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Effectiveness of low concentration electrolyzed water to inactivate foodborne pathogens under different environmental conditions
... Although several disinfectants have been extensively used, constraints such as chemical residues, low efficiency, cost, and impact on the environment have been cited [1]. Electrolyzed water (EW) is widely accepted as a practical disinfectant because it does not make use of hazardous chemical substances and processes [2]. Studies have shown that EW has gained immense popularity because of its ease of production and application; therefore, it has been extensively applied in food sanitization [1][2][3][4][5][6][7][8][9][10], environmental sanitization [11], livestock farming [12][13][14][15][16][17][18], and medical sterilization [19][20][21][22][23]. ...
... Electrolyzed water (EW) is widely accepted as a practical disinfectant because it does not make use of hazardous chemical substances and processes [2]. Studies have shown that EW has gained immense popularity because of its ease of production and application; therefore, it has been extensively applied in food sanitization [1][2][3][4][5][6][7][8][9][10], environmental sanitization [11], livestock farming [12][13][14][15][16][17][18], and medical sterilization [19][20][21][22][23]. ...
... HOCl works by penetrating the germ cell membrane and generates hydroxyl radicals, destroying the pathogen through oxidation [112]. Rahman et al. [2] found that the antimicrobial efficacy of EW was diminished at pH 9.0, because the ORP and ACC decreased significantly with an increase in pH from the acidic region of 2.5 to the basic region of 9.0. Park et al. [115] investigated the effect of ACC and pH of AEW on the inactivation of L. monocytogenes and E. coli. ...
Currently, electrolyzed water, a sustainable and environmentally friendly disinfectant produced through electrolysis of an acid or salt, has become very popular because of its applications in various sectors such as health, agriculture, and food. Influencing factors are important for optimizing the electrolyzed water production process and maximizing application efficiency. Factors that influence the production and efficiency of electrolyzed water, including water and electrolyte properties, electrode material, current, storage, and application factors, were reviewed in this study. Moreover, some commercially available generator models, their specifications, and issues are discussed along with future recommendations. This work summarizes the available literature from January 2000 to December 2020, reporting studies that can assist in understanding various parameters affecting the production and stability of electrolyzed water. This can provide further insights and aid researchers in optimizing the process and address the issues faced by the existing systems by offering new perspectives in future studies.
... EW has three main physical properties-the available chlorine concentration (ACC), the pH value and the oxidation-reduction potential (ORP)-and the difference in these properties will load the EW into different sterilization effects. Numerous studies have shown the interaction effects among these factors [23,24]. According to the different devices, electrolyte and electrolysis conditions, EW can be classified into the following categories: AEW, WAEW, NEW and BEW. ...
... When the pH of the solution is 5.0 to 6.5, the primary chlorine is in the form of HOCl, and its disinfection ability is 80 times that of -OCl [34]. The results show that the ORP and ACC of EW decreased significantly when the pH increased from acid (pH 2.5) to alkaline (pH 9.0) [23]. In addition, EW generated at different temperatures shows different ACC [35]. ...
... In addition, EW generated at different temperatures shows different ACC [35]. ACC can be reduced with the increasing storage time [23]. On the other hand, free radicals (such as hydroxyl radicals (OH·)) are also considered to be bactericidal components of EW [36]. ...
Electrolyzed water (EW) is a new type of cleaning and disinfecting agent obtained by means of electrolysis with a dilute sodium chloride solution. It has low cost and harm to the human body and is also friendly to the environment. The anode produces acidic electrolyzed water (AEW), which is mainly used to inhibit bacterial growth and disinfect. The cathode provides basic electro-lyzed water (BEW), which is implemented to promote human health. EW is a powerful multifunc-tional antibacterial agent with a wide range of applications in the medicine, agriculture, and food industry. Studies in vitro and in vivo show that it has an inhibitory effect on pathogenic bacteria and viruses. Therefore, EW is used to prevent chronic diseases, while it has been found to be effective against various kinds of infectious viruses. Animal experiments and clinical trials clearly showed that it accelerates wound healing, and has positive effects in oral health care, anti-obesity, lowering blood sugar, anti-cancer and anti-infectious viral diseases. This review article summarizes the application of EW in treating bacteria and viruses, the prevention of chronic diseases, and health promotion.
... The ACC concentrations of both NEW and SAEW were adjusted to 50, 100, 150 and 200 mg/L by diluting with sterile deionized water (DW). The pH of the electrolyzed water was adjusted to 5.0 and 7.0 for simulating SAEW and NEW, respectively, by using HCl and NaOH solutions at 0.1 N (Rahman et al., 2010). The ACC, pH and ORP were determined for all solutions. ...
... Researchers have reported that EW with pH ranging from 5.0 to 6.5 and 7.0-8.0 presented ORP ranging around 950 mV and 750-900 mV, respectively, which is in accordance with the present study (Issa-Zacharia et al., 2011;Rahman et al., 2010Rahman et al., , 2016. ...
... Maximum reductions of L. monocytogenes on stainless steel surfaces were higher after treatments with SAEW in comparison with treatments with NEW (P ≤ 0.05) ( Table 1). The effective form of the chlorine in EW with pH ranging from 5.0 to 6.5 is mainly hypochlorous acid (HOCl) (Rahman et al., 2010). By decreasing the pH of electrolyzed water, the bacterial cells become more vulnerable to chlorine, as their external layer becomes more susceptible to HOCl infiltration (Park et al., 2004;Rahman et al., 2016). ...
The efficacy of electrolyzed water (EW) to inactivate Listeria monocytogenes on stainless steel surfaces was evaluated and modelled in the present study. L. monocytogenes was inoculated on stainless steel coupons and subsequently subjected to Neutral EW (NEW, pH = 7.0) and Slightly Acid EW (SAEW, pH = 5.0) with different Available Chlorine Concentration (ACC, 50–200 mg/L) for different exposure times (0–6 min). The number of viable cells on coupons decreased as the exposure time increased at all ACC concentrations. Treatments with SAEW resulted in higher reductions of L. monocytogenes, i.e., 2.30 ± 0.16 to 5.64 ± 0.11 log cfu/cm², in comparison with NEW treatments (1.55 ± 0.11 to 5.22 ± 0.12 log cfu/cm²), probably due to the synergistic bactericidal effect between the acidic pH, higher oxidation-reduction potential and the effective form of chlorine, reported in previous studies. Since SAEW was the most effective against L. monocytogenes, two approaches were tested to model the survival data: the one- and two-step modelling procedures. The Weibull model was suitable to describe the survival data and both approaches produced suitable survival models (adj-R²>0.92 and MSE<0.2). EW is effective in reducing bacterial contamination in food-contact surfaces and the survival data and models derived from this study are relevant to optimize its use as an environment-friendly sanitizer in the food industry.
... Although having potential antimicrobial activity, AEW has a relatively low pH of 2-3 at which Cl 2 is easy to volatilize into the air which consequently poses threat to health. Moreover, AEW may be corrosive to organic materials due to its high acidity, which ultimately limits its application (Rahman et al. 2010a(Rahman et al. , b, c, 2012. On the contrary, the acidity of SAEW is slighter (pH 5.0-6.5) and it has an ORP no more than 1000 mV and ACC with the range from 10 to 30 mg/L while its bactericidal capacity is pretty strong on account of HClO as the main form of available chlorine (Ding et al. 2016;. ...
... However, the potential application of AEW is limited because of its low pH (2.2-2.7). The electrolyzed water with high acidity could be corrosive to the metal equipment, and the free chlorine (Cl 2 ) in this product could cause cytotoxicity and genotoxicity (Rahman et al. 2010a). SAEW is a newly developed sanitizer that has proven promising and safe in several previous studies. ...
Foods of animal origin, such as red meat and poultry products, are primary sources of superior protein for humans. With the production and consumption of these products increasing rapidly in recent decades, microbial safety and food quality are vital issues. Electrolyzed water (EW) as a sanitizer has awakened high interest in the food industry of many countries. The use of EW to decontaminate fresh red meat, ready-to-eat meat, poultry and shell eggs has been effective in reducing pathogenic microorganisms. Moreover, EW presents many advantages over traditional decontaminants; it provides effective antimicrobial activity and is environmentally friendly, simple to handle and relatively inexpensive. However, no complete elimination of pathogens on red meat and chicken meat was obtained after treatment of the meats with EW. This result probably occurs because organic matter and blood residue were present. This chapter provides a brief overview of how EW treatment affects foods of animal origin, especially the microbial safety and the physicochemical and sensory qualities of the food.
... El agua electrolizada acida tiene un fuerte efecto antimicrobiano debido a su bajo pH (2-4), alto potencial oxido reducción y a sus activos oxidantes como el ácido hipocloroso. No obstante, presenta algunas desventajas, es potencial mente corrosiva para los equipos utilizados en los procesos e irritante para las manos, y presenta una vida corta de almacén debido a la pérdida de cloro, ya que a este pH bajo, el Cl2 disuelto en gas puede rápidamente perderse por efecto de la volatilización, pudiendo afectar de manera adversa la salud humana y medioambiente (Abadias et al., 2008;Guentzel et al., 2008;Rahman et al., 2010;Wang et al., 2016). ...
... Acid electrolyzed water has a strong antimicrobial effect due to its low pH (2-4), high potential oxidation reduction and its oxidizing actives such as hypochlorous acid. However, it has some disadvantages, is potentially corrosive to the equipment used in the processes and irritant to the hands, and presents a short shelf life due to the loss of chlorine, since at this low pH, the Cl2 dissolved in gas can rapidly be lost as a result of volatilization, and may adversely affect human health and the environment (Abadias et al., 2008;Guentzel et al., 2008;Rahman et al., 2010;Wang et al., 2016). ...
Neutral electrolysed water (NEW) is a novel antimicrobial agent, which has an effect on a large variety of microorganisms, safe for humans and the environment. The efficiency of NEW in the reduction of spore germination and development of the germinative tube in fungi of postharvest importance was determined. A suspension of 8 × 107 mL-1
spores of the fungi Botrytis cinerea isolated from blackberry, Colletotrichum gloeosporioides isolated from mango, guava and lychee, Fusarium solani isolated from chili and stevia, Monilinia fructicola isolated from peach, Penicillium digitatum isolated from Mexican lemon and Persian lemon, Penicillium sp., papaya isolate and Rhizopus stolonifer isolated from yaca and soursop, were in contact with NEW for 5 min at concentrations of 3, 5, 6, 8, 18, 24, 27, 29, 36 and 43 ppm free chlorine, and sterile distilled water (control). Spores were seeded in culture medium potato
dextrose agar (Bioxon®); the evaluations were carried out at 24 and 48 hours after sowing. The 100% inhibition of spore germination and Botrytis germ length was observed in the concentration range of 18-43 ppm, Colletotrichum (6-43 ppm), Fusarium (6-43 ppm), Monilinia (8 and 24-43 ppm), Penicillium (18-43 ppm), Rhizopus isolated from soursop (5-24 and 29-43 ppm) and Rhizopus of yaca (18-43 ppm). The results suggest that NEW could be used as an alternative control of post-harvest fungi.
... Studies investigating EOW treatment of aqueous human pathogen suspensions under varying conditions of exposure time, pH, temperature, available chlorine, and redox potential have consistently shown substantial log reductions in viable microorganisms [13][14][15][16] . Of the various types of EOW, neutral EOW has been considered the ...
... The efficacy of EOW at pH 9.2 was somehow unexpected, as Pangloli and Hung 33 found that the bactericidal efficacy of EOW against E. coli O157:H7 at pH values in the range of 5-8 was unaffected, but that there was a significant decrease in efficacy at pH 8 against L. monocytogenes. Similarly, Rahman et al. 15 found that the ability of EOW to inactivate all organisms was diminished at pH 9.0. It is unclear which factors contributed to the high activity of the neutral EOW used in this study at high pH. ...
There is increasing demand for safe and effective sanitizers for irrigation water disinfection to prevent transmission of foodborne pathogens to fresh produce. Here we compared the efficacy of pH-neutral electrolyzed oxidizing water (EOW), sodium hypochlorite (NaClO) and chlorine dioxide (ClO2) against single and mixed populations of E. coli, Listeria and Salmonella under a range of pH and organic matter content. EOW treatment of the mixed bacterial suspension resulted in a dose-dependent (<1 mg/L free chlorine), rapid (<2 min) and effective (4–6 Log10) reduction of the microbial load in water devoid of organic matter under the range of pH conditions tested (pH, 6.0, 7.0, 8.4 and 9.2). The efficacy of EOW containing 5 mg/L free chlorine was unaffected by increasing organic matter, and compared favourably with equivalent concentrations of NaClO and ClO2. EOW at 20 mg/L free chlorine was more effective than NaClO and ClO2 in reducing bacterial populations in the presence of high (20–100 mg/L) dissolved organic carbon, and no regrowth or metabolic activity was observed for EOW-treated bacteria at this concentration upon reculturing in rich media. Thus, EOW is as effective or more effective than other common chlorine-based sanitizers for pathogen reduction in contaminated water. EOW’s other characteristics, such as neutral pH and ease of handling, indicate its suitability for fresh produce sanitation.
... It has a pH of 6.0-6.5, OPR as 500-520 mV and ACC less than 10 ppm. Its low concentration of chlorine and relative neutral pH may cause less erosion and negative effect on environment [14] , [25] , [26]. ...
... Meat safety is another arising issue in food industry hence Han and others studied the antimicrobial efficacy of NEW on pork products and pure cultures, in addition, they observe the formation of viable but nonculturable cells (VBNC) after treatments. Application of NEW (pH, 7.64 ± 0.07; ORP, 818 ± 5.57 mV; ACC 37 ppm) for S. enteritidis [14] resulted in complete inactivation of S. enteritidis and no VBNC cells were detected. Inoculated pork chops and skin samples were treated with 100% NEW (ACC 74 ppm) for 2 or 10 mins. ...
Uncontrolled growth of microorganism in foodstuff pose a severe challenge to the food industry, as it could leads to food spoilage, or even foodborne disease if the microorganism is pathogenic. To deal with these threats, sanitizers has been widely applied widely by food industry. In the last two decades, electrolyzed water (EW) has been food to be a promising new sanitizer for food industry, as it is more environmentally friendly compared to conventional chlorine-based disinfectants. This paper reviews the recent progress on the application of EW as a food sanitizer. EW was produced by the electrolysis of diluted NaCl (or HCl) solution and could be classified into several subgroups (acid EW, slightly EW, neutral EW, alkaline EW, low concentration) based on their pH and available chlorine concentration. The efficacy of using EW to inhibit the growth of several most important microorganism of food safety concern were proven by numerous studies. Besides, the application of EW has been seldomly associated with detrimental effects on the nutritional and sensory proprieties of food. However, its antimicrobial potency was affected by factors such as pH, temperature, storage time, and organic matter.
... Despite having AEW's antibacterial capability, it has a little pH of below 3 to make Cl 2 volatilize into the air easily, tending to a health risk. Furthermore, because of its high acidity, AEW is likely to be corrosive to organic materials, narrowing its applicability (Rahman et al., 2012;Rahman et al., 2010a;Rahman et al., 2010b;Rahman, Jin, & Oh, 2010). SAEW, on the contrary, has gotten a lot of interest because it has a lot of antibacterial action, does not corrode processing equipment, and shows comparatively less harmful effects on the environment and human health (Ding et al., 2015;Hao et al., 2015a). ...
Fruits and vegetables deteriorate mostly due to microbial and enzymatic activity during
postharvest storage. The objective of the work was to see if electrolyzed water and ultrasound can be applied combinedly in the industry to extend the shelf life of harvested fruits and vegetables. Ultrasound is a novel postharvest treatment method that has the potential to inactivate enzymes and microbes. Pectinmethylesterase, polygalacturonase, peroxidase, polyphenoloxidase, and lipoxygenase are the enzymes that are most commonly deactivated by ultrasound in fruits and vegetables. On the contrary, electrolyzed water is a potential antibacterial agent for fresh fruits and vegetables. Electrolyzed water treatment has some limitations in terms of microbial load reduction, which can be solved using sonication. This article deeply looked into the principles, advantages, disadvantages, and mechanism of action of both techniques.
Novelty impact statement: Individual and synergistic effects on shelf life extension of fruits and vegetables were reviewed. In addition, the inactivation mechanisms of microorganisms and enzymes of fruits and vegetables have been explained.
... Alkaline ionized water (AEW) obtained by the water electrolysis is considered akin to a dilute sodium hydroxide produced in the cathode compartment (Koseki, Yoshida, Isobe, & Itoh, 2001). Its antioxidative effects were reported on the highly unsaturated fats and oils (Miyashita, Yasuda, Ota, & Suzuki, 1999), the microbial inactivation (Bari, Sabina, Isobe, Uemura, & Isshiki, 2003), lettuce (Koseki, Isobe, & Itoh, 2004), the disinfection of apples (Graca, Abadias, Salazar, & Nunes, 2011), and the inactivation of foodborne pathogens (Rahman et al., 2010a(Rahman et al., , 2010bRahman, Park, Wang, & Oh, 2012). Also, its combination with ozone and UV-C achieved the shelf life extension (Jemni et al., 2014). ...
The study aimed at thesurface disinfection and shelf life extension ofcherry tomatoesusingozone (1O3;17.2 g/m3 ozone for 4 min and 2O3;17.2 g/m3 ozone for 12 min),alkaline ionized water (1AEW; pH 10 for 20 min and 2AEW; pH 8.5 for 20 min), and theireight combinations. No significant difference was detected inL*, a*, b*, chroma, hue,and browning index; and titratable acidity,chroma, hue, total antioxidant capacity,and total phenolic and lycopene contents.All the treatments significantly reducedtotal aerobic mesophilic bacteria, mold and yeast counts and inoculated SalmonellaEnteritidis,Listeriamonocytogenes and Botyritiscinerea.1AEW+2O3led toa shelf life of seven weeks, whereas the other treatments and control groups had a shelf life of five and threeweeks, respectively.The joint optimization pointed to 2O3+1AEW, 2O3+2AEW, and 2AEW+1O3 as the optimal treatments.
... Despite having AEW's antibacterial capability, it has a little pH of below 3 to make Cl 2 volatilize into the air easily, tending to a health risk. Furthermore, because of its high acidity, AEW is likely to be corrosive to organic materials, narrowing its applicability (Rahman et al., 2012;Rahman et al., 2010a;Rahman et al., 2010b;Rahman, Jin, & Oh, 2010). SAEW, on the contrary, has gotten a lot of interest because it has a lot of antibacterial action, does not corrode processing equipment, and shows comparatively less harmful effects on the environment and human health (Ding et al., 2015;Hao et al., 2015a). ...
Fruits and vegetables deteriorate mostly due to microbial and enzymatic activity during postharvest storage. The objective of the work was to see if electrolyzed water and ultrasound can be applied combinedly in the industry to extend the shelf life of harvested fruits and vegetables. Ultrasound is a novel postharvest treatment method that has the potential to inactivate enzymes and microbes. Pectinmethylesterase, polygalacturonase, peroxidase, polyphenoloxidase, and lipoxygenase are the enzymes that are most commonly deactivated by ultrasound in fruits and vegetables. On the other hand, electrolyzed water is a potential antibacterial agent for fresh fruits and vegetables. Electrolyzed water treatment has some limitations in terms of microbial load reduction, which can be solved using sonication. This article deeply looked into the principles, advantages, disadvantages, and mechanism of action of both techniques.
... The antimicrobial mechanisms of AEW could be mainly attributed to three factors, free available chlorine (FAC), oxidation reduction potential (ORP) and pH (Hati et al., 2012). There exist interaction effects among them, for example, the FAC and ORP values were found to decrease significantly when the pH increased (Rahman, Ding, & Oh, 2010). Besides, high ORP played an important role in the bactericidal effects of AEW, as it could damage cell membrane and increase membrane penetrability to make intracellular components released, leading to necrosis of bacteria (Liao, Chen, & Xiao, 2007). ...
Thesanitisingeffectoflowconcentrationacidicelectrolysedwater(AEW,freeavailablechlorine(FAC):4mg/L) combined with levulinic acid (LA, 3% v/v) on fresh organic lettuce during 7-day storage was evaluated. The combinedsanitisingmethodshowedadditionalbactericidalefficacyagainstnaturallyexistingmicrobiota, while LAaloneandcombinedwithAEWcouldreducesurvivalpopulationofEscherichiacoliATCC25922andListeria innocua Seeliger ATCC 33090 inoculated on lettuce surface effectively, with 3.5–4.0 log CFU/g reduction for bothduringstorage.Moreover,themodifiedGompertzmodelprovidedagoodfitnesstothesanitisingresults duringstorage,withhighestR2 inAEWgroupforE.coli(0.99)andincombinationgroupforL.innocua(1.00), respectively.Inaddition,thephysicochemicalpropertiesoforganiclettucetreatedbyeachsanitisingtreatment werenotchangedsignificantlyduringstorage.Epifluorescencemicroscopyandatomicforcemicroscopy(AFM) revealed that the cell permeability and morphology of E. coli and L. innocua were changed after sanitising treatments,withdamagedcellmembraneanddisorderedcellularstructureindifferentdegrees.Besides,thesize ofcellsbecamesmalleraftercombinedsanitisingtreatment,with2.12and1.24μm2 forE.coliandL.innocua, respectively, indicating some cytoplasmleakage. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE)showedthenumberandintensitiesoftheproteinbandsofE.coliwerereduced,whilethoseof L. innocuaremainedsimilaraftersanitisingtreatments.TheresultssuggestthatlowconcentrationAEWcombined withLAisapotentialeffectiveapproachtosanitiseorganicproduce.
... In this regard, several sanitization methods have been proven to be effective to eliminate both, pathogenic microorganisms and pesticide residues (Warriner & Namvar, 2013;Wu, An, Li, Wu, & Pan, 2019). Electrolyzed water (EW) is a promising alternative for food decontamination due to its cost efficiency, easy of application, effective decontamination and has no detrimental effects neither on public health nor on the environment (Rahman, Ding, & Oh, 2010). It can be produced with tap water with no added chemicals, other than sodium chloride. ...
EW has been proposed as a sanitization method for home use to reduce chemical and biological hazards in fresh products. Most studies have evaluated exposure times of 1–10 min which may be too long for processing fresh produce. The aim of this work was to evaluate if short exposure times (15, 30 or 45 s) to electrolyzed water (EW – 50 ppm of free chlorine) were enough to significantly reduce Salmonella spp counts and Imidacloprid concentrations in lettuce. Results showed that EW treatment of 45 s achieved a reduction of 4 log CFU/g in the Salmonella spp counts and a reduction of 48,57% in Imidacloprid concentrations. As to quality parameters, neither texture profile nor flavor were affected by the treatment. The fact that only 45 s were enough to effectively reduced Salmonella spp and Imidacloprid makes the EW treatment an ideal sanitization method for lettuce in both the industry and the household.
... Neutral electrolyzed water (NEW) is gaining importance 49 in the food industry mainly due to its effective antimicrobial activity, non-corrosiveness, 50 environment-friendly properties, in situ production at low cost, and safe handling (Aider et al.,51 2012; Jiménez-Pichardo et al., 2016). Neutral electrolyzed water (NEW) was obtained from an 52 electrolytic process using sodium chloride (NaCl) solution (0.1-1% w/v) that generates highly 53 oxidizing chlorine species in automated dispensers, whose titer is usually measured as total 54 available chlorine (TAC) (Rahman et al., 2010). Several compounds are produced, and the most 122 One mL of the bacterial mixture was treated separately with 9 mL of NaClO or NEW at 50 mg/L 123 TAC, and after one min 1 mL from each treatment was filtered and fixed on a 0.22 µm pore size 179 On each sampling day, the natural microflora was determined. ...
Salmonella is the most common pathogen in poultry associated to foodborne outbreaks. There is concern about the use of sodium hypochlorite (NaClO) during antimicrobial interventions in broiler chickens processing, due to trihalomethanes (THMs) generation through oxidation of organic matter. In this study, we showed the effectiveness of neutral electrolyzed water (NEW) in broiler chickens, and their physicochemical properties after antimicrobial intervention. NEW showed 10 times higher antimicrobial effect on Salmonella pure culture than NaClO treatments but similar results were achieved on inoculated chicken carcasses. The mechanism of action of NEW was revealed by microscopic studies, showing cell swelling and morphological changes on membrane. NEW was effective in reducing total viable counts and coliforms on broiler chicken carcasses, without color and pH modification. No THMs were detected on chicken meat using 50 mg/L of either antimicrobial agent, but when using higher concentration THMs were generated. Only 0.037±0.001 μg/kg of chloroform was detected after ≥100 mg/L NEW treatments, whereas bromoform and chlorodibromomethane were generated after similar concentration of NaClO treatments. NEW represents a safe alternative for antimicrobial broiler chicken intervention due to competitive production cost, safe handling, low corrosion capacity, and low toxicity due to lack of by-products generation.
... Firstly, at the near-neutral pH chlorinated solution, the predominant FAC species is hypochlorous acid. It has stronger biocidal capacity than hypochlorite ion, which is the predominant species in high pH NaOCl liquid (Rahman et al., 2010;Waters and Hung, 2013). Besides, the high oxidation-reduction potential (ORP) in the electrolyzed water is regarded as the primary factor yielding microbial inactivation. ...
... The authors also reported that TDS treatment was more effective at 25 C than 4 C, indicating cell membrane fluidity was dependent on temperature. The combined effects of temperature and disinfectant treatment on inactivation of bacteria have been demonstrated (Beuchat and Scouten, 2002;Rahman et al., 2010;Choi et al., 2015). Generally, the TDS was more effective at room temperature (25 C) than at refrigeration temperature (4 C) (Kim et al., 2005;Choi et al., 2015;Koo et al., 2018). ...
The effects of 3 ethanol levels (30, 50, and 70%) with and without thiamine dilaurylsulfate (TDS; 1,000 ppm) were evaluated for the reduction of natural mesophilic aerobic bacteria (MAB), coliforms, and inoculated Salmonella Typhimurium (S. Typhimurium) in chicken skin. The chicken skin was inoculated with a 7 log cfu/mL suspension of S. Typhimurium. Loosely, intermediately, and tightly attached cells were recovered from chicken skin through shaking at 200 rpm for 5 min, stomaching for 1 min, and blending for 1 min, respectively. Increasing the ethanol concentration reduced the number of MAB, coliforms, and S. Typhimurium on the chicken skin, whereas TDS treatment without ethanol was not effective. Intermediately and tightly attached microorganisms (total MAB, coliforms, and S. Typhimurium) were more resistant to chemical disinfectants than loosely attached microorganisms. The combination of 70% ethanol with TDS was most effective than the combination of TDS with lower concentrations of ethanol in reducing populations of loosely, intermediately, and tightly attached MAB (by 1.88 log cfu/g, 1.21 log cfu/g, and 0.84 log cfu/g, respectively), coliforms (by 1.14 log cfu/g, 1.04 log cfu/g, and 0.67 log cfu/g, respectively), and S. Typhimurium (by 1.62 log cfu/g, 1.72 log cfu/g, and 1.27 log cfu/g, respectively). However, the chicken skin treated with higher concentrations of ethanol was tougher (P
... The low concentration electrolyzed water is newly developed with a relatively high pH of 6.2-6.5 and a concentration of free chlorine (almost all hypochlorous acid) about 2-5 mg/L. The hypochlorous acid (HOCl) is the most effective form of chlorine compounds that would inhibit glucose oxidation by chlorineoxidizing sulfhydryl groups of certain enzymes important in carbohydrate metabolism (Rahman, Ding, & Oh, 2010). After combining with ultrasound, the bactericidal effect was significantly promoted compared with those adopted one strategy alone since the ultrasonication would promote permeability of ozone or electrolyzed water in the biofilms, partially disrupt biofilm structure and cell membrane, and eventually lead to cell lysis. ...
... Chemical methods are effective and more economically efficient compared to physical and biological methods (Meireles, Giaouris, & Simões, 2016). The drawbacks of using chemical disinfectants and sanitizers are potential harmful effects on human health and the environment due to formation of secondary components (chlorine) (Shen, Norris, Williams, Hagan, & Li, 2016), corrosive effects on the equipment (ozone and PAA) (Qu, Jiang, Li, Bai, & Zhou, 2008), and formation of offflavors and off-odors (PAA) (Van de Velde, Güemes, & Pirovani, 2014). ...
Listeria monocytogenes, in fresh and ready‐to‐eat produce such as whole fresh apples, is of concern as there is no “kill step” in their packing process that would eliminate the pathogenic bacteria. Recent listeriosis outbreaks revealed that insufficient cleaning and sanitation practices in fresh apple packing houses may lead to contamination of fruit with L. monocytogenes. This article discusses three fundamental aspects for ensuring microbiological safety of fresh apples: protection of fresh apples from microbial contamination during the packing process, decontamination intervention techniques, and the challenges in removal of L. monocytogenes from fresh apples. Currently used and novel methods of fresh produce decontamination are discussed and evaluated on their usefulness for the apple packing process. Additionally, present regulatory requirements, possible routes of produce contamination, and bacteria attachment and survival mechanisms are described. Optimum methods for microbial decontamination of whole fresh apples are still to be determined. Critical aspects that should be considered in developing the interventions include apple morphology, conditions and scale of the packing process, and influence of the interventions on apple quality. Evaluation of the currently used and emerging decontamination methods indicated that the hurdle technology and rotating use of sanitizers to avoid development of bacterial biofilm resistance may give the best results, although not conclusively.
... The surviving total aerobic bacteria on celery were significantly decreased from 7.61 to 2.98 log CFU/g, when the exposure for 7 min . Meanwhile, Rahman, Ding, and Oh (2010) also showed the reduction in the populations of L. monocytogenes increased from 4.98 to 7.42 log CFU/mL when EW temperature was raised from 4 to 50 C. However, Liu, Tan et al. (2017) reported that an increase in temperature (from 20 to 50 C) of EW did not achieve a significant reduction in E. coli O157:H7 and L. monocytogenes on broccoli, that might be due to the partial loss of ACC occurred when the high temperature was used (Rahman, Khan, & Oh 2016). ...
With a growing demand for safe, nutritious, and fresh-like produce, a number of disinfection technologies have been developed. This review comprehensively examines the working principles and applications of several emerging disinfection technologies. The chemical treatments, including chlorine dioxide, ozone, electrolyzed water, essential oils, high-pressure carbon dioxide, and organic acids, have been improved as alternatives to traditional disinfection methods to meet current safety standards. Non-thermal physical treatments, such as UV-light, pulsed light, ionizing radiation, high hydrostatic pressure, cold plasma, and high-intensity ultrasound, have shown significant advantages in improving microbial safety and maintaining the desirable quality of produce. However, using these disinfection technologies alone may not meet the requirement of food safety and high product quality. Several hurdle technologies have been developed, which achieved synergistic effects to maximize lethality against microorganisms and minimize deterioration of produce quality. The review also identifies further research opportunities for the cost-effective commercialization of these technologies.
... The SAEW has attracted much interest, because it contains low free chlorine, has less Cl 2 gas emissions, has low corrosive effects on surfaces, and is a highly effective antimicrobial agent with limited phytotoxic effects compared to hypochlorous acid derivatives. 11 Therefore, SAEW has been considered as a medical disinfectant due to the corrosive effects of StAEW. 12 Mixed electrolyzed water (MEW) is the name of a preparation that obtained mixing anolyte and catholyte (in an equal volume of each in our case). ...
Electrolyzed water (EW) is a widely used disinfectant agent with high oxidation–reduction potential (ORP). Although EW has been used in many areas, such as food hygiene, agriculture, and animal husbandry, the studies presented in the literature are not enough to clarify the toxic effects of EW. The aim of this study is, therefore, to produce EWs at different pH, ORP, and chlorine concentrations and to assess their safety in terms of toxicology. At the beginning of the study, the antimicrobial activity of the EW types with respect to bacteria and fungus was investigated. EWs below pH 7 were all effective in inactivating Enterococcus hirae, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans completely. In vitro studies of cell cultures revealed that different concentrations of EWs were not cytotoxic for the L929 cells under 10- to 80-fold dilutions. In addition, it has been determined that produced EWs did not have irritation potential, according to the in vitro EpiDerm ™ , reconstituted skin irritation test in the frames of biocompatibility tests. For the mucous membrane irritation test, the hen’s egg test-chorioallantoic membrane experiment was performed, and EWs were found to have no eye irritation. In conclusion, it has been shown that produced EWs with antimicrobial efficacy were found to be safe for skin and eye according to in vitro biocompatibility study studies. Thus, the establishment of a technological infrastructure for the EW production and the use of produced EW as an effective disinfectant in the food, medical, and agricultural areas should be encouraged.
... The main factors that determine the sanitizing effects of electrolyzed water are pH, oxidation-reduction potential (ORP), and free available chlorine (FAC) concentration (Zhang et al. 2018b). According to the literature, an increase in the pH is related with a decrease in the FAC concentration and in the ORP (Rahman et al. 2010). On the one hand, high ORP can inflict oxidative damage to the bacterial cells, leading to necrosis. ...
One of the main problems in the food industry is the formation of biofilms on food contact surfaces. These bacterial communities show high resistance against the commonly used disinfectants, which makes them difficult to eradicate causing economic losses and threatening the quality of the products and the health of consumers. Several studies have reported the use of atmospheric pressure plasma technologies to provide antibacterial properties to a wide range of materials through the deposition of coatings that either avoid the initial attachment of bacteria to the surface or kill the attached bacteria before the mature biofilm is formed. These technologies avoid the use of extreme pressures and temperatures during the deposition process, thus preserving the properties of the substrate, which makes them interesting for their potential application in the production of anti-biofilm food contact materials. This paper reviews different approaches that use atmospheric pressure plasma technologies to combat bacterial colonization and biofilm formation on materials of relevance for the food industry. Three types of approaches are identified and their suitability in the food industry is discussed.
... E. coli, Salmonella spp., Staphylococcus spp. etc., were predominantly may present in agriculture soils, improperly composted manures, and/or irrigation water may contribute to contaminate the RSVs during production, harvest handling, transportation and storage and even during display (Alam et al., 2015;Rahman et al., 2010). ...
The presence of undesirable heavy metals, pesticide residues, and microbial contaminants in fresh produces is a worldwide public health concern. This study was undertaken to evaluate the residual pesticides (Diazinon, Malathion, Cypermethrin, Dimethoate, Quinalphos, and Chloropyrofos), heavy metal contamination (Pb, Cd, and Cr), and microbiological quality and safety of 4 common raw salad vegetables (RSVs) samples from different local markets in Dhaka. Results showed the presence of heavy metals residues were within the acceptable limits of local and international standards. None of the above-mentioned pesticides were found in tomato and cucumber samples but presence of Dimethoate was noticed in 13 coriander samples (12.94–158.3 μg/kg) and 7 lettuce samples (9.6–74.8 μg/kg) exceeding the maximum permissible limit of EU guideline. The microbiological analysis showed irrespective of RSV types, total aerobic bacteria was present in higher number (4.0–7.0 log CFU/g), whereas 3.36–5.57 log CFU/g coliform count was recorded. In comparison with retail markets, lower level of total aerobic, and coliform bacterial presence was observed in the samples collected from sophisticated shops, but presence of E. coli and Salmonella spp. were evident in more than 60% samples in these shops. However, 50% and 33% samples from wholesale and retail markets respectively were noticed to be contaminated with Staphylococcus spp. Irrespective of RSV types, isolated E. coli were found resistance to 2–5 different antibiotics, where Salmonella spp. isolated from cucumber and coriander leaves showed resistance against 4–8 different antimicrobials. Therefore, the study results demonstrated that, the presence of residual pesticides, multidrug resistant E. coli and Salmonella spp. in the RSV samples posing concern when consumed raw. The regulatory bodies are expected to monitor and ensure the overall quality standards are in place and practiced by food producers and marketers responsible for handling and distribution of RSVs.
... Firstly, at the near-neutral pH chlorinated solution, the predominant FAC species is hypochlorous acid. It has stronger biocidal capacity than hypochlorite ion, which is the predominant species in high pH NaOCl liquid (Rahman et al., 2010;Waters and Hung, 2013). Besides, the high oxidation-reduction potential (ORP) in the electrolyzed water is regarded as the primary factor yielding microbial inactivation. ...
The membrane-less electrolyzed water (MLEW) has been reported to possess antimicrobial effects against a variety of microorganisms and is considered as an alternative of traditional disinfectants. In the study, the inactivating efficiency was evaluated by using MLEW with free available chlorine (FAC) at concentrations of 50 and 100 mg/L against food-borne related microorganisms, including Enterohaemorrhagic Escherichia coli (ECHC), Salmonella spp. and Staphylococcus aureus individually. D-value (decimal reduction time) was applied for evaluating the antimicrobial ability of MLEW. D-values of ECHC, Salmonella, and S. aureus were about 120 sec, 5 sec and 5 sec, respectively. Our study demonstrated that MLEW is very effective in reducing the food-borne microbial contamination.
... LcEW containing 2e5 mg/L of residual chlorine has an ORP range of 941e1010 mV, which is outside the preferable redox potential range of most microorganisms (Park, Hung, & Chung, 2004). LcEW has been reported to act as an effective bactericidal agent and may represent a suitable sanitiser for organic produce, as it does not affect the quality of the produce and is safe for use (Koseki, Yoshida, Kamitani, Isobe, & Itoh, 2004;Rahman, Ding, & Oh, 2010a, 2010b. Thus, LcEW might replace the widely used strong acidic EW, especially for organic produce. ...
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.
... Electrolyzed water (EW) is produced in an electrolysis chamber which contains hydrogen chloride (HCl) solution or dilute salt (NaCl) [52]. According to the different devices, electrolyte and electrolysis conditions, EW can be classified into the following categories: acidic electrolyzed water, neutral electrolyzed water and alkali electrolyzed water [53]. ...
As the situation of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is still deteriorating, there has been a huge increase in the demand and use of disinfectants. Electrolyzed water (EW), as a novel broad-spectrum disinfectant and cleaner, has been widely used for several years. EW can be produced in an electrolysis chamber which contains dilute salt and tap water. It is an effective antimicrobial and antibiofilm agent, with several advantages such as on-the-spot, cheap, environmentally friendly and safe for human beings. Therefore, EW holds potential significance for high-risk settings in hospitals and other clinical facilities. EW can also be applied for wound healing, advanced tissue care, and dental clinics. The present review article highlights the latest developments and new perspectives of EW, especially in clinical fields. Furthermore, the main action modes of antibiofilm and antimicrobial will be summarized.
... Slightly acidic electrolyzed water (SAEW) is known as a novel disinfectant for egg sterilization due to its broad-spectrum, high-efficiency, and no-residue qualities (Huang et al., 2008;Rahman et al., 2010). The main effective form of chlorine compounds in SAEW is hypochlorous acid (HOCl), which has strong antimicrobial activity (Cao et al., 2009). ...
Conventional chemical disinfectants used for egg disinfection could result in toxic residue and endanger hatchability, chick quality, and pullet growth performance. Slightly acidic electrolyzed water (SAEW) is known as a novel disinfectant for egg sterilization due to its high efficiency and no residue. In this study, a comprehensive assessment of slightly acidic electrolyzed water and benzalkonium bromide solution (BBS) used in the disinfection channel was conducted to assess the microbial count, eggshell quality, and hatchability concomitantly. The results show that the sterilization efficiency of SAEW increased with an increase in available chlorine concentration (ACC), spraying volume, and sterilization duration. SAEW with an ACC of 150 mg/L and 10,000 mg/L benzalkonium bromide solution had the same sterilization rates of approximately 86.2% at a spraying volume of 0.5 mL/egg and sterilization duration of 180 s. Neither had significant effect on eggshell strength or thickness. The eggshell cuticle quality in the benzalkonium bromide group was significantly higher than the control group (no disinfection) and the 150 mg/L SAEW group. The embryo weight, relative embryo weight, hatchability, and embryonic mortality in the SAEW group had no significant differences of those in the benzalkonium bromide group. SAEW should be more popular because of its simple preparation, low cost, and no residue. Our results indicate SAEW is an alternative disinfectant for the sterilization of hatching eggs instead of conventional chemical disinfectants, such as benzalkonium bromide, and give a recommendation is using SAEW as a disinfectant with 150 mg/L ACC, 0.5 mL/egg spray volume, and disinfection for 180 s in the novel disinfection channel.
... Further exploration of low concentrations of AEW is needed to determine the minimum inhibitory concentration, which will help us screen out the most ideal AEW concentration. Of course, the problems must be faced that the fine-tuning of AEW is challenging to achieve at this moment, such as the irregularity of dilution concentration (37), the stability of water pressure (38), and so on. These are all to be resolved. ...
The vaginal microbiota, dominated by Lactobacilli, plays an important role in maintaining women's health. Disturbance of the vaginal microbiota allows infection by various pathogens such as Gardnerella spp. (GS) and related anaerobic bacteria resulting in bacterial vaginosis (BV). At present, the treatment options for BV are extremely limited. Treatment of antibacterial drugs and vaginal acidification are the two primary therapeutic methods. Acid electrolyzed water (AEW) is known to inactivate microorganisms and is considered a medical application in recent years. Studies have found that Lactobacillus acidophilus (LA) probiotics helps to inhibit GS-induced BV. Our study took GS and LA as the research object, which aims to explore AEW as a potential alternative therapy for BV and its underlying mechanisms. We first obtained the pH of AEW (3.71–4.22) close to normal vaginal pH (3.8–4.5) to maintain normal vaginal acidification conditions. Plate counting experiments showed that AEW (pH: 4.07, ORP: 890.67, ACC: 20 ppm) (20 ppm) could better inhibit the viability of GS but had a more negligible effect on LA. Then, we preliminarily explored the possible mechanism of AEW anti-GS using cell biology experiments and transmission electron microscopy. Results showed that the membrane permeability was significantly increased and the integrity of cell membrane was destroyed by AEW in GS than those in LA. AEW also caused protein leakage and cell lysis in GS without affecting LA. Meanwhile, AEW induced a number of reactive oxygen species (ROS) production in GS, with no obvious LA changes. Finally, we found that 20 ppm AEW exhibited excellent antibacterial effect on the vaginal secretions of women diagnosed with BV by Amsel criteria and sialic acid plum method. Taken together, our findings manifest that 20 ppm AEW has an excellent antibacterial effect in GS with less effect on LA, which might be expected to become a potential therapy for BV.
... Although having potential antimicrobial activity, AEW has a relatively low pH of 2-3 at which Cl2 is easy to volatilize into the air which consequently poses threat to health. Moreover, AEW may be corrosive to organic materials due to its high acidity, which ultimately limits its application (Rahman et al. 2010). ...
... In our previous study, a potable sanitising unit using NaHCO 3 and NaCl as electrolytes to generate slightly acid electrolysed water (SAEW) was developed, which exhibited good antibacterial efficiency . In addition, SAEW has been reported to have similar, or greater bactericidal activity against foodborne pathogens than strong acid electrolysed water (Rahman, Ding, & Oh, 2010). And it is non-corrosive due to its near-neutral pH. ...
Ice is widely used for the preservation of perishable seafood but not much effective in killing bacteria. Herein, in this study, we aimed to investigate the effect of slightly acid electrolysed water (SAEW) ice on the microbial spoilage together with the quality parameters to elucidate the underlying preservative mechanism. The results indicated that SAEW ice exhibited inhibitory activity toward polyphenol oxidase (PPO) and acid phosphatase (ACP) with 55.3% and 61.9% reduction of activity at day 7, respectively, along with less discolouration and the lowest K-value of shrimp. Besides, the growth of aerobic mesophilic and psychrotrophic bacteria was retarded by SAEW ice treatment (2.4 and 0.4 log CFU/g reduction, respectively). 16S rDNA-based Illumina sequencing elucidated that SAEW ice efficiently retarded the growth of Proteobacteria. Specifically, the growth of major spoilage genus presented in tap water (TW) ice treated shrimp (Shewanella, Vibrio, and Aeromonas) and NaCl ice treated shrimp (Psychrobacter) was inhibited in SAEW ice treated shrimp, which further led to the smallest increase of putrescine and cadaverine, together with the lowest values of pH and TVB-N during storage. The sensory results indicated that SAEW treatment maintained the quality of shrimp during storage in terms of colour, appearance, and texture. Overall, the SAEW ice exhibited a promising preservative effect on shrimp.
... The cell envelope and dehydrogenase of microbials can be damaged by the main ingredients (HOCl and ClO − ) of EW, when the contact between EW droplets and microbials occurs (Nan et al. 2010;Zeng et al. 2010). Unlike other chemical disinfectants, SAEW and NEW caused less corrosion of surfaces and damages to both animal and human health, because no hazardous chemicals were added in their production (Deza, Araujo, and Garrido 2007;Guentzel et al. 2008;Rahman, Ding, and Oh 2010). A wet scrubber with SAEW spray with 70 and 100 mg L −1 available chlorine concentrations (ACCs) significantly and moderately reduced airborne CB emitted from a layer breeding house (P < 0.01) and showed similar removal efficiencies (~40%) (Zheng et al. 2016a). ...
Airborne microorganisms, especially the pathogenic microorganisms, emitted from animal feeding operations (AFOs) may harm the environment and public health and threaten the biosecurity of the farm and surrounding environment. Electrolyzed water (EW), which was considered to be an environmentally friendly disinfectant, may be a potential spraying medium of wet scrubber for airborne microorganism emission reduction. A laboratory test was conducted to investigate the airborne bacteria (CB) removal efficiency of the wet scrubber by EW spray with different designs and operating parameters. Both the available choline (AC) initial loss rate and AC traveling loss rate of acidic electrolyzed water (AEW; pH = 1.35) were much higher than those of slightly acidic electrolyzed water (SAEW; pH = 5.50). Using one spraying stage with 4 m sec⁻¹ air speed in the duct, the no detect lines (NDLs) of SAEW (pH = 5.50) for airborne Escherichia coli, Staphylococcus aureus, and Salmonella enteritidis removal were all 50 mg L⁻¹, whereas the NDLs of AEW (pH = 1.35) for airborne E. coli, S. aureus, and S. enteritidis removal increased to 70, 90, and 90 mg L⁻¹, respectively. The NDLs of SAEW (pH = 5.50) for airborne E. coli, S. aureus, and S. enteritidis were lower than those of AEW (pH = 1.35) at single spraying stage. Increase in the number of stages lowered the NDLs of both SAEW (pH = 5.50) and AEW (pH = 1.35) for airborne E. coli, S. aureus, and S. enteritidis. EW with a higher available chlorine concentration (ACC) was needed at air speed of 6 m sec⁻¹ to reach the same airborne CB removal efficiency as that at air speed of 4 m sec⁻¹. The results of this study demonstrated that EW spray wet scrubbers could be a very effective and feasible airborne CB mitigation technology for AFOs.
Implications: It is difficult to effectively reduce airborne bacteria emitted from animal feeding operations (AFOs). Electrolyzed water (EW) with disinfection effect and acidity is a potential absorbent for spray in wet scrubber to remove microorganisms and ammonia. Based on the field test results, a laboratory experiment we conducted this time was to optimize the design and operation parameters to improve the airborne bacteria removal efficiency. A better understanding of the EW application in the wet scrubber can contribute to the mitigation of airborne bacteria from animal houses and improve the atmosphere air quality.
... Although several disinfectants are extensively used, their limitations such as low efficiency, application site impact, chemical residues, and cost have been reported [2,3]. Hypochlorous acid (HOCl) is a comprehensive disinfectant that is sustainable and environment-friendly; therefore, it is considered a practical alternative [4]. It is an emerging wide-spectrum disinfectant that is produced by passing a salt or acid solution through an electrolytic cell and is commonly known as electrolyzed water (EW). ...
Hypochlorous acid (HOCl), also known as electrolyzed water (EW), is a sustainable and environment-friendly disinfectant, which can comply with food safety regulations. In this study, HOCl was produced through HCl electrolysis using an acrylic electrolyzing reactor without a diaphragm between iridium oxide electrodes coated with titanium. The Box–Behnken design (BBD) was adopted to study the effects of feed water flow rate (FR), pH, temperature, electric voltage, acid concentration (AC), and acid dosing pump stroke (APS) on HOCl production measured as available chlorine concentration (ACC). Then, optimum parameters were explored using response surface methodology (RSM). The proposed quadratic models defined the relationship between HOCl production and the process variables. The models were statistically significant as shown by analysis of variance. The optimum operating parameters for HOCl production were 6.5 L/min, pH 7.5 at 20 °C, 3.8 volts, 6% AC, and APS at 3%. The FR, AC, and APS were significant parameters, and no substantial effect was observed for pH and temperature of feed water or the variation in current–voltage. High FR caused a conspicuous drop, and the high voltage showed a slight increase in ACC. However, an increase in AC and APS significantly enhanced the ACC, although the pH dropped below 5.0–6.5, indicating the presence of other chlorine-based compounds apart from HOCl. RSM model validation through experimental results indicated that the proposed model could effectively provide a relationship between ACC and process variables. Additionally, an artificial neural network model was tested to predict the ACC that showed good fitness to the experimental results.
... The basic properties of EW include available chlorine concentration (ACC), pH and oxidation-reduction potential (ORP), which are regarded as three main factors directly influencing EW's sanitizing efficacy. Numerous studies have found out the interaction effects among them, such as pH value could alter the formation of chlorine species and the ORP value could decrease markedly when the pH increased, which had mutual effects during the process of sterilization [12]. On the other hand, free radicals (such as hydroxyl radicals ( OH)) are also considered as germicidal components of EW, although some previous studies' results were conflicting [13,14] (Figure 1a). ...
As one of the most promising sterilization agents for microbial control in food industry in recent decades, electrolyzed water (EW) can be produced from diluted NaCl solution, and exhibits strong broad-spectrum bactericidal efficiency due to the synergistic effect of available chlorine concentrations, pH and oxidation reduction potential. To date, numerous studies have demonstrated the antimicrobial activity of EW against various kinds of microorganisms both in vitro and in vivo. However, the exact antimicrobial mechanisms of EW have not been determined at present, limiting its widespread application. In this review, we provide an overview of latest production equipment of EW, and briefly summarize the current advances of germicidal factors and antimicrobial mechanisms of electrolyzed water on different states of microorganisms. In addition, studies about hurdle enhancement of EW combined with other technologies are also discussed, providing guidelines for improving food safety and food quality both in conventional and organic food industry.
... NaOCl also has been widely used in sterilization in our country, but its security is a concern. e slightly acidic electrolyzed water (SAEW), as an alternative and novel method with great potential for sterilization, has recently received a great deal of attention for its sanitizing efficacy and environmentally friendly nature [10][11][12][13]. Hypochlorous acid (HClO) produced by SAEW can inactivate the microbial cell via improving the oxidation of lipids and protein compounds as well as resulting in a modification in the electron transfer mechanism of microorganisms [14]. ...
In the present study, the synergetic effect and mechanism of ultrasound (US) and slightly acidic electrolyzed water (SAEW) on the inactivation of Escherichia coli (E. coli) were evaluated. The results showed that US combined with SAEW treatment showed higher sanitizing efficacy for reducing E. coli than US and SAEW alone treatment. US and US combined with SAEW treatments resulted in smaller particle size of E. coli compared to the control and SAEW treatment. In addition, US combined with SAEW treatment induced the highest potassium leakage. However, the highest protein leakage was recorded in US treatment. Moreover, scanning and transmission electron microscopy analysis revealed that the greatest damage of the appearance and ultrastructure of E. coli was achieved after US combined with SAEW treatment. The synergetic effect was also confirmed by CLSM analysis. Fluorescence spectroscopy suggested that treatments of US, SAEW, and US combined with SAEW changed protein conformation of E. coli. Overall, the present study demonstrated that the sterilization mechanism of US combined with SAEW treatment was decreasing the particle size and disrupting the permeability of cell membrane and the cytoplasmic ultrastructure as well as changing protein conformation of E. coli.
Electrolyzed water (EW) is a novel bactericide in the food industry, which has received increasing attention. It has been shown to be an effective microorganism inactivation agent without bringing significant environmental hazard. EW parameters and microorganism properties can greatly influence the decontamination efficacy of EW. This chapter aims to review the influencing factors on microbial decontamination of EW. In addition, the mechanisms underlying the inactivation effect of EW on microbes were summarized. Apart from the lethal effect, the potential actions of EW on physiological states of microbes were also discussed. The extended applications of EW on spore inactivation and microbial toxin degradation were covered in the last part of this chapter.
Pesticides can prevent or control diseases, insects, grasses, and other harmful organisms that endanger agroforestry, as well as purposefully regulate plant and insect growth. It is proved that pesticides can promote the development of modern agriculture. However, most pesticides, if not used properly, will not only cause waste but also lead to poisoning accidents and harmful effect for human and animal health. In recent years, many researches have been extensively conducted on various methods to eliminate pesticide residues, which can be generally divided into physical methods, chemical methods, and biological methods. Among the obtained achievement, it was found that electrolyzed water (EW) has a good elimination effect on pesticide residues on food in addition to its other well-known capabilities that many studies reported that EW showed strong ability to eliminate the foodborne pathogens from different food matrixes. This chapter focused on the removal of pesticide on food by electrolyzed water. Removal efficacy and mechanism of different pesticides on foods and the effect of different factors on the removal efficacy were reviewed. The results showed that EW has obvious effect on the removal of pesticide residues on food, without significant quality decay, which will have a good application prospect in the future.
The aim of this study was to investigate the effect of slightly acidic electrolyzed water (SAEW) and ultrasound (US) combination on the inactivation of Vibrio parahaemolyticus in vitro and in fish samples. The bacterial log reductions caused by the US and SAEW treatment for 15 min were 0.99 and 2.63 log CFU/mL in vitro, respectively, while SAEW‐US combination achieved a 3.10 log reduction. MTT assay and protein leakage test showed that SAEW‐US combination impaired cell viability and damaged cell membrane. In addition, compared to the US or SAEW treatment, SAEW‐US combination induced higher reactive oxygen species (ROS) production, more apoptotic cells, and severer damage in bacterial cells. In spiked sliced tilapia samples, SAEW‐US combination caused about 2 log reduction of inoculated pathogen. In conclusion, these findings demonstrate that SAEW‐US combination could be potentially developed as an alternative strategy to control Vibrio parahaemolyticus contamination in aquatic foods.
As food industry flourished, the use of EW as a novel sanitizing agent has gained interest worldwide. The chapter reviews recent progress in the application of EW in fruits and vegetables industry, summarizing its efficacy on disinfection and pesticide removal during their processing, and disease control along with inhibiting moth infestation throughout storage as well as the effect on physiochemical properties, chemical components, and postharvest physiology. Furthermore, it specially generalized the application of EW in the field of sprouts vegetables (our researching focus) to open up a new way for the development of functional food. It indicated that EW has sufficient obliterating efficacy on spoilage or pathogenic microorganisms, pesticide residues, and some insect pests existing on fruits and vegetables without compromising sensory and nutritional quality of them in most occasions. Besides, the employment of EW to sprouts vegetables makes those healthful components such as CABA and flavonoids accumulated. However, optimal processing parameters such as washing time along with physiochemical properties of EW need further selection. And, hurdle technology should not be tolerated to maximize treatment efficacy and prolong the shelf life of fresh produce. In brief, EW has a promising prospect in future utilization of fruits and vegetables.
Sanitation is a compulsory procedure in the food industry. As it involves production downtime, it imposes overhead costs. One way to obtain higher profit margins is to cut the overhead costs of sanitation. Eco-innovative cleaners and sanitisers such as electrolysed water have a high potential to reduce sanitation costs. The only ingredients of electrolysed water are salt and distilled water. Some major food industries invest in expensive commercial electrolysed water generators to produce different types of electrolysed water (acidic, alkaline, and neutral). Smaller food industries can install an electrolysed water generator independently, but they need to determine the optimum and most economical electrolysing parameters. Different electrolysed water generators employ different electrolysing parameters to produce electrolysed water with the same physical and chemical properties. Thus, in this work, electrolysing parameter screening methods are demonstrated. A laboratory-scale electrolysed water generator was used to investigate the effects of different electrolysing parameters (voltages (1–20 V), electrolysis times (1–15 minutes), and sodium chloride concentrations (0.05–3%)) on the physical and chemical properties (pH, oxidation-reduction potential (ORP), and available chlorine concentration (ACC)) of electrolysed water (both acidic and alkaline). These screening methods were essential to determining the range of electrolysing parameters to use for the optimisation experiments and ascertaining the generator's limit. The subsequent optimisation experiments aimed to ensure the generator could be used for a long period and that economical usage conditions were achieved. The screening experiments helped to reduce the parameter variations in these experiments and provide reliable data on electrolysed water properties.
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.
Electrolyzed oxidizing water (EOW) is one of the promising novel antimicrobial agents that have recently been proposed as the alternative to conventional decontamination methods such as heat and chemical sanitizers. Acidic EOW with pH ranging from 2 to 5 is regarded most applicable in the antimicrobial treatment of vegetables and meats. Neutral and alkaline electrolyzed water have also been explored in few studies for their applications in the food industry. Neutral electrolyzed water is proposed to solve the problems related to the storage and corrosion effect of acidic EOW. Recently, the research focus has been shifted toward the application of slightly acidic EOW as more effective with some supplemental physical and chemical treatment methods such as ultrasound and UV radiations. The different applications of electrolyzed water range from drinking water and wastewater to food, utensil, and hard surfaces. The recent studies also conclude that electrolyzed water is more effective in suspensions as compared with the food surfaces where longer retention times are required. The commercialization of EOW instruments is not adopted frequently in many countries due to the potential corrosion problems associated with acidic electrolyzed water. This review article summarizes the EOW types and possible mechanism of action as well as highlights the most recent research studies in the field of antimicrobial applications and cleaning. Electrolyzed water can replace conventional chemical decontamination methods in the industry and household. However, more research is needed to know its actual mechanism of antimicrobial action along with the primary concerns related to EOW in the processing of different food products.
Providing consumers with fresh and safe fruit can greatly increase their access to recommended daily intake of phytonutrients. Thus, this study investigated the impact of dipping in alkaline electrolyzed water (AEW) and dipping duration on the physico‐chemical, phytonutrients, and microbial load on ‘Granny Smith’ apples. Apples treated with AEW (200 and 300 mg L‐1) were compared to sodium hypochlorite (NaOCl, 200 mg L‐1) and to non‐treated (control) under dipping durations of 10 and 15 min. Apples treated with AEW maintained titratable acidity (TA) and total soluble solids (TSS) compared to other treatments (p > 0.05). Interaction of treatments and storage duration had a significant impact (p ≤ 0.05) on total phenolics and flavonoids contents. Apples treated with AEW better maintained antioxidant capacity compared to control. Treatments with AEW resulted in ≈2 Log reduction in total aerobic mesophilic bacteria (4.1 Log CFU cm‐2 to 2.2 Log CFU cm‐2) and < 1 Log reduction for yeasts and moulds (3.9 Log CFU cm‐2 to 2.7 Log CFU cm‐2). This study demonstrated the efficacy of electrolyzed water treatment as an alternative to conventional pack‐house practices for apple fruit.
The aim of this study was to assess the antifungal effectiveness of neutral electrolyzed water (NEW) to inhibit the spore germination of post-harvest fungi common in fruits, determine the required available chlorine concentration (ACC) of NEW and to compare it with copper oxychloride (CO) and sterile distilled water (SDW) in vitro. This study evaluated the biological effectiveness of NEW to inactivate pure cultures of 11 different fungi obtained from post-harvest tropical fruits with anthracnose, rottenness or necrosis symptoms. A conidial solution of 1 × 104 spores/mL per culture was prepared and treated with a low, medium and high ACC of NEW (pH 7.0 ± 0.05, 12, 33 and 53 mg/L of ACC and ORP of 850 mV), CO at 0.3 g/L, or sterile distilled water as a control, for 3-, 5- and 10-min contact time. Spore germination of Alternaria alternata, Botrytis cinerea, Cladosporium australiense, Colletotrichum gloeosporioides and C. siamense, Fusarium solani and F. oxysporum, and Lasiodiplodia theobromae was inhibited in 100% by NEW at 12, 33 and 53 ppm ACC; 3,5 and 10 min contact time. Aspergillus niger and A. tamarii required 53 mg/L ACC to inhibit 100% of spore germination. NEW at 33 and 12 mg/L inhibited around 50% and
The aim of this research is to study the influence of ozone on the efficiency of incubating quail eggs. The study had been conducted in the period from 2014 to 2018 under the SIE LLC “EcoDom”. In the course of the experiment the Estonian quail egg were served as an object of research. To carry out the experiment a household ozonizer ”Groza” was used. The Eggs of the first “control” group were disinfected with formaldehyde vapors according to the standard method – 35 ml of 37 % formalin solution + 20 ml of tap water + 20 g of potassium permanganate per 1 cubic metre of volume in a special chamber. The other three groups were ozonized. The eggs of the 2nd experimental group were treated for 10 minutes exposure time, the third – 20 minutes and the fourth – 30 minutes, the ozone concentration in all experimental groups was the same and was 10 mg/m3. After treatment, the eggs were placed for brooding. Biochemical parameters of blood serum were determined by the analyzer ”Microlab-300”. Ozonation of hatching eggs contributes to increase crude protein in the quail’s blood serum by 9.37, 9.65 and 8.57 % compared to the control group. Hatching conditional quails was increased by 43.35 % in comparison with the control group.
Bacteria and their by-products are the primary cause of pulpal and periapical diseases that are one of the most common oral diseases. Root canal treatment (RCT) is the most effective procedure to treat pulpal and periapical diseases with severe infection. RCT aims to eliminate the infection from root canals and place filling materials to seal the space to prevent reinfection. Because of the complicated anatomical structure of the tooth root canal, complete elimination of the bacteria that reside in a root canal and the dentinal tubules via mechanical preparation is extremely difficult, if not impossible. Therefore, antimicrobial endodontic materials are indispensable for infection elimination during RCT. Based on the procedure of RCT, different antimicrobial endodontic materials have been developed for root canal irrigation, medication, and obturation (sealing). This chapter discusses the antimicrobial endodontic biomaterials that are used during the three steps of the RCT. Advantages and limitations of each material are emphasized. In addition, recent developments and future research directions of antimicrobial endodontic biomaterials are presented.
Electrolyzed oxidizing water (EOW) can be considered in the agrofood industry as a new antimicrobial agent with disinfectant, detoxifying, and shelf-life improvement properties. EOW is produced by electrolysis of water, with no added chemicals, except for sodium chloride. The antifungal and detoxifying mechanisms of EOW depend mainly on: pH, oxidation-reduction potential (ORP), and available chlorine concentration (ACC). EOW offers many advantages over other conventional chemical methods, including less adverse chemical residues, safe-handling, secure, energy-saving, cost-effective, and environmentally-friendly. As a result, EOW could be used for the development of safer and more socially acceptable methods for fungi decontamination and mycotoxin detoxification. This review contains an overview of EOW effectiveness to decontaminate non-toxigenic and mycotoxigenic fungi, its safety and efficacy for mycotoxin detoxification, the proposed mechanism of action of EOW on fungal cells, and the chemical mechanism of action of EOW on mycotoxins. Finally, conclusions and future research necessities are also outlined.
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.
Electrolyzed oxidizing water has been estimated that it has strong bactericidal activity and has been widely used as a disinfectant for inactivating microbial organisms. The combined effects of temperature (15–35C), chlorine concentration of electrolyzed oxidizing water (30–70 ppm) and treatment time (1–5 min) on the reduction of Listeria monocytogenes in lettuce were investigated. Reductions of 1.39–2.79 log10 cfu/g were observed in different combinations of the three factors. Also, a quadratic equation for L. monocytogenes inactivation kinetic was developed by multiple regression analysis using response surface methodology. The predicted values were shown to be significantly in good agreement with experimental values because the adjusted determination coefficient () was 0.9578 and the level of significance was P < 0.0001. Besides, average mean deviation (E%), bias factor (Bf) and accuracy factor (Af), which are validation indicators of the model were 0.0218, 1.0003 and 1.0220, respectively. Thus, predicted model showed a good correlation between the experimental and predicted values, indicating success at providing reliable predictions of L. monocytogenes growth in lettuce.PRACTICAL APPLICATIONSElectrolyzed oxidizing water is an important sanitizer, and nowadays it has been widely used in food industry. Lettuce is regarded as a “healthier” food, which is one of the most popular vegetables consumed, whereas many outbreaks caused by L. monocytogenes have been reported until now. According to the model developed in this study, inactivation of L. monocytogenes in lettuce treated with EO water could be predicted by inputting a certain group of environmental factors.
The influence of storage temperature (4, 10, 15, 20, 25, and 30 °C) on the growth of Escherichia coli O157:H7 in beef untreated (control) and treated by acidic electrolyzed oxidizing water (AcEOW) or slightly acidic electrolyzed oxidizing water (SAcEOW) was examined. A Baranyi model was employed to describe growth parameters such as specific growth rate (SGR) and lag time (LT) as a function of storage temperature. SGR increased and LT declined with rising temperatures in all samples. There were no significant differences between the SGR and LT values obtained from beef treated with AcEOW or SAcEOW. Secondary models were established for SGR and LT to evaluate the effects of storage temperature on the growth kinetics of E. coli O157:H7 in treated and untreated beef. Mathematical evaluation was carried out to validate the performance of the developed models.
The efficacy of electrolyzed oxidizing water for inactivating Escherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes was evaluated. A five-strain mixture of E. coli O157:H7, S. enteritidis, or L. monocytogenes of approximately 10(8) CFU/ml was inoculated in 9 ml of electrolyzed oxidizing water (treatment) or 9 ml of sterile, deionized water (control) and incubated at 4 or 23 degrees C for 0, 5, 10, and 15 min; at 35 degrees C for 0, 2, 4, and 6 min; or at 45 degrees C for 0, 1, 3, and 5 min. The surviving population of each pathogen at each sampling time was determined on tryptic soy agar. At 4 or 23 degrees C, an exposure time of 5 min reduced the populations of all three pathogens in the treatment samples by approximately 7 log CFU/ml, with complete inactivation by 10 min of exposure. A reduction of >/=7 log CFU/ml in the levels of the three pathogens occurred in the treatment samples incubated for 1 min at 45 degrees C or for 2 min at 35 degrees C. The bacterial counts of all three pathogens in control samples remained the same throughout the incubation at all four temperatures. Results indicate that electrolyzed oxidizing water may be a useful disinfectant, but appropriate applications need to be validated.
To better quantify the impact of foodborne diseases on health in the United States, we compiled and analyzed information from multiple surveillance systems and other sources. We estimate that foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. Known pathogens account for an estimated 14 million illnesses, 60, 000 hospitalizations, and 1,800 deaths. Three pathogens, Salmonella, Listeria, and Toxoplasma, are responsible for 1,500 deaths each year, more than 75% of those caused by known pathogens, while unknown agents account for the remaining 62 million illnesses, 265,000 hospitalizations, and 3,200 deaths. Overall, foodborne diseases appear to cause more illnesses but fewer deaths than previously estimated.
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.
The germicidal efficacy of three common sanitizers (quaternary ammonium compound, iodophor, and chlorine) on Listeria ( L. monocytogenes V7, L. monocytogenes Scott A, L. ivanovii , and L. innocua ) was studied using the suspension test method at various exposure temperature (2-25°C) and times (0.5-1.5 min). The quaternary ammonium compound, iodophor, and chlorine solutions were prepared with sterile deionized water at concentrations of 25-200 ppm, 12.5-50 ppm, and 25-200 ppm, respectively. All three sanitizers were effective (>5.0-log reduction in CFU/ml in 30 s) against Listeria at 25°C regardless of their concentrations. The quaternary ammonium compound at 100-200 ppm and chlorine at 25-200 ppm inactivated a comparable number of Listeria cells at 2°C as they inactivated at 25°C (i.e., cold temperature did not have any visible effect on the efficacy of the sanitizers). However, the efficacy of the quaternary ammonium compound and of the iodophor at 50 ppm and lower concentrations decreased considerable as the exposure temperature decreased, yet the adverse effect of the cold temperature on the efficacy of the sanitizers was reversed via increasing the exposure time. At cold temperatures, L. monocytogenes V7 and L. innocua were inactivated by the quaternary ammonium compound to a lesser degree than L. monocytogenes Scott A and L. ivanovii .
It's a wonder we all don't get sick more often. After all, food safety is far more complex than simply remembering to clean the kitchen counter after you prepare your Thanksgiving turkey. Contaminants can creep into the food supply at many different points. They can get in early on, as with veterinary drugs or sewage and toxins picked up from water by seafood. Produce may carry pesticides or naturally occurring toxicants such as solanine in potatoes. Food can be contaminated during transit—if a truck isn't cleaned properly between loads, for example. Food handlers and equipment all along the chain can introduce contaminants, ranging from hair to metal filings to bacteria. And consumers themselves may not cook or store the food appropriately to limit the growth of or to kill microorganisms. Of all these possible sources of food contamination, microorganisms are "generally recognized to be the biggest problem," says Myron Solberg, director of the Center for ...
Cut lettuce dip-inoculated with Escherichia coli O157:H7 and Salmonella was treated with alkaline electrolyzed water (AlEW) at 20°C for 5min, and subsequently washed with acidic electrolyzed water (AcEW) at 20°C for 5min. Pre-treatment with AlEW resulted in an approximate 1.8log10cfu/g reduction of microbial populations, which was significantly (p⩽0.05) greater than microbial reductions resulting from other pre-treatment solutions, including distilled water and AcEW. Repeated AcEW treatment did not show a significant bacterial reduction. Mildly heated (50°C) sanitizers were compared with normal (20°C) or chilled (4°C) sanitizers for their bactericidal effect. Mildly heated AcEW and chlorinated water (200ppm free available chlorine) with a treatment period of 1 or 5min produced equal reductions of pathogenic bacteria of 3log10 and 4log10cfu/g, respectively. The procedure of treating with mildly heated AlEW for 5min, and subsequent washing with chilled (4°C) AcEW for period of 1 or 5min resulted in 3–4log10cfu/g reductions of both the pathogenic bacterial counts on lettuce. Extending the mild heat pre-treatment time increased the bactericidal effect more than that observed from the subsequent washing time with chilled AcEW. The appearance of the mildly heated lettuce was not deteriorated after the treatment. In this study, we have illustrated the efficacious application of AlEW as a pre-wash agent, and the effective combined use of AlEW and AcEW.
The presence of numerous genera of spoilage bacteria, yeasts and molds, and an occasional pathogen on fresh produce has been recognized for many years. Several outbreaks of human gastroenteritis have been linked to the consumption of contaminated fresh vegetables and, to a lesser extent, fruits. Salads containing raw vegetables have been identified as vehicles of traveler's diarrhea, an illness sometimes experienced by visitors to developing countries. Enterotoxigenic Escherichia coli is the most common cause of this illness. Enterohemorrhagic E. coli, specifically serotype O157:H7, has been implicated as the causative agent in an outbreak of gastroenteritis resulting from the consumption of cantaloupes. Outbreaks of salmonellosis in humans have been attributed to consumption of contaminated tomatoes, mustard cress, bean sprouts, cantaloupe, and watermelon. An onion-associated outbreak of Shigella flexneri gastroenteritis has recently been reported in the United States. Outbreaks of human listeriosis have been epidemiologically linked to the consumption of fresh cabbage and lettuce. Gastrointestinal illness caused by the consumption of raw vegetable seed sprouts contaminated by Bacillus cereus has been documented. The ability of Aeromonas hydrophila and Aeromonas sobria to produce several virulence factors has been documented and their fairly common occurrence in water raises concern over public health risks that may be associated with the consumption of salad vegetables, although their role as agents in foodborne illness has not been fully confirmed. Viruses are not likely to grow on contaminated vegetables and fruits but can survive long enough to cause life-threatening illness in humans. An increased per capita consumption of fresh and lightly processed produce in the United States and other countries, coupled with an increase in importation of produce to these countries from regions where standards for growing and handling produce may be compromised, has resulted in heightened interest in outbreaks of human gastroenteritis that may be attributed to contaminated fresh produce, particularly salad vegetables. Likewise methods of handling, processing, packaging, and distribution of fresh produce on a regional or local scale within countries are receiving attention in terms of identifying and controlling microbiological hazards. Hazard analysis critical control point (HACCP) programs are being developed in an effort to minimize the risk of illness associated with consumption of fresh produce. Examples of pathogenic microorganisms associated with fresh produce as well as procedures that can be used to reduce their incidence at the point of consumption are discussed.
The efficiencies of potassium persulphate, isopropanol, hydrogen peroxide and peracetic acid, quaternary ammonium compound, hypochlorite, sodium dichloroisocyanurate, ethanol and phenol derivatives, tertiary alkylamines and dimethyl alamine betaine-based disinfectants and a hypochlorite-based disinfecting cleaning agent were evaluated against eight Listeria monocytogenes strains representing three different ribotypes. All the disinfectants were effective in a suspension test with an exposure time of 30 s at the lowest concentrations recommended by the manufacturer. The efficiencies on surfaces were reduced. However, on clean surfaces all the agents were considered effective when the exposure time was 5 min and the concentration was the average recommended by the manufacturer. Five of nine disinfectants and the disinfecting cleaning agent were considered effective in soiled conditions in the surface test. The most efficient agent was isopropanol-based and the least effective was the disinfectant containing tertiary alkylamine and dimethyl alamine betaine. Differences in bactericidal efficiencies of disinfectants against different L. monocytogenes strains on meat soiled surfaces were found.
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.
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.
Experiments were conducted to determine the effectiveness of acidic (EOA) or basic electrolyzed oxidizing (EOB) water, alone or in combination, on ready-to-eat (RTE) meats to reduce Listeria monocytogenes (LM). Frankfurters or ham surfaces were experimentally inoculated with LM and subjected to dipping or spraying treatments (25 or 4°C for up to 30 min) with EOA, EOB, and other food grade compounds. LM was reduced the greatest when frankfurters were treated with EOA and dipped at 25°C for 15 min. A combination spray application of EOB/EOA also resulted in a slight reduction of LM on frankfurters and ham. However, reductions greater than 1log CFU/g were not observed for the duration of the study. Even with a prolonged contact time, treatments with EOA or EOB were not enough to meet regulatory requirements for control of LM on RTE meats. As such, additional studies to identify food grade antimicrobials to control the pathogen on RTE meats are warranted.
The efficiency of slightly acidic electrolyzed water (SAEW) at different temperatures (4, 20 and 45 degrees C) for inactivation of Salmonella enteritidis and it on the surface of shell eggs was evaluated. The bactericidal activity of SAEW, sodium hypochlorite solution (NaClO) and acidic electrolyzed water (AEW) to inactivate S. enteritidis was also compared. SAEW with a pH value of 6.0-6.5 used was generated by the electrolysis of a dilute hydrochloric acid (2.4 mM) in a chamber without a membrane. Although the pH value of SAEW was greatly higher than that of AEW (pH2.6-2.7), SAEW had a comparative powerful bactericidal activity at the same available chlorine concentrations. The efficiency of SAEW for inactivation of pure S. enteritidis cultures increased with increasing the available chlorine concentration and treatment time at the three different temperatures. The S. enteritidis counts decreased to less than 1.0 log(10) CFU/ml at available chlorine of 2 mg/l and 100% inactivation (reduction of 8.2 log(10) CFU/ml) was resulted in using SAEW with available chlorine more than 4 mg/l at 4, 20 and 45 degrees C after 2 min treatment, whereas no reduction was observed in the control samples. Moreover, SAEW was also effective for inactivating the S. enteritidis inoculated on the surface of shell eggs. A reduction of 6.5 log(10) CFU/g of S. enteritidis on shell eggs was achieved by SAEW containing 15 mg/l available chlorine for 3 min, but only a reduction of 0.9-1.2 log(10) CFU/g for the control samples. No survival of S. enteritidis was recovered in waste wash SAEW after treatment. The findings of this study indicate that SAEW may be a promising disinfectant agent for the shell egg washing processing without environmental pollution.
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.
This study investigates the properties of electrolyzed oxidizing (EO) water for the inactivation of pathogen and to evaluate the chemically modified solutions possessing properties similar to EO water in killing Escherichia coli O157:H7. A five-strain cocktail (10(10) CFU/ml) of E. coli O157:H7 was subjected to deionized water (control), EO water with 10 mg/liter residual chlorine (J.A.W-EO water), EO water with 56 mg/liter residual chlorine (ROX-EO water), and chemically modified solutions. Inactivation (8.88 log10 CFU/ml reduction) of E. coli O157:H7 occurred within 30 s after application of EO water and chemically modified solutions containing chlorine and 1% bromine. Iron was added to EO or chemically modified solutions to reduce oxidation-reduction potential (ORP) readings and neutralizing buffer was added to neutralize chlorine. J.A.W-EO water with 100 mg/liter iron, acetic acid solution, and chemically modified solutions containing neutralizing buffer or 100 mg/liter iron were ineffective in reducing the bacteria population. ROX-EO water with 100 mg/liter iron was the only solution still effective in inactivation of E. coli O157:H7 and having high ORP readings regardless of residual chlorine. These results suggest that it is possible to simulate EO water by chemically modifying deionized water and ORP of the solution may be the primary factor affecting microbial inactivation.
This study was undertaken to evaluate the efficacy of electrolyzed oxidizing (EO) and chemically modified water with properties similar to the EO water for inactivation of different types of foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes and Bacillus cereus). A five-strain cocktail of each microorganism was exposed to deionized water (control), EO water and chemically modified water. To evaluate the effect of individual properties (pH, oxidation-reduction potential (ORP) and residual chlorine) of treatment solutions on microbial inactivation, iron was added to reduce ORP readings and neutralizing buffer was added to neutralize chlorine. Inactivation of E. coli O157:H7 occurred within 30 s after application of JAW EO water with 10 mg/l residual chlorine and chemically modified solutions containing 13 mg/l residual chlorine. Inactivation of Gram-positive and -negative microorganisms occurred within 10 s after application of ROX EO water with 56 mg/l residual chlorine and chemically modified solutions containing 60 mg/l residual chlorine. B. cereus was more resistant to the treatments than E. coli O157:H7 and L. monocytogenes and only 3 log10 reductions were achieved after 10 s of ROX EO water treatment. B. cereus spores were the most resistant pathogen. However, more than 3 log10 reductions were achieved with 120-s EO water treatment.
The chlorine loss of electrolyzed oxidizing (EO) water was examined during storage under different light, agitation, and packaging conditions. The chlorine loss of pH-adjusted EO water was also examined. Under open conditions, the chlorine loss through evaporation followed first-order kinetics. The rate of chlorine loss was increased about 5-fold with agitation, but it was not significantly affected by diffused light. Under closed conditions, the chlorine loss did not follow first-order kinetics, because the primary mechanism of chlorine loss may be self-decomposition of chlorine species rather than chlorine evaporation. The effect of diffused light was more significant compared to agitation after two months of storage under closed conditions. The chlorine loss of EO water and commercial chlorinated water decreased dramatically with the increase of pH from the acidic (pH 2.5) to the alkaline (pH 9.0) region.
The effectiveness of electrolyzed (EO) water for killing Campylobacter jejuni on poultry was evaluated. Complete inactivation of C. jejuni in pure culture occurred within 10 s after exposure to EO or chlorinated water, both of which contained 50 mg/l of residual chlorine. A strong bactericidal activity was also observed on the diluted EO water (containing 25 mg/l of residual chlorine) and the mean population of C. jejuni was reduced to less than 10 CFU/ml (detected only by enrichment for 48 h) after 10-s treatment. The diluted chlorine water (25 mg/l residual chlorine) was less effective than the diluted EO water for inactivation of C. jejuni. EO water was further evaluated for its effectiveness in reducing C. jejuni on chicken during washing. EO water treatment was equally effective as chlorinated water and both achieved reduction of C. jejuni by about 3 log10 CFU/g on chicken, whereas deionized water (control) treatment resulted in only 1 log10 CFU/g reduction. No viable cells of C. jejuni were recovered in EO and chlorinated water after washing treatment, whereas high populations of C. jejuni (4 log10 CFU/ml) were recovered in the wash solution after the control treatment. Our study demonstrated that EO water was very effective not only in reducing the populations of C. jejuni on chicken, but also could prevent cross-contamination of processing environments.
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.
Electrolyzed oxidizing (EO) water has proved to be effective against foodborne pathogens attached to cutting boards and poultry surfaces and against spoilage organisms on vegetables; however, its levels of effectiveness against Listeria monocytogenes and Salmonella Typhimurium in cell suspensions have not been compared with those of other treatments. In this study, the oxidation reduction potentials (ORPs), chlorine concentrations, and pHs of acidic and basic EO water were monitored for 3 days at 4 and 25 degrees C after generation. There were no differences between the pHs or ORPs of acidic and basic EO waters stored at 4 or 25 degrees C. However, the free chlorine concentration in acidic EO water stored at 4 degrees C increased after 24 h. In contrast, the free chlorine concentration in acidic EO water stored at 25 degrees C decreased after one day. Cell suspensions of Salmonella Typhimurium and L. monocytogenes were treated with distilled water, chlorinated water (20 ppm), acidified chlorinated water (20 ppm, 4.5 pH), acidic EO water (EOA), basic EO water (EOB), or acidic EO water that was "aged" at 4 degrees C for 24 h (AEOA) for up to 15 min at either 4 or 25 degrees C. The largest reductions observed were those following treatments carried out at 25 degrees C. EOA and AEOA treatments at both temperatures significantly reduced Salmonella Typhimurium populations by > 8 log10 CFU/ml. EOA and AEOA treatments effectively reduced L. monocytogenes populations by > 8 log10 CFU/ml at 25degrees C. These results demonstrate the stability of EO water under different conditions and that EO water effectively reduced Salmonella Typhimurium and L. monocytogenes populations in cell suspensions.
The influence of bacterial inoculation methods on the efficacy of sanitizers against pathogens was examined. Dip and spot inoculation methods were employed in this study to evaluate the effectiveness of acidic electrolyzed water (AcEW) and chlorinated water (200 ppm free available chlorine) against Escherichia coli O157:H7 and Salmonella spp. Ten pieces of lettuce leaf (5 by 5 cm) were inoculated by each method then immersed in 1.5 liters of AcEW, chlorinated water, or sterile distilled water for 1 min with agitation (150 rpm) at room temperature. The outer (abaxial) and inner (adaxial) surfaces of the lettuce leaf were distinguished in the spot inoculation. Initial inoculated pathogen population was in the range 7.3 to 7.8 log CFU/g. Treatment with AcEW and chlorinated water resulted in a 1 log CFU/g or less reduction of E. coli O157:H7 and Salmonella populations inoculated with the dip method. Spot inoculation of the inner surface of the lettuce leaf with AcEW and chlorinated water reduced the number of E. coli O157:H7 and Salmonella by approximately 2.7 and 2.5 log CFU/g, respectively. Spot inoculation of the outer surface of the lettuce leaf with both sanitizers resulted in approximately 4.6 and 4.4 log CFU/g reductions of E. coli O157:H7 and Salmonella, respectively. The influence of inoculation population size was also examined. Each sanitizer could not completely eliminate the pathogens when E. coli O157:H7 and Salmonella cells inoculated on the lettuce were of low population size (10(3) to 10(4) CFU/g), regardless of the inoculation technique.
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.
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.
Consumption of minimally-processed, or fresh-cut, fruit and vegetables has rapidly increased in recent years, but there have also been several reported outbreaks associated with the consumption of these products. Sodium hypochlorite is currently the most widespread disinfectant used by fresh-cut industries. Neutral electrolyzed water (NEW) is a novel disinfection system that could represent an alternative to sodium hypochlorite. The aim of the study was to determine whether NEW could replace sodium hypochlorite in the fresh-cut produce industry. The effects of NEW, applied in different concentrations, at different treatment temperatures and for different times, in the reduction of the foodborne pathogens Salmonella, Listeria monocytogenes and Escherichia coli O157:H7 and against the spoilage bacterium Erwinia carotovora were tested in lettuce. Lettuce was artificially inoculated by dipping it in a suspension of the studied pathogens at 10(8), 10(7) or 10(5) cfu ml(-1), depending on the assay. The NEW treatment was always compared with washing with deionized water and with a standard hypochlorite treatment. The effect of inoculum size was also studied. Finally, the effect of NEW on the indigenous microbiota of different packaged fresh-cut products was also determined. The bactericidal activity of diluted NEW (containing approximately 50 ppm of free chlorine, pH 8.60) against E. coli O157:H7, Salmonella, L. innocua and E. carotovora on lettuce was similar to that of chlorinated water (120 ppm of free chlorine) with reductions of 1-2 log units. There were generally no significant differences when treating lettuce with NEW for 1 and 3 min. Neither inoculation dose (10(7) or 10(5) cfu ml(-1)) influenced the bacterial reduction achieved. Treating fresh-cut lettuce, carrot, endive, corn salad and 'Four seasons' salad with NEW 1:5 (containing about 50 ppm of free chlorine) was equally effective as applying chlorinated water at 120 ppm. Microbial reduction depended on the vegetable tested: NEW and sodium hypochlorite treatments were more effective on carrot and endive than on iceberg lettuce, 'Four seasons' salad and corn salad. The reductions of indigenous microbiota were smaller than those obtained with the artificially inoculated bacteria tested (0.5-1.2 log reduction). NEW seems to be a promising disinfection method as it would allow to reduce the amount of free chlorine used for the disinfection of fresh-cut produce by the food industry, as the same microbial reduction as sodium hypochlorite is obtained. This would constitute a safer, 'in situ', and easier to handle way of ensuring food safety.
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