coli (strain ATCC 25922), E. coli O157:H7 (strain C7927), and Listeria monocytogenes (strain ATCC BAA-839) were used in this study. The bactericidal activity of the EW samples was determined as previously reported with slight modifications Yang et al., 2013). Briefly, 24-h bacterial suspensions (10 mL each) were centrifuged (3000Âg, 4 C) for 10 min, and the resulting pellets were rinsed with 10 mL of sterile 0.1% peptone water (PW), centrifuged, and re-suspended in 10 mL of PW. ...
Article
The aim of this study was to develop and evaluate the characteristics and performance of a portable electrolytic sanitising unit. Free available chlorine (FAC), oxidation-reduction potential, and pH of elec-trolysed water were measured. Response surface methodology coupled with a Box-Behnken design was used to describe the input-output relationship and optimise FAC production. A partial catholyte solution was reintroduced to electrolysis for generating neutral electrolysed water. The result found that RuO 2-IrO 2 /TiO 2 electrode was very effective. A FAC concentration of 4 mg/L achieved >2 log CFU/mL reduction, while a FAC concentration of 40 mg/L achieved >6 log CFU/mL reduction in Escherichia coli O157:H7 and Listeria monocytogenes BAA-839. The developed sanitiser had a pH of 7.08 ± 0.08, and the commercial sanitiser had a pH of 3.77 ± 0.18. The developed sanitiser had similar bactericidal effects as the commercial sanitiser. The results revealed that the developed sanitising unit is promising for the control of foodborne pathogens.
... In the United States food safety is still a problem as food contamination by pathogens, which are harmful to humans, has been estimated to lead to about 3000 fatally and 128,000 cases of hospitalization each year [1]. Enterohemorrhagic Escherichia coli O157:H7, Listeria monocytogenes and Salmonella enterica are the top three pathogens responsible for foodborne illnesses and deaths [2,3]. ...
... In addition to causing food safety issues, pathogens also target farm animals causing diseases and deaths. In some cases livestock such as cattle serve as major reservoirs for pathogens specifically Escherichia coli O157:H7 resulting in contaminated meat, fruit and vegetables for human consumption [3]. Antimicrobial agents are used in animals to treat diseases, to safeguard the health and safety of farm animals, and to promote growth and feed efficiency [4]. ...
... Whereas some bacteria may be inherently resistant to different types of antimicrobial agents long-term exposure of such antimicrobial medicines to both humans and animals has resulted in increasing antimicrobial resistance in humans who depend on live stocks as sources of food [5]. Frequent use of antimicrobial agents for the treatment of infection generally result in declining levels of microflora in human gastrointestinal tract, causing the growth of pathogenic bacteria to reach high numbers [3]. ...
Article
Full-text available
The objective of this study was to determine the combined effect of locust bean, xanthan, agar, carrageenan-maltodextrin and pectin gums on the growth, bacterial survival, and susceptibility of foodborne pathogens. The combine effect five different gums and antimicrobial agents (Tetracycline, Doripenem, Imipenem, Cefixime, Cipropoxacin, Ceftazidime, Kanamycin and Meropenem) on susceptibility of foodborne pathogens was tested using disc diffusion method. Amongst gums tested, treatment with carrageenan-maltodextrin (52.00 ± 2.00 mm) and pectin (51.00 ± 1.00 mm) resulted in a twofold increased in susceptibility of Salmonella enterica to imipenem 10 µg, compared to the control (25.33 ± 1.00 mm). Treatment with locust bean and agar gums also led to a twofold increase in susceptibility of Salmonella enterica to cefixime and xanthan also increased susceptibility Escherichia coli O157:H7 to doripenem. Addition of gums led to a slight increase or decrease on bacterial growth in treatment compared to control. Bacterial survival decreased in the presence of all gums during refrigerated storage with pectin producing a log 2.68 ± 0.10 CFUml-1 reduction. Tested gums could potentially be used in combination with antimicrobial medicines to improve their efficacy in the treatment of Salmonella enterica, Staphylococcus aureus, Listeria monocytogenes and Escherichia coli O157:H7 infections. Our findings could potentially lead to synergistic use of gums and antimicrobial agents to enhance the treatment and reduce recovery period of foodborne infections leading to less dependence on antimicrobial medicines and subsequently promoting health.
... In general, NEW is produced by mixing the catholyte with EW produced by a divided electrolytic cell, with diluted NaCl solution as the electrolyte (Yang, Feirtag, & Diez-Gonzalez, 2013;Zhao, Zhang, & Yang, 2017). With same electrolyte, another method to produce NEW involves using 3 tubs with 2-membrane partitions and 4 sheets of electrodes in the electrolytic cells (Umimoto, Fujiwara, Nagata, & Yanagida, 2013). ...
... There are some reports of the continuous production of NEW using a commercial electrolysis unit (Gil et al., 2015;Guentzel, Lam, Callan, Emmons, & Dunham, 2008;Hao et al., 2012;Monnin, Lee, & Pascall, 2012). However, these current commercial NEW-producing units are quite large and are not convenient for households and small food industries (Yang et al., 2013). ...
... Escherichia coli O157:H7 (strain C7927), and Listeria monocytogenes (strain ATCC BAA-839) were used in this study. The bactericidal activity of the NEW samples was determined as previously reported, with slight modifications (Yang et al., 2013). Briefly, 24-hr bacterial suspensions (10 mL each in TSB) were centrifuged (3000 × g, 4°C) for 10 min, and the resulting pellets were rinsed with 10 mL of sterile 0.1% peptone water (PW), centrifuged, and resuspended in 10 mL of PW. ...
Article
We developed a portable flow-through, electrochemical sanitizing unit to produce near neutral pH electrolyzed water (producing NEW). Two methods of redirecting cathode yields back to the anode chamber and redirecting anode yields the cathode chamber were used. The NEW yields were evaluated, including: free available chlorine (FAC), oxidation-reduction potential (ORP), and pH. The performances of 2 electrodes (RuO2 -IrO2 /TiO2 and IrO2 -Ta2 O5 /TiO2 ) were investigated. The unit produced NEW at pH 6.46 to 7.17, an ORP of 805.5 to 895.8 mV, and FAC of 3.7 to 82.0 mg/L. The NEW produced by redirecting cathode yields had stronger bactericidal effects than the NEW produced by redirecting anode yields or NEW produced by mixing the commercial unit's anode and cathode product (P < 0.05). Electron spin resonance results showed hydroxyl free radicals and superoxide anion free radicals were present in the NEW produced by developed unit. The NEW generator is a promising sanitizing unit for consumers and the food industry to control foodborne pathogens. Practical application: Current commercial NEW-producing units are quite large and are not convenient for family using. The developed portable flow-through, NEW-producing unit has great potential in a wide range of applications, such as organic farm, households, and small food industries. The examined sanitizing treatments showed effective control of Escherichia coli O157:H7 and Listeria monocytogenes.
... It doesn't involve production, handling and transportation of using conventional chlorine (Hricova, Stephan, & Zweifel, 2008), economical because the EW production only involves water, salt and electricity. It can be generated on site when needed, being much less costly than conventional chlorine aspect of sanitiser generation, transporting and handling (Hricova et al., 2008;Huang, Hung, Hsu, Huang, & Hwang, 2008), safety thus it has been approved as a food additive in Japan, and the application on food was also approved by both U.S. Food and Drug Administration (FDA) and U.S. Department of Agriculture (USDA) (Hricova et al., 2008), and having strong sanitising effect because of major component being hypochlorous acid and there are some other effective components including free radicals, active oxygen, hydrogen peroxide and ozone gas, which are not existed in clorox and with higher oxidation-reduction potential (ORP) (Yang, Feirtag, & Diez-Gonzalez, 2013). However, at low pH, EW is corrosive, has a short shelf-life, and may be toxic to the operator (Ayebah & Hung, 2005;Waters, Tatum, & Hung, 2014;Xuan et al., 2016). ...
... Even though several studies have reported the bactericidal effects of both EW and NEW (Luo, Kim, Wang, & Oh, 2016;Park, Guo, Rahman, Ahn, & Oh, 2009;Thorn, Lee, Robinson, Greenman, & Reynolds, 2012;Zhang, Li, Jadeja, Fang, & Hung, 2016), few researchers have investigated the effects of processing factors on the performance of EW/NEW generators. Current commercial EW-producing units are quite large and not convenient for applications in households and small food industries (Yang et al., 2013). A portable, user-friendly NEW generator is necessary to meet the market demands and improve food safety. ...
... Escherichia coli (strain ATCC 25922), E. coli O157:H7 (strain C7927), and Listeria monocytogenes (strain ATCC BAA-839) were used in this study. The bactericidal activity of the EW samples was determined as previously reported with slight modifications Yang et al., 2013). Briefly, 24-h bacterial suspensions (10 mL each) were centrifuged (3000Âg, 4 C) for 10 min, and the resulting pellets were rinsed with 10 mL of sterile 0.1% peptone water (PW), centrifuged, and re-suspended in 10 mL of PW. ...
Article
The aim of this study was to develop and evaluate the characteristics and performance of a portable electrolytic sanitising unit. Free available chlorine (FAC), oxidation-reduction potential, and pH of elec-trolysed water were measured. Response surface methodology coupled with a Box-Behnken design was used to describe the input-output relationship and optimise FAC production. A partial catholyte solution was reintroduced to electrolysis for generating neutral electrolysed water. The result found that RuO 2-IrO 2 /TiO 2 electrode was very effective. A FAC concentration of 4 mg/L achieved >2 log CFU/mL reduction, while a FAC concentration of 40 mg/L achieved >6 log CFU/mL reduction in Escherichia coli O157:H7 and Listeria monocytogenes BAA-839. The developed sanitiser had a pH of 7.08 ± 0.08, and the commercial sanitiser had a pH of 3.77 ± 0.18. The developed sanitiser had similar bactericidal effects as the commercial sanitiser. The results revealed that the developed sanitising unit is promising for the control of foodborne pathogens.
... However, the NEW used was mainly produced by current commercial NEW-producing units with NaCl or NaCl mixed with HCl as electrolytes. These units are quite large so that they are not convenient for households and small food industries (Zhang, Zhou, Chen, & Yang, 2017;Yang, Feirtag, & Diez-Gonzalez, 2013). NaHCO 3 is a food additive that is allowed for application on various commodities. ...
... E. coli O157:H7 (strain C7927), and L. monocytogenes (strain ATCC BAA-839) were used in this study. The bactericidal activity of the NEW samples was determined as previously reported, with slight modifications (Yang et al., 2013;Zhao, Zhang, & Yang, 2017). Briefly, 24-h bacterial suspensions (10 mL each) were centrifuged (3000 × g, 4°C) for 10 min, and the resulting pellets were rinsed with 10 mL of sterile 0.1% peptone water (PW), centrifuged, and re-suspended in 10 mL of PW. ...
Article
A novel method was used to produce near neutral pH electrolysed water (NEW) by developing a portable electrochemical sanitising unit that uses diluted sodium chloride and sodium bicarbonate solution (6 mM) as electrolytes. The unit produced NEW at pH 5.70 to 7.1, an oxidation-reduction potential of 802.2–933.8 mV, and free available chlorine (FAC) of 3.3–70 mg/L. NEW produced by the unit with NaCl 10 g/L showed stronger bactericidal effects than NEW produced by mixing the anode and cathode product from commercial unit's (P < 0.05): 2.03 log colony forming units (CFU)/mL reductions compared with 1.66 log CFU/mL reductions. To further understand the sanitising result, electron spin resonance and flow cytometry were performed. The results showed NEW produced by the developed unit induced 82.2% injured cells compared with 54.4% by NEW without detected free radicals. Overall, the current efficiency and power consumption were increased during NEW generation for NEW using sodium bicarbonate compared with sole NEW. The developed NEW generator is a promising sanitising unit for consumers and food industry to control foodborne pathogens.
... Acidic electrolysed water (AEW) can be applied on food and food contact surface, the active oxidising components and chlorines in AEW make it an effective sanitiser against foodborne pathogens including E. coli O157:H7, Salmonella and Listeria monocytogenes (Park, Alexander, Taylor, Costa, & Kang, 2008;Yang, Feirtag, & Diez-Gonzalez, 2013). When the free available chlorine concentration (FAC) of AEW is less than 5 mg/L, it complies with the regulation limit for treatment of drinking water and can be considered as safe (WHO, 2011), while up to 4 mg/L is permitted for organic food sanitisation. ...
... The microorganisms were dried on SS surface according to the method of Yang et al. (2013) with modification. Microorganisms (25 ml) were inoculated as a spot on sterile SS coupon (1 cm diameter, 0.7 mm thickness) at approximated level of 8.4 log CFU/ coupon and dried in laminar flow cabinet for 3 h. ...
... Acidic electrolysed water (AEW) can be applied on food and food contact surface, the active oxidising components and chlorines in AEW make it an effective sanitiser against foodborne pathogens including E. coli O157:H7, Salmonella and Listeria monocytogenes (Park, Alexander, Taylor, Costa, & Kang, 2008;Yang, Feirtag, & Diez-Gonzalez, 2013). When the free available chlorine concentration (FAC) of AEW is less than 5 mg/L, it complies with the regulation limit for treatment of drinking water and can be considered as safe (WHO, 2011), while up to 4 mg/L is permitted for organic food sanitisation. ...
... The microorganisms were dried on SS surface according to the method of Yang et al. (2013) with modification. Microorganisms (25 ml) were inoculated as a spot on sterile SS coupon (1 cm diameter, 0.7 mm thickness) at approximated level of 8.4 log CFU/ coupon and dried in laminar flow cabinet for 3 h. ...
Article
Carvacrol is an effective antimicrobial agent originated from essential oils, this natural antimicrobial agent has higher consumer acceptance compared to chemical agents. Due to the low solubility of carvacrol in water, carvacrol was delivered as a nanoemulsion. A carvacrol nanoemulsion contained 3.5% (w/w) oil phase (1% carvacrol and 2.5% corn oil, w/w) and 3.5% (w/w) Tween 80 was produced by ultrasonification at 10 min using 100% amplitude; the median particle size was 309 ± 19 nm. The nanoemulsion was shelf-life stable for 1 month without any significant changes in particle size. When applied against Escherichia coli ATCC 25922 and Pichia pastoris GS115 growth in nutrient broth, carvacrol nanoemulsion (0.5% w/w carvacrol) achieved 3 log reductions of microorganisms. When microorganisms were fixed and dried on stainless steel coupon surface, the carvacrol nanoemulsion treatment was more effective on E. coli than P. pastoris with about 5 and 0.3 log reduction of viable count, respectively. The native microflora on shredded cabbages was challenged by combining carvacrol nanoemulsion and acidic electrolysed water (AEW) that contained 4 mg/L free available chlorine (FAC). The treatment reduced about 0.5 log of aerobic mesophilic and psychrotropic bacteria counts and the antimicrobial activity of carvacrol nanoemulsion and AEW lasted up to 2 days. The results indicated that carvacrol nanoemulsion is promising in controlling the safety of fresh-cut vegetables.
... However, the NEW used was mainly produced by current commercial NEW-producing units with NaCl or NaCl mixed with HCl as electrolytes. These units are quite large so that they are not convenient for households and small food industries (Zhang, Zhou, Chen, & Yang, 2017;Yang, Feirtag, & Diez-Gonzalez, 2013). NaHCO 3 is a food additive that is allowed for application on various commodities. ...
... E. coli O157:H7 (strain C7927), and L. monocytogenes (strain ATCC BAA-839) were used in this study. The bactericidal activity of the NEW samples was determined as previously reported, with slight modifications (Yang et al., 2013;Zhao, Zhang, & Yang, 2017). Briefly, 24-h bacterial suspensions (10 mL each) were centrifuged (3000 × g, 4°C) for 10 min, and the resulting pellets were rinsed with 10 mL of sterile 0.1% peptone water (PW), centrifuged, and re-suspended in 10 mL of PW. ...
Article
A novel method was used to produce near neutral pH electrolysed water (NEW) by developing a portable electrochemical sanitising unit that uses diluted sodium chloride and sodium bicarbonate solution (6 mM) as electrolytes. The unit produced NEW at pH 5.70 to 7.1, an oxidation-reduction potential of 802.2-933.8 mV, and free available chlorine (FAC) of 3.3-70 mg/L. NEW produced by the unit with NaCl 10 g/L showed stronger bactericidal effects than NEW produced by mixing the anode and cathode product from commercial unit's (P < 0.05): 2.03 log colony forming units (CFU)/mL reductions compared with 1.66 log CFU/mL reductions. To further understand the sanitising result, electron spin resonance and flow cytometry were performed. The results showed NEW produced by the developed unit induced 82.2% injured cells compared with 54.4% by NEW without detected free radicals. Overall, the current efficiency and power consumption were increased during NEW generation for NEW using sodium bicarbonate compared with sole NEW. The developed NEW generator is a promising sanitising unit for consumers and food industry to control foodborne pathogens.
... Low concentration electrolysed water (LcEW) has been increasingly used as a disinfectant in food decontamination due to its economic cost, low corrosivity and convenient quick on-site production (Zhang et al., 2016;Zhao et al., 2017). The strong disinfection efficacy of LcEW against microorganisms has been demonstrated by many previous studies (Liu et al., 2017a;Sow et al., 2017;Yang et al., 2013;. The bactericidal effect of LcEW is partially due to its high oxidation potential (ORP) (940-1010 mV), which is outside the preferable redox potential range of most microorganisms (Park et al., 2004;Park et al., 2009). ...
... The use of approved antimicrobial agents presents some issues related to disposal and worker's safety [138], and scientific evidence indicates that biocides may contribute to the increased occurrence of antibiotic resistant bacteria [98]. Therefore, the possible consequences to human health of biocide tolerance in the food industry are very relevant. ...
Article
The presence of undesirable biofilms on food processing contact surfaces may lead to: (1) transmission of diseases; (2) food spoilage; (3) shortened time between cleaning events; (4) contamination of product by nonstarter bacteria; (5) metal corrosion in pipelines and tanks; (6) reduced heat transfer efficacy or even obstruction of the heat equipment. Despite the significant problems caused by biofilms in the food industry, biofilm formation in these environments is still poorly understood and effective control of biofilms remains challenging. Although it is understood that cell attachment and biofilm formation are influenced by several factors, including type of strain, chemical-physical properties of the surface, temperature, growth media and the presence of other microorganisms, some conflicting statements can be retrieved from the literature and there are no general trends yet that allow us to easily predict biofilm development. It is likely that still unexplored interaction of factors may be more critical than the effect of a single parameter. New alternative biofilm control strategies, such as biocontrol, use of enzymes and phages and cell-to-cell communication interference, are now available that can reduce the use of chemical agents. In addition, as preventing biofilm formation is a more efficient strategy than controlling mature biofilm, the use of surface-modified materials have been suggested. These strategies may better reveal their beneficial potential when the ecological complexity of biofilms in food environments is addressed.
... When many chemical sanitisers are banned or limited to be applied for organic food because of the strict regulations (NOP 5026, 2011;Zhang & Yang, 2017), electrolysed water (EW), which is produced by the electrolysis of a dilute sodium chloride solution, is gaining ever-increasing popularity in food processing due to its environmentally-friendly nature and strong sanitising effect (Hricova, Stephan, & Zweifel, 2008;Rahman, Ding, & Oh, 2010;Yang, Feirtag, & Diez-Gonzalez, 2013). Compared to acidic electrolysed water, neutralised electrolysed water (NEW) is milder and safer without significantly affecting foods' nutritional values and quality. ...
... It has been shown that the form of ACC present can alter as the pH changes, which is highly related to the antimicrobial activity of AEW (Xiong et al. 2012(Xiong et al. , 2014. However, even at approximately the same pH value, AEW with different ACC values can also exhibit different disinfection abilities (Yang et al. 2013a). A previous study has also shown a high level of correlation (r = 0.95) between HOCl concentration and the bactericidal effectiveness of AEW (Len et al. 2000). ...
Article
The efficacy of acidic electrolyzed water (AEW) for reducing total bacteria, coliforms, yeast and mold counts on commercial mung bean sprouts was investigated. The impact of pH, available chlorine concentration (ACC) and the cleaning method on antimicrobial efficacy of AEW was studied. AEW with a pH of 4.47 reduced the total bacterial, coliform, and yeast and mold counts on mung bean sprouts by 1.23, 1.42 and 1.25 log CFU/g, respectively. The efficacy of AEW increased with increasing ACC, and further studies showed that its antimicrobial ability was based on a combination of pH and ACC values. Cleaning using ultrasonic waves enhanced the antimicrobial activity of electrolyzed water, achieving reduction of 2.46, 2.13 and 2.92 log CFU/g for total bacterial, yeast and mold, and coliform counts, respectively. These results have indicated that using ultrasonic waves as a cleaning method, combined with AEW, could be a promising way to reduce the microbial populations on mung bean sprouts.
... Many studies have shown that EW can efficiently inactivate pathogens (Luo & Oh, 2016;Park, Guo, Rahman, Ahn, & Oh, 2009;Yang, Feirtag, & Diez-Gonzalez, 2013;. However, there are only a few reports on its mechanism of action. ...
... The use of low concentration electrolysed water (LcEW), which possesses several potential advantages over traditional chlorine-based sanitisers, represents a promising alternative (Ding et al., 2015;Huang, Hung, Hsu, Huang, & Hwang, 2008;Yang, Feirtag, & Diez-Gonzalez, 2013;Zhao, Zhang, & Yang, 2017). The bactericidal effect of LcEW is partially due to its high oxidation potential (ORP), which could cause the modification of metabolite fluxes and electron flow in cells (Huang et al., 2008). ...
Article
The effects of low-concentration electrolysed water (LcEW) (4 mg/L free available chlorine) combined with mild heat on the safety and quality of fresh organic broccoli (Brassica oleracea) were evaluated. Treatment with LcEW combined with mild heat (50 C) achieved the highest reduction in naturally occurring microorganisms and pathogens, including inoculated Escherichia coli O157:H7 and Listeria monocytogenes (P < 0.05). In terms of the antioxidant content of the treated broccoli, the total phenolic levels and ferric reducing antioxidant power remained unchanged; however, the oxygen radical absor-bance capacity of the treated broccoli was higher than that of the untreated control. In addition, mild heat treatment resulted in an increase in firmness. The increased firmness was attributed to changes in the pectin structure, including the assembly and dynamics of pectin. The results revealed that mild heat induced an antiparallel orientation and spontaneous aggregation of the pectin chains. This study demonstrated that LcEW combined with mild heat treatment was effective to reduce microbial counts on fresh organic broccoli without compromising the product quality.
... In the United States, 31 foodborne pathogens caused about 9.4 million illness, 56,000 hospitalizations, and 1300 deaths each year (Scallan et al., 2011). Salmonella enterica, Listeria monocytogenes and enterohemorrhagic Escherichia coli O157:H7 are on the top three of the lists of bacterial pathogens responsible for foodborne illnesses (Scallan et al., 2011;Yang, Feirtag, & Diez-Gonzalez, 2013). ...
... However, higher levels of enzymatic activity in sprouted grain may promote fungal growth during storage or negatively affect the food-processing characteristics of cereal (Mergoum et al. 2004). Contamination of seeds can occur pre-and post-harvest and during germination and sprouting when conditions are optimal for microorganism growth (Yang et al. 2013). Therefore, measures must be taken to eliminate pathogenic microorganisms from malted or sprouted seeds. ...
Article
Triticale malt can be used as a source of enzymes or as a raw material for the production of functional foods. In this study, triticale malt was produced by soaking triticale seeds either in tap water (TW) or slightly acidic electrolyzed water (SAEW) and then rinsing with TW, SAEW, or alkaline electrolyzed water (AEW). We determined the length of the hypocotyl of triticale malt and the activities of α-amylase, phytase, proteases, and lipase during 4 days of germination. The electrolyzed water (EW) treatments promoted the growth of triticale malt. On the 4th day of germination, the hypocotyl length of triticale malt soaked in TW and watered with SAEW was 24.57% longer than that of triticale malt soaked and watered with TW. The α-amylase, phytase, acidic protease, and lipase activities of triticale malt soaked in SAEW and watered with AEW were high on the 4th germination day (0.11, 1.24 × 10⁻⁴, 0.62, and 0.51 units/mg protein, respectively). The main finding of this study is that the use of EW, especially during the soaking procedure, may be a promising way to obtain triticale malt with high enzyme activity for use in the production of functional foods.
... Low concentration electrolysed water (LcEW) has been increasingly used as a disinfectant in food decontamination due to its economic cost, low corrosivity and convenient quick on-site production (Zhang et al., 2016;Zhao et al., 2017). The strong disinfection efficacy of LcEW against microorganisms has been demonstrated by many previous studies (Liu et al., 2017a;Sow et al., 2017;Yang et al., 2013;. The bactericidal effect of LcEW is partially due to its high oxidation potential (ORP) (940-1010 mV), which is outside the preferable redox potential range of most microorganisms (Park et al., 2004;Park et al., 2009). ...
Article
Bactericidal effects of low concentration electrolysed water (LcEW) on microorganisms are previously well reported ; however, the inactivation mechanism of EW is not understood. The lethal and sublethal injuries of L. monocytogenes and L. innocua by EW treatments were determined and the metabolic profile changes for L. in-nocua were characterised using nuclear magnetic resonance (NMR). Microbial metabolomics approach combined with multivariate data analyses was used to interpret the cellular chemical fingerprints of L. innocua. The relative amount of intracellular reactive oxygen species (ROS) was assayed using 2′,7-dichlorodihydrofluorescein dia-cetate (H 2 DCFDA). The results showed that the proportion of the sublethally injured microbial cells L. mono-cytogenes and L. innocua increased from 40% to 70% and from 35% to 65%, respectively, when the free available chlorine (FAC) of LcEW increased from 2 to 8 mg/L. Overall, 36 low-molecular-weight metabolic compounds in L. innocua extracts were characterised by NMR spectroscopy. EW perturbation resulted in a drastic and multitude disruption across a wide range of biochemical process including peptidoglycan synthesis, nucleotides bio-synthesis and amino acid metabolism. Elevated levels of α-ketoglutarate and succinate implicated the enhanced glutamate decarboxylase (GAD) system and γ-aminobutyric acid (GABA) shunt for the protection against oxi-dative stress. These findings provided the comprehensive insights into the metabolic response of Listeria to EW oxidative stress and can serve as a basis for better utilisation for sanitisation.
... When many chemical sanitisers are banned or limited to be applied for organic food because of the strict regulations (NOP 5026, 2011;Zhang & Yang, 2017), electrolysed water (EW), which is produced by the electrolysis of a dilute sodium chloride solution, is gaining ever-increasing popularity in food processing due to its environmentally-friendly nature and strong sanitising effect (Hricova, Stephan, & Zweifel, 2008;Rahman, Ding, & Oh, 2010;Yang, Feirtag, & Diez-Gonzalez, 2013). Compared to acidic electrolysed water, neutralised electrolysed water (NEW) is milder and safer without significantly affecting foods' nutritional values and quality. ...
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.
... In the United States, 31 foodborne pathogens caused about 9.4 million illness, 56,000 hospitalizations, and 1300 deaths each year (Scallan et al., 2011). Salmonella enterica, Listeria monocytogenes and enterohemorrhagic Escherichia coli O157:H7 are on the top three of the lists of bacterial pathogens responsible for foodborne illnesses (Scallan et al., 2011;Yang, Feirtag, & Diez-Gonzalez, 2013). ...
Article
Berries such as blueberry, blackberry and raspberry possess several biological activities including anti-microbial and nutritional effects. In this study, the antimicrobial activities of blackberry (Rubus fruticosus) juice against foodborne pathogens including Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli O157:H7 were investigated. Inhibition of growth of these foodborne pathogens was measured in broth (LuriaeBertani broth for E. coli O157:H7 and S. Typhimurium, and brain heart infusion broth for L. monocytogenes), skim milk and whole milk supplemented with 10% blackberry juice at different time points (0, 24, 48 and 72 h). The effects of blackberry juice on the growth of Lactobacillus casei, Lactobacillus plantarum and Lactobacillus rhamnosus were also investigated in ManeRogosa eSharpe (MRS) broth and skim and whole milk supplemented with blackberry juice. The growth of L. monocytogenes, S. Typhimurium and E. coli O157:H7 were significantly inhibited by blackberry juice by 1e3 logs in both milk and broth. We also observed that the growths of Lactobacillus strains were significantly stimulated (1e4 logs CFU/mL) by blackberry juice in both milk and MRS broth. These data clearly demonstrate that diluted blackberry juice can be used as a preservative in food processing and a preventive in foodborne infections as a natural antimicrobial.
... Some examples of the very recently fresh vegetable sanitisation techniques which have been used or studied for fresh produce are: different types of electrolysed water (EW) (Afari, Hung, King, & Hu, 2016;Yang, Feirtag, & Diez-Gonzalez, 2013;Zhang, Cao, Hung, & Li, 2016); 0.8%e5% H 2 O 2 (Lopez-Galvez, Ragaert, Palermo, Eriksson, & Devlieghere, 2013;Lu, Joerger, & Wu, 2014;Van Haute, Tryland, Veys, & Sampers, 2015); 1%e2% organic acid (Tirawat, Phongpaichit, Benjakul, & Sumpavapol, 2016;Bermúdez-Aguirre & Barbosa-C anovas, 2013); and also some combinations of these methods, such as combination of 100 mg/L EW with 1% citric acid (CA) (Park, Guo, Rahman, Ahn, & Oh, 2009), combination of 1% organic acids with 2% H 2 O 2 (Lopez- Galvez et al., 2013). However, these techniques use too high concentration of sanitisers, which can't satisfy the requirement for processing fresh organic produce. ...
Article
Potential organic compatible sanitisers including electrolysed water (EW, 4 mg/L free available chlorine (FAC)), citric acid (0.6%), H 2 O 2 (1%), and their combinations were applied on organic and conventional fresh-cut lettuce (Lactuca sativa Var crispa L.) to evaluate their effects on microbiological safety, physi-cochemical parameters and sensory analysis (including raw sample and boiled sample). The combination of 1% H 2 O 2 with 0.6% citric acid led to the highest reductions of microbial loads (2.26 log CFU/g for aerobic mesophilic count (AMC) and 1.28 log CFU/g for yeasts and moulds); however, it also caused the highest electrolyte leakage rate (3.11% vs. 0.91% for control). The combination of EW with 1% H 2 O 2 achieved 1.69 and 0.96 log CFU/g reductions for AMC and yeasts and moulds, respectively with elec-trolyte leakage rate of 1.41%. In terms of the content of polyphenolic compounds, firmness, colour and raw material sensory analysis, there were no significant differences among different treatments, and between organic and conventional counterparts. The results suggest that 1% H 2 O 2 combined with 4 mg/L EW is a promising approach for treating organic fresh-cut lettuce.
... Many studies have shown that EW can efficiently inactivate pathogens (Luo & Oh, 2016;Park, Guo, Rahman, Ahn, & Oh, 2009;Yang, Feirtag, & Diez-Gonzalez, 2013;. However, there are only a few reports on its mechanism of action. ...
Article
Electrolysed water (EW) is an activated liquid with a high oxidation-reduction potential. EW causes oxidative damage to pathogenic microorganisms and as a result, may have utility in the food industry. The molecular mechanism of EW's action is not understood. In this study, we exposed Escherichia coli ATCC 25922 to a sub-lethal concentration of EW and examined structural and metabolic changes. Atomic force microscopy revealed that EW caused damage to E. coli membranes. To understand the metabolic responses to EW perturbations in of E. coli, multivariate data analysis of NMR spectroscopy demonstrated that EW significantly influenced the metabolic state. This included reducing nucleotide and amino acid biosynthesis, suppressing energy-associated metabolism, altering osmotic adjustment, and promoting fatty acid metabolism. The results enrich our understanding of E. coli metabolic changes caused by EW perturbation and support the effectiveness of the NMR metabolomics as a valuable tool to analyse and evaluate such a complex biological system.
... The use of low concentration electrolysed water (LcEW), which possesses several potential advantages over traditional chlorine-based sanitisers, represents a promising alternative (Ding et al., 2015;Huang, Hung, Hsu, Huang, & Hwang, 2008;Yang, Feirtag, & Diez-Gonzalez, 2013;Zhao, Zhang, & Yang, 2017). The bactericidal effect of LcEW is partially due to its high oxidation potential (ORP), which could cause the modification of metabolite fluxes and electron flow in cells (Huang et al., 2008). ...
Article
The effects of low-concentration electrolysed water (LcEW) (4 mg/L free available chlorine) combined with mild heat on the safety and quality of fresh organic broccoli (Brassica oleracea) were evaluated. Treatment with LcEW combined with mild heat (50 C) achieved the highest reduction in naturally occurring microorganisms and pathogens, including inoculated Escherichia coli O157:H7 and Listeria monocytogenes (P < 0.05). In terms of the antioxidant content of the treated broccoli, the total phenolic levels and ferric reducing antioxidant power remained unchanged; however, the oxygen radical absor-bance capacity of the treated broccoli was higher than that of the untreated control. In addition, mild heat treatment resulted in an increase in firmness. The increased firmness was attributed to changes in the pectin structure, including the assembly and dynamics of pectin. The results revealed that mild heat induced an antiparallel orientation and spontaneous aggregation of the pectin chains. This study demonstrated that LcEW combined with mild heat treatment was effective to reduce microbial counts on fresh organic broccoli without compromising the product quality.
... Neutral EW (NEW) is produced using different protocols [9]. It could be generated when the electrolytic cell does not have a separative membrane [20] or by mixing the catholyte with a diluted NaCl solution [22,23]. It has been reported that NEW is more stable and keeps its antibacterial activity after storage in comparison to AEW and BEW [24,25]. ...
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.
... Electrolyzed water is normally obtained by the electrolysis of a dilute sodium chloride solution. The electrolyzed water is gaining increasing popularity because of a strong sanitizing effect and easy production without polluting the environment (Yang, Feirtag, & Diez-Gonzalez, 2013). The combined treatment of ultrasonication (37 kHz, 80 W) and electrolyzed water (pH = 7.0, free available chlorine = 4 mg/L) was first adopted to inactive E. coli, Pichia pastoris, and Aureobasidium pullulans biofilms formed on stainless-steel coupons as reported in Zhao, Zhang, and Yang (2017). ...
Article
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Electrolyzed water (EW) shows great potential as a green and economical sanitation solution for the food industry. However, only limited studies have investigated the optimum electrolysis parameters and the bactericidal effect of acidic electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW). Here, the Box-Behnken experimental design was used to identify the optimum parameters. The tests were conducted with different types of electrodes, electrical voltages, electrolysis times, and NaCl concentrations. There were no obvious differences observed in the physico-chemical properties of EW when different electrodes were used. However, stainless steel was chosen as it meets most of the selection criteria. The best-optimized conditions for AcEW were at 11.39 V, 0.65 wt.% NaCl, and 7.23 min, while the best-optimized conditions for AlEW were at 10.32 V, 0.6 wt.% NaCl, and 7.49 min. The performance of the optimum EW (AcEW and AlEW) compared with commercial cleaning detergents for the food industry was then evaluated. The bactericidal activity of AcEW and AlEW was examined against Escherichia coli ATCC 10536 at different temperatures (30 • C and 50 • C) for 30 s. The results show that both AcEW and AlEW have the ability to reduce the Escherichia coli to non-detectable levels (less than 2 log CFU/mL).
Article
In this study, two near neutral pH electrolysed water (NEW1 produced by redirecting of the catholyte solution back to the anode chamber and NEW2 produced by using NaCl and NaHCO3 as electrolyte) and control (NEW0, produced by commercial unit) were evaluated for their stability during 75 h storageat 7°C. The physicochemical properties, bactericidal efficiencies and sanitising effects on organic fresh‐cut lettuce of them were compared.The results showed that NEW2was more stable thanNEW1 and NEW0 during the storage. The free available chlorine of it increased by approximately 35% after the storage.And, all three NEWs showed decreased bactericidal effects compared with that before the storage. In addition, all of them were effective against Escherichia coli and Listeria innocuaSeeliger inoculated on organicfresh‐cut lettuce, with 1.19‐1.40 and 0.92‐1.21 log CFU/greductions, respectively. In terms of physicochemical parameters, there were no significant differences among different treatments.
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Chemical Germicidal Water (CGW) with an effective bactericidal ability was put forward and physicochemical properties, the stability of CGW under different storage conditions, and ultrasonic frequency were investigated. By the aid of plate count method, Escherichia coli was completely inactivated after contacting CGW 10 s, while the bacterial population reduced from 7.6 to 5.29 log CFU/mL by using sodium hypochlorite (NaClO). At the same time, CGW posses lower Minimum Inhibitory Concentration (2 mg/L) and higher bactericidal ability. CGW can reach bacteria killing rate of 97% in a simulation scene room for sterilization, and more than 82% in a dairy processing workshop. Mechanism of action clarified that CGW not only broke the membranes of the bacterium but also destroyed intracellular protein, nucleic acid structures, etc. These results indicate that CGW is an ideal candidate for replacing traditional biocide such as NaClO in the field of food processing industry.
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The use of electrolyzed water in the washing of fruits and vegetables is a promising alternative treatment to chlorine washing. Electrolyzed water washing, is safer, healthier, reduces cleaning times, and is ready to handle. In recent years, food poisoning outbreaks which are caused by bacteria with acid tolerance response in fruits and vegetables has increased. In addition, pathogen produce cases and outbreaks linked to fresh fruits and vegetables, such as cantaloupes, strawberries, fruit salads, spinach, lettuce, celery, and tomatoes has been encountered. Nowadays, the necessity of effective and healthy decontamination processes has gained more importance. The aim of this review is to offer a complete view about electrolyzed water, its classifications and applications. Decontamination results of extant literature of electrolyzed water were also presented. Also, the effects and results of electrolyzed water decontamination on the microbial counts of fresh fruits and vegetables compared with different sanitizing agents have been summarized.
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Listeria monocytogenes, considered as one of the most important foodborne pathogens, is easily found on surfaces, particularly in the form of a biofilm. Biofilms are aggregates of cells that facilitate the persistence of these pathogens in food processing environments conferring resistance to the processes of cleaning and may cause contamination of food during processing, thus, representing a danger to public health. Little is known about the dynamics of the formation and regulation of biofilm production in L. monocytogenes, but several authors reported that the luxS gene may be a precursor in this process. In addition, the product of the inlA gene is responsible for facilitating the entry of the microorganism into epithelial cells that express the receptor E-cadherin, also participates in surface attachment. Thus, 32 strains of L. monocytogenes isolated from different foods (milk and vegetables) and from food processing environments were analyzed for the presence of these genes and their ability to form biofilms on three different surfaces often used in the food industry and retail (polystyrene, glass and stainless steel) at different temperatures (4, 20 and 30 �C). All strains had the ilnA gene and 25 out of 32 strains (78.1%) were positive for the presence of the luxS gene, but all strains produced biofilm in at least one of the temperatures and materials tested. This suggests that genes in addition to luxS may participate in this process, but were not the decisive factors for biofilm formation. The bacteria adhered better to hydrophilic surfaces (stainless steel and glass) than to hydrophobic ones (polystyrene), since at 20 �C for 24 h, 30 (93.8%) and 26 (81.3%) produced biofilm in stainless steel and glass, respectively, and just 2 (6.2%) in polystyrene. The incubation time seemed to be an important factor in the process of biofilm formation, mainly at 35 �C for 48 h, because the results showed a decrease from 30 (93.8%) to 20 (62.5%) and from 27 (84.4%) to 12 (37.5%), on stainless steel and glass, respectively, although this was not significant (p ¼ 0.3847). We conclude that L. monocytogenes is capable of forming biofilm on different surfaces independent of temperature, but the surface composition may be important factor for a faster development of biofilm.
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Listeria monocytogenes, considered as one of the most important foodborne pathogens, is easily found on surfaces, particularly in the form of a biofilm. Biofilms are aggregates of cells that facilitate the persistence of these pathogens in food processing environments conferring resistance to the processes of cleaning and may cause contamination of food during processing, thus, representing a danger to public health. Little is known about the dynamics of the formation and regulation of biofilm production in L. monocytogenes, but several authors reported that the luxS gene may be a precursor in this process. In addition, the product of the inlA gene is responsible for facilitating the entry of the microorganism into epithelial cells that express the receptor E-cadherin, also participates in surface attachment. Thus, 32 strains of L. monocytogenes isolated from different foods (milk and vegetables) and from food processing environments were analyzed for the presence of these genes and their ability to form biofilms on three different surfaces often used in the food industry and retail (polystyrene, glass and stainless steel) at different temperatures (4, 20 and 30 °C). All strains had the ilnA gene and 25 out of 32 strains (78.1%) were positive for the presence of the luxS gene, but all strains produced biofilm in at least one of the temperatures and materials tested. This suggests that genes in addition to luxS may participate in this process, but were not the decisive factors for biofilm formation. The bacteria adhered better to hydrophilic surfaces (stainless steel and glass) than to hydrophobic ones (polystyrene), since at 20 °C for 24 h, 30 (93.8%) and 26 (81.3%) produced biofilm in stainless steel and glass, respectively, and just 2 (6.2%) in polystyrene. The incubation time seemed to be an important factor in the process of biofilm formation, mainly at 35 °C for 48 h, because the results showed a decrease from 30 (93.8%) to 20 (62.5%) and from 27 (84.4%) to 12 (37.5%), on stainless steel and glass, respectively, although this was not significant (p = 0.3847). We conclude that L. monocytogenes is capable of forming biofilm on different surfaces independent of temperature, but the surface composition may be important factor for a faster development of biofilm.
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The presence of Listeria monocytogenes in food processing environment is a risk of food contamination by persistent cells due to their ability to attach to stainless steel and other surfaces. We aimed to study biofilms formation of lux-tagged L. monocytogenes EGDe on stainless steel surfaces and their control using neutral electrolyzed water (NEW), where biofilms development was monitored using destructive and non-destructive microscopy techniques. The development of biofilms was monitored for 5 days on stainless steel chips. We used two sources of NEW, commercial (NEW-1) and from a prototype (NEW-2) for treatments of free and biofilm L. monocytogenes EGDe cells. Complete inhibition of L. monocytogenes EGDe free cells was observed after 1 min contact time for both NEW sources, but NEW-1 concentration used (9 mg/L total available chlorine, TAC) was 1.8 times higher. Cells within biofilms were more resistant to NEW compared to planktonic cells. Same concentration of both NEW sources (70 mg/L TAC) exhibited complete inhibition of biofilm cells after 3 min contact time. However, using a sub-lethal dose of 40 mg/L TAC, NEW-2 reduced about 2 log CFU/cm2 biofilm cells while NEW-1 inhibited 0.3 log CFU/cm2 only. Biofilms formation and antagonistic effect of NEW could be visualized by epifluorescence and scanning electron microscopy, revealing significant biofilms structure. The disinfectant effect of NEW may be attributed to the combined antimicrobial effect of available chlorine and high ORP exhibited by its oxidizing compounds. NEW does not promote metal equipment corrosion due to its neutral pH, and is also environmentally friendly.
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Foodborne illness outbreaks caused by bacterial pathogens may take place on a large scale and result in millions of hospitalizations and thousands of deaths every year throughout the world. One key strategy for dealing with this global issue is the design of smart surfaces and coatings which inhibit and reduce bacterial attachment. This can mitigate contamination and cross-contamination during farm-to-table food processing, promoting food safety, and hygiene. Herein, we reported a durable superhydrophobic coating on aluminum surfaces fabricated by sequential deposition of ultrahard nanodiamond, self-assembly of l-3,4-dihydroxyphenylalanine (l-dopamine), and chemical modification with an organoflurosilane. This coating achieved static, advancing, and receding water contact angles of 159.0±2.5°,154.0±2.4°; and 153.7±1.7°, respectively, representing water super-repellency with a low overall root mean square (rms) roughness of 173.5±69.6 nm. In comparison to the bare, unmodified aluminum, the coated aluminum surfaces prevented the attachment of 99.5% of applied Escherichia coli O157:H7 (E.coli O157:H7) and 99.0% of Staphylococcus aureus (S. aureus) cells. In addition, due to the presence of nanodiamond building blocks, the coated surfaces demonstrated a high mechanical resistance against scratching and endured at least 10,000 shearing/rubbing cycles with a nylon surface. Overall, we anticipate that implementation of this coating could improve safety and hygiene of food-contact surfaces that require harsher mechanical operational conditions.
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Microbial control of postharvest diseases has been extensively studied and appears to be a viable technology. Food safety must be ensured at each postharvest processing step, including handling, washing of raw materials, cleaning of utensils and pipelines, and packaging. Several commercial products are available for this purpose. The time is ripe for developing new techniques and technologies. The use of electrolyzed water (EW) is the product of a new concept developed in Japan, which is now gaining popularity in other countries. Little is known about the principle behind its sterilizing e#ect, but it has been shown to have significant bactericidal and virucidal and moderate fungicidal properties. Some studies have been carried out in Japan, China, and the USA on the pre-and postharvest application of EW in the field of food processing. EW may be produced using common salt and an apparatus connected to a power source. As the size of the machine is quite small, the water can be manufactured on-site. Studies have been carried out on the use of EW as a sanitizer for fruits, utensils, and cutting boards. It can also be used as a fungicide during postharvest processing of fruits and vegetables, and as a sanitizer for washing the carcasses of meat and poultry. It is cost-e#ective and environment-friendly. The use of EW is an emerging technology with considerable potential.
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Ozone, a powerful oxidant, is effective against various kinds of microorganisms on fruits and vegetables. Promising results have been revealed in solving the problems of the food industry like mycotoxin and pesticide residues by ozone application. Spontaneous decomposition without forming hazardous residues in the treatment medium makes ozone safe in food applications. If improperly used, ozone can cause some deleterious effects on products, such as losses in sensory quality. Treatment conditions should be specifically determined for all kinds of products for effective and safe use of ozone.
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Bacteria such as Escherichia coli and Salmonella spp. may cause serious problems for the quality maintenance of pre-packaged lettuces. The aim of this study was to evaluate the bactericidal effect of ozonated water in the washing of iceberg lettuce. For this purpose an ozone generator was integrated into a commercial lettuce-washing facility. Lettuce samples were removed from this process and analysed for mesophilic total viable count (TVC), E. coli, Salmonella spp., vitamin C and sugar content. The analyses were carried out either directly after washing or at the end of best-before date (BBD), in which lettuces were stored at 4 °C for 6 days. Water samples were analysed for total organic carbon (TOC) content and pH. Through the addition of ozone to the wash water the quality of lettuce during storage time was unaffected while there was only a limited observed decrease in populations of microorganisms. Copyright © 2007 Society of Chemical Industry
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The aim of this study was to investigate the effects of the use of chlorine or ozone as sanitizing agents in the water of chicken immersion chilling, using the residual levels usually applied in Brazil (1.5 ppm), comparing the effects of these treatments on the microbiological, physicochemical, and sensory characteristics of carcasses. Chicken carcasses were chilled in water (4°C) with similar residual levels of ozone and chlorine until reaching temperatures below 7°C (around 45 min). The stability of carcasses was assessed during 15 days of storage at 2 ± 1°C. Microbiological, surface color (L*, a*, b* parameters), pH value, lipid oxidation (thiobarbituric acid reactive substances index), and sensory evaluation (on a 9-point hedonic scale for odor and appearance) analyses were carried out. The presence of Salmonella was not detected, coagulase-positive staphylococci counts were below 10(2) CFU/ml of rinse fluid, and Escherichia coli and total coliform counts were below 10(5) CFU/ml of rinse fluid until the end of the storage period for both treatments. Psychrotrophic microorganism counts did not differ (P > 0.05) between chlorine and ozone treatments, and both values were near 10(9) CFU/ml of rinse fluid after 15 days at 4 ± 1°C. pH values did not differ between treatments (P > 0.05) or during the storage period (P > 0.05). In addition, neither chlorine nor ozone treatment showed differences (P > 0.05) in the lipid oxidation of carcasses; however, the thiobarbituric acid reactive substances index of both treatments increased (P ≤ 0.05) during the storage period, reaching values of approximately 0.68 mg of malonaldehyde per kg. Samples from both treatments did not differ (P > 0.05) in their acceptance scores for odor and overall appearance, but in the evaluation of color, ozone showed an acceptance score significantly higher (P ≤ 0.05) than that for the chlorine treatment. In general, under the conditions tested, ozone showed results similar to the results for chlorine in the disinfection of chicken carcasses in the immersion chilling, which may indicate its use as a substitute for chlorine in poultry slaughterhouses.
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The aim of this study was to integrate an ozone-based sanitization step into existing processing practices for fresh produce and to evaluate the efficacy of this step against Escherichia coli O157:H7. Baby spinach inoculated with E. coli O157:H7 (approximately 10(7) CFU/g) was treated in a pilot-scale system with combinations of vacuum cooling and sanitizing levels of ozone gas (SanVac). The contribution of process variables (ozone concentration, pressure, and treatment time) to lethality was investigated using response-surface methodology. SanVac processes decreased E. coli O157:H7 populations by up to 2.4 log CFU/g. An optimized SanVac process that inactivated 1.8 log CFU/g with no apparent damage to the quality of the spinach had the following parameters: O3 at 1.5 g/kg gas-mix (935 ppm, vol/vol), 10 psig of holding pressure, and 30 min of holding time. In a separate set of experiments, refrigerated spinach was treated with low ozone levels (8 to 16 mg/kg; 5 to 10 ppm, vol/vol) for up to 3 days in a system that simulated sanitization during transportation (SanTrans). The treatment decreased E. coli populations by up to 1.4 log CFU/g, and the optimum process resulted in a 1.0-log inactivation with minimal effect on product quality. In a third group of experiments, freshly harvested unprocessed spinach was inoculated with E. coli O157:H7 and sequentially subjected to optimized SanVac and SanTrans processes. This double treatment inactivated 4.1 to > or = 5.0 log CFU/g, depending on the treatment time. These novel sanitization approaches were effective in considerably reducing the E. coli O157: H7 populations on spinach and should be relatively easy to integrate into existing fresh produce processes and practices.
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Biofilms are potential sources of contamination to food in processing plants, because they frequently survive sanitizer treatments during cleaning. The objective of this research was to investigate the combined use of alkaline and acidic electrolyzed (EO) water in the inactivation of Listeria monocytogenes biofilms on stainless steel surfaces. Biofilms were grown on rectangular stainless steel (type 304, no. 4 finish) coupons (2 by 5 cm) in a 1:10 dilution of tryptic soy broth that contained a five-strain mixture of L. monocytogenes for 48 h at 25 degrees C. The coupons with biofilms were then treated with acidic EO water or alkaline EO water or with alkaline EO water followed by acidic EO water produced at 14 and 20 A for 30, 60, and 120 s. Alkaline EO water alone did not produce significant reductions in L. monocytogenes biofilms when compared with the control. Treatment with acidic EO water only for 30 to 120 s, on the other hand, reduced the viable bacterial populations in the biofilms by 4.3 to 5.2 log CFU per coupon, whereas the combined treatment of alkaline EO water followed by acidic EO water produced an additional 0.3- to 1.2-log CFU per coupon reduction. The population of L. monocytogenes reduced by treatments with acidic EO water increased significantly with increasing time of exposure. However, no significant differences occurred between treatments with EO water produced at 14 and 20 A. Results suggest that alkaline and acidic EO water can be used together to achieve a better inactivation of biofilms than when applied individually.
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Disease outbreaks associated with consumption of fresh produce have led to increased demand for technologies that can be used in the home kitchen to decrease pathogen exposure. Produce treatment technologies currently being marketed to consumers include use of electrolyzed oxidizing (EO) water, ozone,and commercial vegetable wash (food-grade soap). In this study, we determined the ability of these technologies.along with chlorine bleach (70 ppm free chlorine) and running tap water, to remove Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica inoculated onto tomatoes.broccoli.cantaloupe, lettuce, spinach, and green onions. Some treatments were more effective than running tap water for specific pathogen-produce combinations, but no treatment produced greater reductions than tap water for all tested combinations. EO water treatment exhibited more consistent effectiveness than the ozone.vegetable wash or tap water and was more effective than chlorine for treating lettuce but less effective than chlorine for treating cantaloupe. The degree of pathogen reduction achieved with the consumer-friendly technologies (1 to 3 log decrease) was similar to reductions achieved in studies using laboratory-generated active agents.
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The main factor contributing to the disinfecting potential of acidic electrolyzed water (AcEW) is deduced to be the oxidizing power of available chlorine. In this study, we compared the reliability of two different methods for measuring the available chlorine concentration (ACC). Several AcEW solutions with different levels of ACC to which various reducing agents (ascorbic acid, ammonium iron (II) sulfate, and iron (II) chloride) had been added were prepared. These ACC levels were quantified by iodometry and the DPD (N, N-diethyl-p-phenylenediamine) method. In the case of AcEW with iron (II) ions, iodometry did not show the correct ACC. On the other hand, the DPD method correctly quantified ACC even in the case of AcEW with iron (II) ions. Thus, the DPD method is an appropriate method for measuring ACC in AcEW. Moreover, we investigated the effect of the available chlorine concentration (ACC) in AcEW on its disinfecting potential. First, we examined the disinfectant effects of AcEW on shredded vegetables. We found that there was no difference in the disinfectant effects between AcEW with high ACC (40 ppm) and low ACC (0.4 ppm). The similar effect was detected in AcEW with 0 ppm of ACC, a solution that seemed to be the same as hydrochloric acid. Moreover, tap water with pH adjusted to 2.4 showed the same disinfectant effect as that of AcEW. These results indicated that AcEW is a solution in which available chlorine is activated in a low pH condition. Next, we examined the disinfectant effects of AcEW on a suspension obtained from shredded vegetables in vitro. The disinfecting potential became weaker, but did not completely disappear, when ACC was reduced to O ppm. Thus, AcEW with low ACC could be used to disinfect shredded vegetables, although the disinfecting potential of AcEW would become weak. When the effective concentration of Ace was examined, it was found that the AcEW with ACC of less than 20 ppm did not have sufficient disinfectant potential. Moreover, it was found that high ORP (above 1000 mV) does not contribute to disinfecting potential. Thus, the lower limit of ACC in AcEW for AcEW to exert a sufficient disinfectant effect will be 20 ppm.
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Present production of wild fish resources is around 85 million tonnes per year, and the maximum long-term potential of marine capture fisheries of some areas and fisheries has been reached. However, not all that is obtained from the sea is adequately used and three clearly differentiated factors can be taken into account to explain this fact: discards, wastage on board and byproducts and wastage ashore. Although some efforts have been made to change this situation, a more efficient and intelligent use is needed of the natural resources extracted from sea and wasted. In this article, the present utilization of discards and fishery wastage and also the future trends and the expected future of fishery industry are presented.
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Acidic electrolyzed water (acidic EW), which is prepared by the electrolysis of an aqueous NaCl solution, has recently become of great importance for disinfection in a variety of fields, including medicine, the food industry and agriculture. In a previous paper we showed that: 1) acidic EW is a mixture of hypocholorite ion, hypochlorous acid and chlorine, depending upon the pH; 2) hypochlorous acid is primarily responsible for disinfection in the case of Escherichia coli K12 and Bacillus subtilis PCI219, both in clean culture media. In practice, however, the use of acidic EW is in many cases severely hampered due to the presence of a variety of non-selective reducing agents. In view of the salient nature of acidic EW, it is therefore strongly urged to establish an optimum way to use acidic EW in a variety of systems. The present paper is the first report on our attempt along this line in order to characterize the nature of the chemical changes that the bactericidal activity of the acidic EW deteriorates in the presence of organic materials, which include amino acids and proteins.
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The current need for minimally-processed foods with fresh-like, natural, and unadulterated qualities has increased the technological search for processes that ensure food safety while maintaining the food in a very wholesome taste-unaltered state. To that end, ozone, supercritical CO2, electrolyzed oxidizing water, and chlorine dioxide were chosen as emerging chemical technologies that hold much potential for ensuring food quality and safety standards. Some of these emerging antimicrobial technologies are briefly described.
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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
The sanitization potency of slightly acidic electrolyzed water (SAEW) on pure cultures of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was evaluated. The potency was compared with that of strong acidic electrolyzed water (StAEW) and sodium hypochlorite (NaOCl) solution. SAEW (ca. pH 5.8 and 21 mg/l available chlorine concentration; ACC) resulted into >5 log10CFU/ml reduction of E. coli and S. aureus after 90 s of exposure. The relative bacterial reduction potency at each exposure time was in the order StAEW > NaOCl > SAEW and increased with exposure time, with relative effect being 90 s > 60 s > 30 s. The results indicate that SAEW with low ACC and near neutral pH can potentially sanitize E. coli and S. aureus within a short period of exposure presenting a potential replacement to NaOCl solution commonly used in the food industry.
Article
Electrolyzed oxidizing (EO) water has been regarded as a new sanitizer in recent years. Production of EO water needs only water and salt (sodium chloride). EO water have the following advantages over other traditional cleaning agents: effective disinfection, easy operation, relatively inexpensive, and environmentally friendly. The main advantage of EO water is its safety. EO water which is also a strong acid, is different to hydrochloric acid or sulfuric acid in that it is not corrosive to skin, mucous membrane, or organic material. Electrolyzed water has been tested and used as a disinfectant in the food industry and other applications. Combination of EO water and other measures are also possible. This review includes a brief overview of issues related to the electrolyzed water and its effective cleaning of food surfaces in food processing plants and the cleaning of animal products and fresh produce.
Article
The Nernst equations between the oxidation-reduction potential (ORP), the concentration of hypochlorous acid and chlorine and the value of pH in electrolyzed oxidizing water (EOW) were developed in three parts, which were in agreement in the measured values. The role of ORP in EOW for killing Escherichia coli O157:H7 was studied. The inactivation effect of EOW on E. coh O157:H7 was also studied by spectroscopy measurements, and the inactivation mechanism was proposed. (c) 2006 Elsevier Ltd. All rights reserved.
Article
Popular foods such as fresh produce and dry nuts are increasingly implicated in outbreaks of food-transmitted diseases. These products are not amenable to conventional processing technologies; therefore, many alternative decontamination methods are actively investigated. Ozone is a versatile sanitizer with promising applications in some high-risk foods. This antimicrobial agent is active against a broad spectrum of microorganisms, and it can be used effectively in its gaseous or aqueous state. The flexibility afforded by ozone use makes it a viable option for application on easy-to-damage products like fresh produce. If process parameters are adequately controlled, ozone treatment can enhance safety and increase shelf life without adversely affecting product quality. Despite these advantages, ozone may not be suitable for some applications, including treatment of liquid foods and products rich in unsaturated fats and soluble proteins. Ozone, as a powerful oxidizer, must be carefully controlled at all times, and equipment must be rigorously maintained to ensure safety of workers.
Article
The effects of different ozone concentrations and ozonation times on the inactivation of Escherichia coli and on the organoleptic properties of whole and ground black peppers were determined. Black peppers were exposed to three different ozone concentrations (0.1, 0.5, and 1.0 ppm) for different periods (0 to 360 min) at 85% +/- 3% relative humidity (RH) and 25 +/- 0.5 degree C. An approximately 7-log CFU/g reduction of E. coli in whole black peppers was achieved by treating the samples with 0.1, 0.5, or 1.0 ppm of ozone for 360, 240, or 120 min, respectively. E. coli populations in ground black peppers were reduced from an initial count of about 7.5 log CFU/g to 1 log CFU/g after 360 min at 0.1- and 0.5-ppm ozone concentrations, whereas the same microbial reduction was obtained after 240 min at 1.0-ppm ozone concentration. An ozone concentration of 0.1 ppm for 360 min was found to be appropriate to inactivate E. coli in whole and ground black peppers without alteration of the organoleptic properties. No significant differences (P > or = 0.05) were present in the bitterness, flavor, odor, color, or overall acceptability values of the whole and ground black peppers treated with 0.1 ppm of ozone for up to 360 min.
Article
This study compared the effectiveness of 10 commercially available sanitizers against Listeria monocytogenes biofilms on high-density polyethylene cutting boards. Smooth and rough surface high-density polyethylene coupons (2 by 5 cm) were inoculated (approximately 6 log CFU/cm2) with a five-strain composite of L. monocytogenes in ham homogenate and incubated at 24 degrees C and > or = 90% relative humidity for up to 21 days. The coupons were subjected to repeated 24-h cycles simulating use and cleaning in the home. Each day, 0.3 ml of a 10-fold-diluted tryptic soy broth containing 0.6% yeast extract was added to each coupon (simulating exposure to nutrients during food preparation), and 8 h later each coupon was rinsed with sterile distilled water. Coupons were subjected to sanitizer treatments on days 0, 0.25, 7, 14, and 21. Eight quaternary ammonium compound (QAC)-based sanitizers, one of lactic acid-based sanitizer, and one sodium hypochlorite-based sanitizer were applied to individual coupons according to the manufacturers' instructions. Coupons were analyzed for L. monocytogenes (PALCAM agar) and total bacteria (tryptic soy agar with 0.6% yeast extract). At 0 and 0.25 days, nine of the sanitizers (all except for QAC-based sanitizer 10) had reduced L. monocytogenes to < 0.60 log CFU/cm2. For > or = 7-day-old biofilms, the lactic acid-based sanitizer (pH 3.03) was the most effective, and the QAC-based sanitizers were more effective when at pH 10.42 to 11.46 than at pH 6.24 to 8.70. Sanitizer efficacies were greater (P < 0.05) against younger (7 days) than older (21 days) biofilms on smooth surfaces. For 7- and 14-day-old biofilms, sanitizer efficacies were higher (P < 0.05) on smooth than on rough surfaces.
Article
To evaluate the efficacy of acidic electrolysed water (EW) in the presence of organic matter (bovine serum) on the inoculated surfaces of lettuce and spinach. Lettuce and spinach leaves were inoculated with a cocktail of three strains each of Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes and treated with deionized water, acidic EW and acidic EW containing bovine serum (5, 10, 15 and 20 ml l(-1)) for 15 s, 30 s, 1 min, 3 min and 5 min at room temperature (22 +/- 2 degrees C). In the absence of bovine serum, acidic EW treatment reduced levels of cells below the detection limit (0.7 log) in 5 min. In the presence of bovine serum, bactericidal activity of acidic EW decreased with increasing serum concentration. Organic matter reduces the effectiveness of acidic EW for reducing pathogens on the surfaces of lettuce and spinach. From a practical standpoint, organic matter reduces the efficacy of acidic EW. This study was conducted to confirm the effect of organic matter on the properties of acidic EW in the inactivation of foodborne pathogens on the surface of vegetables.
Article
Electrolyzed water (EW) is gaining popularity as a sanitizer in the food industries of many countries. By electrolysis, a dilute sodium chloride solution dissociates into acidic electrolyzed water (AEW), which has a pH of 2 to 3, an oxidation-reduction potential of >1,100 mV, and an active chlorine content of 10 to 90 ppm, and basic electrolyzed water (BEW), which has a pH of 10 to 13 and an oxidation-reduction potential of -800 to -900 mV. Vegetative cells of various bacteria in suspension were generally reduced by > 6.0 log CFU/ml when AEW was used. However, AEW is a less effective bactericide on utensils, surfaces, and food products because of factors such as surface type and the presence of organic matter. Reductions of bacteria on surfaces and utensils or vegetables and fruits mainly ranged from about 2.0 to 6.0 or 1.0 to 3.5 orders of magnitude, respectively. Higher reductions were obtained for tomatoes. For chicken carcasses, pork, and fish, reductions ranged from about 0.8 to 3.0, 1.0 to 1.8, and 0.4 to 2.8 orders of magnitude, respectively. Considerable reductions were achieved with AEW on eggs. On some food commodities, treatment with BEW followed by AEW produced higher reductions than did treatment with AEW only. EW technology deserves consideration when discussing industrial sanitization of equipment and decontamination of food products. Nevertheless, decontamination treatments for food products always should be considered part of an integral food safety system. Such treatments cannot replace strict adherence to good manufacturing and hygiene practices.
Article
Electrolyzed strong acid water (ESW) containing free chlorine at various concentrations is becoming to be available in clinical settings as a disinfectant. ESW is prepared by electrolysis of a NaCl solution, and has a corrosive activity against medical instruments. Although lower concentrations of NaCl and free chlorine are desired to eliminate corrosion, the germicidal effect of ESW with low NaCl and free-chlorine concentrations (ESW-L) has not been fully clarified. In this study, we demonstrated that ESW-L possesses bactericidal activity against Mycobacteria and spores of Bacillus subtilis. The effect was slightly weaker than that of ESW containing higher NaCl and free-chlorine concentrations (ESW-H), but acceptable as a disinfectant. To clarify the mechanism of the bactericidal activity, we investigated ESW-L-treated Pseudomonas aeruginosa by transmission electron microscopy, a bacterial enzyme assay and restriction fragment length polymorphism pattern (RFLP) assay. Since the bacterium, whose growth was completely inhibited by ESW-L, revealed the inactivation of cytoplasmic enzyme, blebs and breaks in its outer membrane and remained complete RFLP of DNA, damage of the outer membrane and inactivation of cytoplasmic enzyme are the important determinants of the bactericidal activity.
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
Epidemiological data from Europe, North America, Australia, and New Zealand indicate that a substantial proportion of foodborne disease is attributable to improper food preparation practices in consumers' homes. International concern about consumer food safety has prompted considerable research to evaluate domestic food-handling practices. The majority of consumer food safety studies in the last decade have been conducted in the United Kingdom and Northern Ireland (48%) and in the United States (42%). Surveys (questionnaires and interviews), the most frequent means of data collection, were used in 75% of the reviewed studies. Focus groups and observational studies have also been used. One consumer food safety study examined the relationship between pathogenic microbial contamination from raw chicken and observed food-handling behaviors, and the results of this study indicated extensive Campylobacter cross-contamination during food preparation sessions. Limited information about consumers' attitudes and intentions with regard to safe food-handling behaviors has been obtained, although a substantial amount of information about consumer knowledge and self-reported practices is available. Observation studies suggest that substantial numbers of consumers frequently implement unsafe food-handling practices. Knowledge, attitudes, intentions, and self-reported practices did not correspond to observed behaviors, suggesting that observational studies provide a more realistic indication of the food hygiene actions actually used in domestic food preparation. An improvement in consumer food-handling behavior is likely to reduce the risk and incidence of foodborne disease. The need for the development and implementation of food safety education strategies to improve specific food safety behaviors is reviewed in this paper.
Article
Studies have demonstrated that electrolyzed oxidizing (EO) water is effective in reducing foodborne pathogens on fresh produce. This study was undertaken to determine the efficacy of EO water and two different forms of chlorinated water (chlorine water from Cl2 and Ca(OCl)2 as sources of chlorine) in inactivating Salmonella on alfalfa seeds and sprouts. Tengram sets of alfalfa seeds inoculated with a five-strain cocktail of Salmonella (6.3 x 10(4) CFU/g) were subjected to 90 ml of deionized water (control), EO water (84 mg/liter of active chlorine), chlorine water (84 mg/liter of active chlorine), and Ca(OCl)2 solutions at 90 and 20,000 mg/liter of active chlorine for 10 min at 24 +/- 2 degrees C. The application of EO water, chlorinated water, and 90 mg/liter of Ca(OCl)2 to alfalfa seeds for 10 min reduced initial populations of Salmonella by at least 1.5 log10 CFU/g. For seed sprouting, alfalfa seeds were soaked in the different treatment solutions described above for 3 h. Ca(OCl)2 (20,000 mg/liter of active chlorine) was the most effective treatment in reducing the populations of Salmonella and non-Salmonella microflora (4.6 and 7.0 log10 CFU/g, respectively). However, the use of high concentrations of chlorine generates worker safety concerns. Also, the Ca(OCl)2 treatment significantly reduced seed germination rates (70% versus 90 to 96%). For alfalfa sprouts, higher bacterial populations were recovered from treated sprouts containing seed coats than from sprouts with seed coats removed. The effectiveness of EO water improved when soaking treatments were applied to sprouts in conjunction with sonication and seed coat removal. The combined treatment achieved 2.3- and 1.5-log10 CFU/g greater reductions than EO water alone in populations of Salmonella and non-Salmonella microflora, respectively. This combination treatment resulted in a 3.3-log10 CFU/g greater reduction in Salmonella populations than the control (deionized water) treatment.
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
The effects of chlorine and pH on the bactericidal activity of electrolyzed (EO) water were examined against Escherichia coli O157:H7 and Listeria monocytogenes. The residual chlorine concentration of EO water ranged from 0.1 to 5.0 mg/l, and the pH effect was examined at pH 3.0, 5.0, and 7.0. The bactericidal activity of EO water increased with residual chlorine concentration for both pathogens, and complete inactivation was achieved at residual chlorine levels equal to or higher than 1.0 mg/l. The results showed that both pathogens are very sensitive to chlorine, and residual chlorine level of EO water should be maintained at 1.0 mg/l or higher for practical applications. For each residual chlorine level, bactericidal activity of EO water increased with decreasing pH for both pathogens. However, with sufficient residual chlorine (greater than 2 mg/l), EO water can be applied in a pH range between 2.6 (original pH of EO water) and 7.0 while still achieving complete inactivation of E. coli O157:H7 and L. monocytogenes.
Article
To evaluate the efficacy of electrolysed NaCl solutions (EW) for disinfecting bacterial isolates from carp, and the potential application of EW to reducing the bacterial load in whole carp and carp fillets. EW was produced by using a two-compartment batch-type electrolysed apparatus. Pure cultures (in vitro), whole carp (skin surface) and carp fillets were treated with EW to detect its antimicrobial effects. The anodic solution [EW (+)] completely inhibited growth of the isolates. Furthermore, dipping the fish samples in EW (+) reduced the mean total count of aerobic bacteria on the skin of whole carp and in fillets by 2.8 and 2.0 log(10), respectively. The cathodic solution [EW (-)] also reduced growth of the isolates from carp by ca 1.0 log(10). Moreover, the total counts of aerobic bacteria in whole carp (on the skin) and fillets were reduced by 1.28 and 0.82 log(10), respectively. EW (+) has a strong bactericidal effect on bacteria isolated from carp. Treatment with EW (+) could extend the shelf life of these fish.
Article
To ascertain the efficacy of neutral electrolysed water (NEW) in reducing Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes on glass and stainless steel surfaces. Its effectiveness for that purpose is compared with that of a sodium hypochlorite (NaClO) solution with similar pH, oxidation-reduction potential (ORP) and active chlorine content. First, the bactericidal activity of NEW was evaluated over pure cultures (8.5 log CFU ml-1) of the abovementioned strains: all of them were reduced by more than 7 log CFU ml-1 within 5 min of exposure either to NEW (63 mg l-1 active chlorine) or to NaClO solution (62 mg l-1 active chlorine). Then, stainless steel and glass surfaces were inoculated with the same strains and rinsed for 1 min in either NEW, NaClO solution or deionized water (control). In the first two cases, the populations of all the strains decreased by more than 6 log CFU 50 cm-2. No significant difference (P<or=0.05) was found between the final populations of each strain with regard to the treatment solutions (NEW or NaClO solution) or to the type of surface. NEW was revealed to be as effective as NaClO at significantly reducing the presence of pathogenic and spoilage bacteria (in this study, E. coli, L. monocytogenes, P. aeruginosa and S. aureus) on stainless steel and glass surfaces. NEW has the advantage of being safer than NaClO and easier to handle. Hence, it represents an advantageous alternative for the disinfection of surfaces in the food industry.
Article
The effects of electrolyzed oxidizing (EO) water on reducing Listeria monocytogenes contamination on seafood processing surfaces were studied. Chips (5 x 5 cm(2)) of stainless steel sheet (SS), ceramic tile (CT), and floor tile (FT) with and without crabmeat residue on the surface were inoculated with L. monocytogenes and soaked in tap or EO water for 5 min. Viable cells of L. monocytogenes were detected on all chip surfaces with or without crabmeat residue after being held at room temperature for 1 h. Soaking contaminated chips in tap water resulted in small-degree reductions of the organism (0.40-0.66 log cfu/chip on clean surfaces and 0.78-1.33 log cfu/chip on dirty surfaces). Treatments of EO water significantly (p<0.05) reduced L. monocytogenes on clean surfaces (3.73 log on SS, 4.24 log on CT, and 5.12 log on FT). Presence of crabmeat residue on chip surfaces reduced the effectiveness of EO water on inactivating Listeria cells. However, treatments of EO water also resulted in significant reductions of L. monocytogenes on dirty surfaces (2.33 log on SS and CT and 1.52 log on FT) when compared with tap water treatments. The antimicrobial activity of EO water was positively correlated with its chlorine content. High oxidation-reduction potential (ORP) of EO water also contributed significantly to its antimicrobial activity against L. monocytogenes. EO water was more effective than chlorine water on inactivating L. monocytogenes on surfaces and could be used as a chlorine alternative for sanitation purpose. Application of EO water following a thorough cleaning process could greatly reduce L. monocytogenes contamination in seafood processing environments.
Article
Food processing gloves are typically used to prevent cross-contamination during food preparation. However, gloves can be contaminated with microorganisms and become a source of contamination. This study investigated the survival of Listeria monocytogenes on gloves and determined the efficacy of electrolyzed oxidizing (EO) water for reducing L. monocytogenes contamination on seafood processing gloves. Three types of reusable gloves (natural rubber latex, natural latex, and nitrile) and two types of disposable gloves (latex and nitrile) were cut into small pieces (4 x 4 cm(2)) and inoculated with 5-strain L. monocytogenes cocktail (5.1 x 10(7) CFU/cm(2)) with and without shrimp meat residue attached to surfaces. L. monocytogenes did not survive well on clean reusable gloves and its populations decreased rapidly to non-detectable levels within 30 min at room temperature. However, high levels of Listeria cells were recovered from clean disposable gloves after 30 min of inoculation. Presence of shrimp meat residue on gloves enhanced the survival of L. monocytogenes. Cells of L. monocytogenes were detected on both reusable and disposal gloves even after 2 h at room temperature. Soaking inoculated gloves in EO water at room temperature for 5 min completely eliminated L. monocytogenes on clean gloves (>4.46 log CFU/cm(2) reductions) and significantly (p<0.05) reduced the contamination on soil-containing gloves when compared with tap water treatment. EO water could be used as a sanitizer to reduce L. monocytogenes contamination on gloves and reduce the possibility of transferring L. monocytogenes from gloves to RTE seafoods.
Article
The ability of electrolyzed (EO) water to inactivate Listeria monocytogenes in suspension and biofilms on stainless steel in the presence of organic matter (sterile filtered chicken serum) was investigated. A five-strain mixture of L. monocytogenes was treated with deionized, alkaline EO, and acidic EO water containing chicken serum (0, 5, and 10 ml/liter) for 1 and 5 min. Coupons containing L. monocytogenes biofilms were also overlaid with chicken serum (0, 2.5, 5.0, and 7.5 ml/liter) and then treated with deionized water, alkaline EO water, acidic EO water, alkaline EO water followed by acidic EO water, and a sodium hypochlorite solution for 30 and 60 s. Chicken serum decreased the oxidation-reduction potential and chlorine concentration of acidic EO water but did not significantly affect its pH. In the absence of serum, acidic EO water containing chlorine at a concentration of 44 mg/liter produced a > 6-log reduction in L. monocytogenes in suspension, but its bactericidal activity decreased with increasing serum concentration. Acidic EO water and acidified sodium hypochlorite solution inactivated L. monocytogenes biofilms to similar levels, and their bactericidal effect decreased with increasing serum concentration and increased with increasing time of exposure. The sequential 30-s treatment of alkaline EO water followed by acidic EO water produced 4- to 5-log reductions in L. monocytogenes biofilms, even in the presence of organic matter.
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
Food safety issues and increases in food borne illnesses have promulgated the development of new sanitation methods to eliminate pathogenic organisms on foods and surfaces in food service areas. Electrolyzed oxidizing water (EO water) shows promise as an environmentally friendly broad spectrum microbial decontamination agent. EO water is generated by the passage of a dilute salt solution ( approximately 1% NaCl) through an electrochemical cell. This electrolytic process converts chloride ions and water molecules into chlorine oxidants (Cl(2), HOCl/ClO(-)). At a near-neutral pH (pH 6.3-6.5), the predominant chemical species is the highly biocidal hypochlorous acid species (HOCl) with the oxidation reduction potential (ORP) of the solution ranging from 800 to 900mV. The biocidal activity of near-neutral EO water was evaluated at 25 degrees C using pure cultures of Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis. Treatment of these organisms, in pure culture, with EO water at concentrations of 20, 50, 100, and 120ppm total residual chlorine (TRC) and 10min of contact time resulted in 100% inactivation of all five organisms (reduction of 6.1-6.7log(10)CFU/mL). Spray treatment of surfaces in food service areas with EO water containing 278-310ppm TRC (pH 6.38) resulted in a 79-100% reduction of microbial growth. Dip (10min) treatment of spinach at 100 and 120ppm TRC resulted in a 4.0-5.0log(10)CFU/mL reduction of bacterial counts for all organisms tested. Dipping (10min) of lettuce at 100 and 120ppm TRC reduced bacterial counts of E. coli by 0.24-0.25log(10)CFU/mL and reduced all other organisms by 2.43-3.81log(10)CFU/mL.
Article
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.
The efficiency of disinfection of acidic electrolyzed water in the presence of organic materials Table 6 Survival of Listeria monocytogenes dried on coupons after treatment with antimicrobial water treatments (log CFU/coupon)a
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Use of ozone in a lettuce-washing process: an industrial trial Electrolyzed water and its application in the food industry Application of electrolyzed water in the food industry
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Applications of electrolyzed water in agriculture & food industries
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