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Efficacy of neutral electrolyzed water (NEW) for reducing microbial contamination on minimally-processed vegetables
Abstract
Consumption of minimally-processed, or fresh-cut, fruit and vegetables has rapidly increased in recent years, but there have also been several reported outbreaks associated with the consumption of these products. Sodium hypochlorite is currently the most widespread disinfectant used by fresh-cut industries. Neutral electrolyzed water (NEW) is a novel disinfection system that could represent an alternative to sodium hypochlorite. The aim of the study was to determine whether NEW could replace sodium hypochlorite in the fresh-cut produce industry. The effects of NEW, applied in different concentrations, at different treatment temperatures and for different times, in the reduction of the foodborne pathogens Salmonella, Listeria monocytogenes and Escherichia coli O157:H7 and against the spoilage bacterium Erwinia carotovora were tested in lettuce. Lettuce was artificially inoculated by dipping it in a suspension of the studied pathogens at 10(8), 10(7) or 10(5) cfu ml(-1), depending on the assay. The NEW treatment was always compared with washing with deionized water and with a standard hypochlorite treatment. The effect of inoculum size was also studied. Finally, the effect of NEW on the indigenous microbiota of different packaged fresh-cut products was also determined. The bactericidal activity of diluted NEW (containing approximately 50 ppm of free chlorine, pH 8.60) against E. coli O157:H7, Salmonella, L. innocua and E. carotovora on lettuce was similar to that of chlorinated water (120 ppm of free chlorine) with reductions of 1-2 log units. There were generally no significant differences when treating lettuce with NEW for 1 and 3 min. Neither inoculation dose (10(7) or 10(5) cfu ml(-1)) influenced the bacterial reduction achieved. Treating fresh-cut lettuce, carrot, endive, corn salad and 'Four seasons' salad with NEW 1:5 (containing about 50 ppm of free chlorine) was equally effective as applying chlorinated water at 120 ppm. Microbial reduction depended on the vegetable tested: NEW and sodium hypochlorite treatments were more effective on carrot and endive than on iceberg lettuce, 'Four seasons' salad and corn salad. The reductions of indigenous microbiota were smaller than those obtained with the artificially inoculated bacteria tested (0.5-1.2 log reduction). NEW seems to be a promising disinfection method as it would allow to reduce the amount of free chlorine used for the disinfection of fresh-cut produce by the food industry, as the same microbial reduction as sodium hypochlorite is obtained. This would constitute a safer, 'in situ', and easier to handle way of ensuring food safety.
... The use of electrolyzed water is the main physicochemical technology available for the treatment of minimally processed foods ( Abadias, Usall, Oliveira, Alegre & Viñas, 2008 ;Rahman, Khan & Oh, 2016 ). This technique can be used to replace chemical treatments in the sanitization stages, uses only sodium chloride (NaCl) in its production, and is widely used for disinfecting vegetables after slicing and before packaging ( Abadias, Usall, Oliveira, Alegre & Viñas, 2008 ;Graça, Abadias, Salazar & Nunes, 2011 ). ...
... The use of electrolyzed water is the main physicochemical technology available for the treatment of minimally processed foods ( Abadias, Usall, Oliveira, Alegre & Viñas, 2008 ;Rahman, Khan & Oh, 2016 ). This technique can be used to replace chemical treatments in the sanitization stages, uses only sodium chloride (NaCl) in its production, and is widely used for disinfecting vegetables after slicing and before packaging ( Abadias, Usall, Oliveira, Alegre & Viñas, 2008 ;Graça, Abadias, Salazar & Nunes, 2011 ). The principle of this technology involves the electrolysis of dilute NaCl solutions as shown in Fig. 2 , in which the anodes and cathodes can be separated or not by a diaphragm. ...
... Neutral electrolyzed water is the most effective alternative to decontaminate produce without causing sensory losses due to its greater stability ( Cui, Shang, Shi, Xin & Cao, 2009 ;Deza, Araujo & Garrido, 2003 ). The antimicrobial efficacy of this method is similar to those of chemical treatments, such as treatment with sodium hypochlorite, and is safer, as it reduces the amount of free chlorine present in minimally processed products after disinfection ( Abadias, Usall, Oliveira, Alegre & Viñas, 2008 ). It does have some drawbacks, such as the reduction of antimicrobial activity over time due to the presence of organic matter that reduces the concentration of active chlorine, requiring the continuous replacement of the NaCl source in the electrolyzed water. ...
In recent years, minimally processed fruits and vegetables have gained widespread consumer attention due to the need for a convenient yet healthy diet. As several factors can affect the shelf life of minimally processed products, it is essential to use preservation technologies that maintain the freshness of fruits and vegetables ensuring consumer health. In the second part of this review, the main physical preservation methods including heat treatments, refrigeration, irradiation, high pressure, ultraviolet radiation, and electrolyzed water are discussed in terms of their advantages, disadvantages, and applications. Advances in packaging for minimally processed products are also explored, such as active and intelligent packaging, edible films and coatings, and vacuum packaging. Defining the operational parameters related to treatment time and dose/intensity appropriate is one of the greatest difficulties in the application of physical methods. Therefore, these factors must be carefully evaluated, as must the sustainability and economic viability of each method.
... As shown in Figure 7, no bactericidal effect against each microorganism was observed, even after 5 min of treatment time. This result suggests the potential risk that alkaline sanitizers, such as sodium bicarbonate solution [72] and neutral electrolyzed water (NEW) [73], are ineffective to these microorganisms. However, if the alkaline sanitizers contain other biocidal reagents, the bactericidal effect should be expected because these microorganisms were inactivated by 2 and 5 ppm sodium hypochlorite solutions, with pH values of 7.68 and 8.19, respectively (Figure 4). ...
... However, if the alkaline sanitizers contain other biocidal reagents, the bactericidal effect should be expected because these microorganisms were inactivated by 2 and 5 ppm sodium hypochlorite solutions, with pH values of 7.68 and 8.19, respectively (Figure 4). NEW seems to be an effective sanitizer against these microorganisms because it contains HOCl and − OCl [73]. was observed, even after 5 min of treatment time. ...
... was observed, even after 5 min of treatment time. This result suggests the potential risk that alkaline sanitizers, such as sodium bicarbonate solution [72] and neutral electrolyzed water (NEW) [73], are ineffective to these microorganisms. However, if the alkaline sanitizers contain other biocidal reagents, the bactericidal effect should be expected because these microorganisms were inactivated by 2 and 5 ppm sodium hypochlorite solutions, with pH values of 7.68 and 8.19, respectively (Figure 4). ...
Disinfection and sterilization against cold-tolerant microorganisms are very important for enhancing food safety and hygiene management under refrigeration conditions. We isolated Exiguobacterium sp. and Pantoea sp. from an immersion solution of packed tofu and evaluated their growth properties and sensitivities to various bactericidal methods. These microorganisms were classified as psychrotrophic bacteria, according to their ability to grow at 4 °C, with an optimum growth temperature of 30 °C. Exiguobacterium sp. and Pantoea sp. were more sensitive to heat and sodium hypochlorite than Escherichia coli (E. coli). Exiguobacterium sp. was sensitive to acetic acid and citric acid, while Pantoea sp. was relatively insensitive and E. coli was insensitive to these organic acids. All microorganisms used in this study were resistant to sodium hydroxide solution (pH 8.00). Exiguobacterium sp. showed resistance to ozonated water and UV; therefore, particular attention should be paid to the contamination of this microorganism in food factories. Both Exiguobacterium sp. and Pantoea sp. were inactivated by pulsed electric field (PEF) treatment that did not cause lethal damage to E. coli. The results obtained in this study suggest that the bactericidal methods targeting the fragile cell membrane with high permeability are effective for the inactivation of cold-tolerant microorganisms.
... The utilization of neutral electrolyzed water (NEW), also known as slightly acidic electrolyzed water (SAEW), had been proven to have a similar or better reduction of Salmonella Enteritidis on the surface of eggs than AEW (Cao et al., 2009;Yuan et al., 2022). Although SAEW shows promise, it is still less effective than more traditional sanitizers like chlorine (Abadias et al., 2008;Huang et al., 2020). ...
... other sanitizers based heavily on chlorine, it has not been proven to entirely inactivate foodborne pathogens, including microorganisms present naturally on the surface of foods (Abadias et al., 2008;Li et al., 2022;Yuan et al., 2022). ...
Eggs in the United States are typically washed using chemical sanitizers such as quaternary ammonia (QA) or chlorine. Such treatments generate wash water, which could be potentially hazardous to the environment. A novel, nonthermal sanitization technique for washing shell eggs using cold plasma-activated water (PAW) was investigated in this study. The inactivation efficacy of PAW on Klebsiella michiganensis and the impact of PAW on the cuticle of the eggshell and shell strength were tested in comparison to QA. Washing inoculated eggs with PAW and QA achieved a similar microbial reduction (>5.28 log CFU/egg). Colorimetric analysis showed that ∆E-value for PAW-treated eggs was significantly lower than QA-treated eggs, suggesting higher cuticle coverage in eggs treated with PAW. The texture analysis to test for shell egg strength indicated that washing eggs with PAW did not affect the structural integrity of the eggshell when compared to eggs washed with QA. According to this study, PAW has the potential as an alternative to commercial sanitizers like QA in the egg-washing industry. PAW does not detrimentally impact shell strength or cuticle coverage and provides similar microbial reduction efficacy.
... EW is considered environmental-friendly sanitizer because it is generated from dilute salt and water, cause less corrosion to surface of production plant and eliminate the effect to human body. [6]- [8] This paper serves as a systematic review on the recent progress of the application of EW as a sanitizer in food industry. It reviewed the efficacy of EW on major foodborne pathogens and foodborne spoilage microorganisms, the antimicrobial mechanism of EW on microorganisms, factors that affect the antimicrobial efficacy of EW application and the effect of EW on food quality. ...
... Its neutral pH may pose less negative effect on human health and environment hence it receives many interest in recent years. [6] Low concentration Electrolyzed Water. (ACC < 10 ppm, LcEW) LcEW is often produced by electrolyzing a diluted NaCl solution with water in an EW generator that has no separate membrane. ...
... Electrolyte water is a relatively novel treatment that appears to be highly effective against a wide range of foodborne pathogens attached to surfaces (Venkitanarayanan et al., 1999)meat and poultry and fresh produce spoilage microorganisms ( Park et al., 2004). Another study conducted by (Abadias et al., 2008) showed that neutral electrolyte water exhibited a similar antibacterial effect as chlorine water at low-level chlorine content (free chlorine content). The neutral electrolyte water solution disinfection method (pH 8.6 and ACC of 50 mg/L) reduced the level of foodborne pathogens (E. ...
Electrolyte water is a powerful antibacterial and antibiofilm agent. The aim of the study was to determine the bacterial time-kill kinetics of electrolyte water. Bacteria were isolated from laboratory benches and identified by Gram staining and biochemical tests. Each isolate was subjected to 15, 30 and 45min exposure in electrolyte water, 0.35% hypochlorite, and sterilized water. Exposed isolates were subcultured on agar media to check for their viability. The bacteria isolates were Staphylococcus aureus, Staphylococcus epidermidis, Bacillus sp., Klebsiella sp.,
Salmonella typhi, Citrobacter freundi, Citrobacter sp., Citrobacter koseri. Electrolyte water inhibited the growth of all bacteria species isolated under 15 minutes except Staphylococcus
aureus and Bacillus sp. Hypochlorite inhibited all bacteria species isolated under 15 minutes except Bacillus sp., Salmonella typhi, and Staphylococcus epidermidis. Sterilized water did not
inhibit any of the bacteria species after 45 minutes of exposure. Electrolyte water may be a good agent for disinfection of laboratory benches and hospital items as part of infection prevention and control.
... Exposing water to electric or magnetic fields affects the water components, including the mineral content and microbial count, and the effects depend upon the strength of the electric/magnetic field and the exposure time. From this perspective, the most significant advantage of using ionized water to inactivate bacteria is the lack of the need of chemicals [43]. According to the results of Table 5, the use of ionized alkaline water given to chicks had a beneficial influence on their intestinal health by enhancing gut integrity and modulating the gut microflora by reducing the colonization of intestinal pathogenic bacteria and promoting competitive exclusion. ...
Ionized drinking water can improve the health and productivity of broiler chicks.
... On the other hand, chlorination of SSW alone resulted in a more substantial improvement in growth rate and productivity compared to both autoclaving and filtration-based pre-treatment methods. Chlorination effectively reduces microbial contaminants while better preserving the essential nutrients in the seawater [27,28]. This method likely maintains a balance between sterilization and nutrient availability, creating a more favourable environment for microalgae growth. ...
Edible seaweeds have gained significant interest among the nutraceutical industries due to their rich content of amino acids, fatty acids, and minerals. The tank cultivation of edible seaweed like Ulva sp. generates a significant amount of spent seawater, which must either be reused or treated for safe discharge into coastal waters. This study aims to utilize spent seawater from Ulva sp. grown tanks for the production of marine microalgal biomass, focusing on the extraction of high-value lutein and protein. Accordingly, three major pre-treatment methods—autoclaving, filtration, and chlorination—were performed on spent seawater, both with and without medium supplementation, followed by the cultivation of marine Chlorella sp. 1151 as a model microalga. Among the treatment methods, spent seawater either sterilized by autoclave or chlorination with medium addition resulted in higher biomass (0.91–1.03 g L⁻¹), lutein (1.10–1.88 mg g⁻¹), and protein (64.86 – 68.83 mg g⁻¹) yields, which were almost comparable to those obtained with fresh seawater supplemented with medium. Chlorella sp. 1151 efficiently utilized nitrate and phosphate by 95–97% in the spent seawater for the optimal experimental combinations as stated above. Further, analysis of heavy metals including Co, Cu, Fe, Mn, Zn, Ba, Ni, Mo, Pb, Cr, and Cd in the cultivated spent seawater were well below the permissible limits for safe discharge. This study demonstrates the novel approach of repurposing spent seawater from seaweed cultivation for the production of marine microalgal biomass- based lutein and protein.
... The microbiological effects of the addition of different concentrations of WL to peach and grape juices were assessed following Ortiz-Solá et al. [25]. The bacterial strains used in this work included a cocktail of 5 strains of Listeria monocytogenes: serovar 1a (CECT 4031), serovar 3a (CECT 933), serovar 4d (CECT 940), serovar 4b (CECT 4032), and serovar 1/2a, which was previously isolated in our laboratory from a fresh-cut lettuce sample [26]. The yeast Saccharomyces cerevisiae WDCM00058 was used as a model for spoilage microorganisms. ...
The valorization of agri-food products not only represents important economic and environmental benefits but can also be a source of potentially profitable, functional, and safe ingredients. This study aimed to valorize peach fruit and wine lees (WL) by producing functional juice. WL were incorporated at different concentrations (1.5 and 2%; w:w) in unpasteurized peach and grape juice and subsequently stored under refrigeration (5 °C). The antimicrobial activity of WL in peach and grape juices was assessed against Listeria monocytogenes and Saccharomyces cerevisiae as well as physicochemical, nutritional microbiological, and sensory acceptability. The maximum addition of WL to the juice (2%) showed a significant inhibitory effect against L. monocytogenes (4-log reduction) and increased the content of total soluble solids (TSS) (10%), total polyphenol content (TPC) (75%), and total antioxidant activity (AOX) (86%). During storage, AOX, TPC, TSS, pH, and titratable acidity (TA) remained stable. A significant correlation was observed between TPC and AOX. Total mesophilic aerobic bacteria and yeast counts increased during storage. Fifty-seven percent of tasters (n = 26) rated the functional juice positively. Thus, these agri-food products could be useful for producing functional juices with a longer shelf life, contributing to their valorization.
... In the present study, C. sakazakii significantly decreased with an increase in SAEW concentrations. In addition, due to its slightly acidic pH, SAEW does not corrode processing equipment or irritate producers' hands as severely as strong acidic electrolyzed water (Abadias et al., 2008;Issa-Zacharia et al., 2010). ...
Powdered infant formula (PIF) is prone to Cronobacter sakazakii (C. sakazakii) contamination, which can result in infections that endanger the lives of newborns and infants. Slightly acidic electrolytic water (SAEW) has shown antibacterial effects on a variety of foodborne pathogens and has a wide applicability in the food industry. Here, the antibacterial activity of SAEW against C. sakazakii and its use as a disinfectant on contact surfaces with high infection transmission risk were investigated. The inactivation of SAEW on C. sakazakii was positively correlated to the SAEW concentration and treatment time. The antibacterial effect of SAEW was achieved by decreasing the intracellular adenosine triphosphate (ATP), K⁺, protein, and DNA contents of C. sakazakii, reducing the intracellular pH (pHin) and destroying the cell morphology, which led to inactivation of C. sakazakii ultimately. To test the applicability of this study, the results showed that approximately 10³ CFU/cm² of C. sakazakii were successfully inactivated on stainless steel and rubber surfaces after a 30 mg/L SAEW treatment for 20 s. These results indicate the antibacterial mechanism and potential application of SAEW against C. sakazakii, as well as a new strategy for the prevention and control of C. sakazakii on stainless steel and rubber surfaces.
... In the 1990s alone, 12% of illnesses were food associated [19]. Examples of this are infections with Listeria monocytogenes and Escherichia coli, which can be found on lettuce too [18,20,21]. ...
Foods consumed raw, such as lettuce, can host food-borne human-pathogenic bacteria. In the worst-case, these diseases cause to death. To limit illness and industrial losses, one innovative sanitation method is non-thermal plasma, which offers an extremely efficient reduction of living microbial biomass. Unfortunately, the total viable count (TVC), one of the most common methods for quantifying antimicrobial effects, provides no detailed insights into the composition of the surviving microbial community after treatment. To address this information gap, different special agars were used to investigate the reduction efficiency of plasma-treated water (PTW) on different native cultivable microorganisms. All tested cultivable microbial groups were reduced using PTW. Gram-negative bacteria showed a reduction of 3.81 log10, and Gram-positive bacteria showed a reduction of 3.49 log10. Fungi were reduced by 3.89 log10. These results were further validated using a live/dead assay. MALDI-ToF (matrix-assisted laser-desorption-ionization time-of-flight)-based determination was used for a diversified overview. The results demonstrated that Gram-negative bacteria were strongly reduced. Interestingly, Gram-positive bacteria and fungi were reduced by nearly equal amounts, but could still recover from PTW treatment. MALDI-ToF mainly identified Pseudomonas spp. and groups of Bacillus on the tested lettuce. These results indicate that the PTW treatment could efficiently achieve a ubiquitous, spectrum-wide reduction of microbial life.
... NaOCl is commonly known as powerful disinfectant, and its remedies successfully lessen the contagious potential of a variety of viruses, bacteria, and fungus (Peeters et al., 2008). Sodium hypochlorite has effective antimicrobial mechanisms, tissue dissolution capacity and showed a biological compatibility in less concentrated solutions (Abadias et al., 2008;Gerba and Denise, 2007). The study aimed to investigate the action of sodium hypochlorite against snails, B. alexandrina the intermediate host of S. mansoni, and elucidate its role as a control agent against B. alexandrina snail's immunological and hepato-endocrine alterations with in-silico molecular docking. ...
Schistosomiasis is a tropical disease that widely neglected. Schistosoma mansoni reproduce asexually within the freshwater snail, Biomphlaria alexandrina. Sodium hypochlorite (NaOCl) is a widely used disinfectant, so its effect against gainst B. alexandrina snails was evaluated. The present results showed that NaOCl has a molluscicidal activity against adult B. alexandrina snails at LC50 1.25 ppm. Hemocytes displayed varied morphological forms after being exposed to the LC10 and LC25 concentrations of NaOCl in B. alexandrina snails, and the phagocytic index of B. alexandrina snail's hemocytes significantly increased. The phagocytic potency of exposed hemocytes to charcoal showed ruptured plasma membrane, engulfed particles, vacuolation in the cytoplasm and degeneration of nuclei. When B. alexandrina snails were treated with sublethal concentrations of NaOCl, transaminases (AST & ALT), alkaline and acid phosphatase activities were significantly increased. In contrast, the total protein, albumin concentrations, Testosterone (T) and 17β Estradiol (E) showed a significant decrease (p ≤ 0.05) as compared to the control groups. The molecular docking interaction showed high efficiency for the ligand, NaOCl against the receptor binding sites of the acid phosphatase, alanine aminotransferase, estrogen and testosterone. The present results showed that NaOCl could be used as an effective molluscicide against B. alexandrina snails but more attention should be paid to investigate the side effects on the non-target organisms living in the freshwater environment.
... Pathogens causing these infections are, among others, Listeria monocytogenes, Campylobacter spp. and Escherichia coli, which could lead to illnesses resulting in hospitalization and death (Abadias et al., 2008;Williams et al., 2013;McManamon et al., 2017;Lee and Yoon 2021). Most of the time, animal-based food are the primary vectors for illness, but vegetables could also be potential carriers of pathogens (Heredia and García 2018;Lee and Yoon 2021). ...
Plant-based foods like lettuce are an important part of the human diet and worldwide industry. On a global scale, the number of food-associated illnesses increased in the last decades. Conventional lettuce sanitation methods include cleaning either with tap or chloritized water. Beside these water-consuming strategies, physical plasma is an innovative and effective possibility for food sanitation. Recent studies with plasma-treated water showed an effective reduction of the microbial load. Plasma-processed air (PPA) is another great opportunity to reduce the microbial load and save water. To test the efficiency of PPA, the surface microbiome of treated lettuce was analyzed via proliferation assays with special agars, live/dead assays and tests for respiratory activity of the microorganisms. PPA showed a reduction of the colony forming units (CFU/mL) on all tested microbial groups (Gram-negative and Gram-positive bacteria, yeasts and molds). These results were supported by the live/dead assay. For further insights, the PPA-ingredients were detected with Fourier Transformation Infrared Spectroscopy (FTIR), which revealed NO2, NO and N2O5 as the main reactive species in the PPA. In the future, PPA could be an outstanding, on-demand sanitation step for higher food safety standards, especially in situations where humidity and high temperature should be avoided.
... When Figure 6 is compared with Figure 5, it can be seen that the FAC 50 mg/L MLEW mist had a statically significant inactivating effect compared with pure water (p < 0.05). In previous studies, the minimum concentration of FAC in neutral electrolyzed water required for a virucidal effect was found to be approximately 40 ppm; this is consistent with the results of the present study [25,38]. In the 10 min after FAC 50mg/L MLEW spraying, the HA titer further declined to 2 1 . ...
Avian influenza virus (AIV) can have a serious impact on both human and animal health. In this study, we used an environmentally controlled chamber and a hemagglutination assay (HA) to evaluate the ability of membrane-less electrolyzed water (MLEW) spraying to inactivate H6N1 AIV aerosol. MLEW was generated by electrolyzing sodium chloride solution, and then sprayed into the chamber at free available chlorine (FAC) concentrations of 50, 100 and 200 mg/L by means of high-pressure air pumping to inactivate airborne H6N1 AIV aerosols individually. The results showed that MLEW spraying effectively neutralized H6N1 AIV aerosol. In addition, the virucidal ability of MLEW increased as the FAC concentration increased. Five minutes after MLEW spraying at an FAC concentration of 200 mg/L, the H6N1 viral HA titer decreased from 24 to 20. Our work provides important new evidence of the value of spraying with MLEW disinfectant to protect against AIV, which may be further applied for indoor decontamination purposes to promote animal and human health.
... Samples were homogenized in a Stomacher 400 circulator blender (Seward Ltd, Worthing, West Sussex, UK) at 230 rpm for 2 minutes. 79,80 To remove particular matter, homogenate was poured into a filter bag with 0.5 mm pores (Seward Ltd, Worthing, West Sussex, UK). Aliquots of filtered homogenate were pipetted into 2 mL microcentrifuge safe-lock tubes (Eppendorf, Fisher Scientific, Pittsburgh, PA) and placed in a −80°C freezer for long-term storage before DNA extraction. ...
Educational Objectives:
1. Introduce the relationship between the gut and the brain and how addiction and alcohol can affect this relationship.
2. Introduce relationships of the gut microbiome with alcohol use and the deleterious effects that heavy alcohol use can have on the healthy gut microbiota.
Faculty: Drs. Lorenzo Leggio and Jennifer Barb.
Planner and Moderator: Dr. Vatsalya.
Credit: 1.5 hours.
On-demand: https://www.accp1.org/Members/.
Tentative audience: Physicians, Physician Assistants, Pharmacist, Advanced Nurse Practitioners
Please register to participate in the Webinar. After the lecture, solving the questions will provide credit to those who are interested in continued education credits. The attached publications are part of the overall curriculum and relevant articles will be helpful in further understanding and solving the questions towards the clinical credit.
Upon completion, you will be able to:
1. Identify the broad characterization of pathology associated with microbiome changes in several neurological conditions;
2. Estimate the correlations of microbial changes in neuro-behavioral statuses like eating disorders and AUD;
3. Explore the influence of alcohol consumption and type of drinking and observe longitudinal-temporal changes in the oral microbiome in newly abstinent individuals undergoing inpatient treatment for AUD.
... In fact, SAHW has been applying in food processing plants' cleaning and sanitizing procedures for several years, which reveals excellent bactericidal activity against a wide range of bacteria within a relatively short time (23,40,54). Because of a near-neutral pH of SAHW, it does not contribute to the corrosion of processing equipment or irritation on hands (1). Another important characteristic of SAHW is a lower residual available chlorine in the production site after disinfection in comparison to other chlorine-based sanitizers (28). ...
Biofilm formation of Listeria monocytogenes in food processing environments cause potential source of cross-contamination to foodstuffs; hence, the control of biofilm is currently addressed to find effective solutions for preventing biofilm formation or eliminating the established one. Forty-five strains of Listeria monocytogenes isolated from Pangasius fish-processing plants were studied for their capability to form a biofilm on 96-well microtiter plate by using the conventional crystal violet staining. Additionally, the inhibitory effect of biofilm formation by food additives including monascus pigment and ε-polylysine was examined. The average OD value showing biofilm mass of all 45 strains L. monocytogenes increased with an increasing temperature and time (p < 0.05). Monascus pigment and ε-polylysine significantly decreased biofilm formation by 80 ± 5.5% and 20 ± 5.9%, respectively, at the tested concentration (p < 0.05) Further, the effects of lysozyme (0.1 mg/mL) alone or in combination with slightly acidic hypochlorous water (SAHW) with 40 mg/L available chlorine or sodium hypochlorite (NaOCl) with 100 mg/L available chlorine against 7-d established biofilm of L. monocytogenes were investigated. The results indicated that slightly acidic hypochlorous water alone exhibited significant antibacterial activity (p < 0.05), decreasing the viable count by 5.2 ± 0.5 log CFU/mL. It seems that sequential treatment of lysozyme and SAHW showed an additional efficacy against biofilm of L. monocytogenes on polystyrene plate surface, reducing 70% of biomass of biofilm and 7.6 ± 0.3 log of biofilm viable cells (p < 0.05). Additionally, SAHW exhibited greater bactericidal activity against viable biofilm cells than NaOCl did. This result reveals that SAHW is a promising disinfectant agent against L. monocytogenes and the potential alternative to NaOCl in practice.
... This intrinsic combination can be successfully exploited to ensure juice stability against spoilage bacterial growth. 33 3.1.3. Titratable Acidity of the Juice. ...
The aim of the present work was to study the feasibility of using electro-activation as a nonthermal treatment to produce stable beetroot juice. Specifically, red beetroot juice was electro-activated under two different reactor configurations by using three electric current intensities (100, 200, and 300 mA) during 120 min. Different parameters of the juice were measured such as the pH, redox potential, juice titratable acidity, Brix degree and total dry matter, color, betalain and polyphenolic contents, and antioxidant capacity of the electro-activated juice. By using the reactor Configuration A in which the targeted juice was electro-activated in the anodic compartment of the used reactor, acidic juice with pH 4 and 5 as well as a redox potential close to +300 mV was obtained. The Brix degree, color, dry matter, and phenolic content were not significantly influenced by this electro-activation. However, the treatment permitted increasing the antioxidant capacity of the juice as measured by the DPPH and ABTS assays. By using the reactor Configuration B in which the targeted beet juice was electro-activated in the cathodic compartment of the used compartment, a juice with an alkaline pH of approximately pH 9 and a reducing redox potential of -697 mV was obtained. With this reactor configuration, the Brix degree and total dry matter were not affected, but the color and total polyphenolic content changed. The betalains and polyphenolic compounds were degraded under the alkaline conditions of this electro-activation treatment, which had a negative consequence on the juice quality by decreasing its antioxidant capacity. In conclusion, this study demonstrated that anodic electro-activation of a beet juice can be technologically feasible since this treatment permitted producing stable juice as well as maintaining the main physico-chemical properties of the juice, enhancing its antioxidant capacity, and keeping the juice color at high level.
... Fruits are a great source of nutrients, dietary fiber, minerals, vitamins and energy and its consumption is linked to reduce the risk of cardiovascular diseases and flabbiness. Fruits also are the rich source of phytochemicals and other phenolic compounds that function as anti-inflammatory agents, antioxidants and phytoestrogen [1]. Intake of vegetables and fruits has been increased as today's society is becoming more concerned about health and role of raw fruits and vegetables for improving and maintaining consumer and human health. ...
Fresh cut fruits and vegetable have gained penetration and popularity since last few years. These fresh cut commodities are in great demand among the consumers as these are ready-to-eat fresh and provide all essential nutrients. The increasing trend in fresh cut produce tends to increase the investment in research and development to address various issues regarding the product supply, refrigeration, packaging technology, processing and shelf life extension. Cutting and peeling causes physical damage to the raw fruit and vegetable that make them more perishable. In these review latest developments that plays the key role in extending the shelf life of the fresh cut are discussed. These technologies help in reducing the microbial load over the fresh cut without much altering the physicochemical properties. Future researches should consider various combined technologies which allow better preservation as well as supplemented with nutritional factors.
... Fresh and minimally processed fresh-cut products are naturally contaminated by microorganisms of several sources, including the farm environment, post-harvest handling and processing (Abadias et al., 2008). The microflora associated with raw fruits mostly includes yeasts and moulds (Burnett and Beuchat, 2000;Tournas, 2005). ...
Mango has a short shelf-life after harvesting. The use of edible coatings on the elaboration of minimally
processed mango is an alternative for its commercialization. In the present work edible coatings based
on chitosan, starch-salicylic acid and starch-cinnamaldehyde-thymol were applied to fresh cut-mango.
Weight loss, soluble solids, titratable acidity, color and microbiological analyses were studied along
storage for 12 days at 8 °C and 90% relative humidity. Titratable acidity was the highest for mangoes
coated with chitosan and the lowest was for starch-salicylic acid coating. Regarding instrumental
texture, fruit coated with chitosan showed a higher penetration force compared to fruit coated with
starch and uncoated samples. Microbiological results showed that all coated mangoes inhibited
growing of fungi and yeast whereas uncoated samples showed an increase of both microorganisms
along 12 days of storage period.
... NEW has the potential to reduce foodborne pathogens on vegetable surfaces (Abadias et al., 2008). However, information regarding its effects on bioactive compounds in medicinal plants is lacking. ...
Concerns have been raised about viral contamination, including in crops due to the recent coronavirus disease 2019 pandemic. Limited evidence is available to support the use of sanitizing agents for human coronavirus-contaminated medicinal plants. Thus, we aimed to investigate the persistence of infectious human coronavirus OC43 (HCoV-OC43) as a SARS-CoV-2 surrogate in storage conditions and the capability of neutral electrolyzed water (NEW) to inactivate coronavirus, including in fresh plants such as C. asiatica. The levels of infectious HCoV-OC43 and the triterpenoid content of C. asiatica were quantified using a plaque assay and high-performance liquid chromatography, respectively. The results showed that the persistence of HCoV-OC43 on C. asiatica leaves is identical to that on inert polystyrene. When covered and kept at room temperature with high humidity (>90% RH), HCoV-OC43 can be stable on C. asiatica leaves for at least 24 h. NEW with 197 ppm of available chlorine concentration (ACC) was effective in inactivating both infectious HCoV-OC43 and SARS-CoV-2 in suspension (≥3.68 and ≥4.34 log reduction, respectively), and inactivated dried HCoV-OC43 on the surfaces of C. asiatica leaves (≥2.31 log reduction). Soaking C. asiatica leaves for 5 min in NEW with 205 ppm of ACC or water resulted in significantly higher asiaticoside levels (37.82 ± 0.29 and 35.32 ± 0.74 mg/g dry weight, respectively), compared to the unsoaked group (29.96 ± 0.78 mg/g dry weight). These findings suggest that although coronavirus-contaminated C. asiatica leaves can pose a risk of transmission, NEW could be an option for inactivation.
... electrical conductivity-1160 mV, available Cl-50 mg/L) for 15 s could limit the proliferation of Listeria monocytogenes, Salmonella typhimurium, and E. coli. The population capacity was 1.23, 1.67, and 1.81 log on the stainless-steel surface, and it was deduced that a longer contact time could increase the disinfection effect [66,90]. It was reported that in order to sterilize bovine hides before slaughter, electrically oxidized water constituting 70.0 mg/L of available Cl was sprayed sequentially at a temperature of 60 • C. Sprays can reduce the amount of anaerobic bacteria by 3.5 logs CFU/100 cm 2 and the number of Enterobacter by 4.3 log CFU/100 cm 2 . ...
Electrolyzed water is a novel disinfectant and cleaner that has been widely utilized in the food sector for several years to ensure that surfaces are sterilized, and that food is safe. It is produced by the electrolysis of a dilute salt solution, and the reaction products include sodium hydroxide (NaOH) and hypochlorous acid. In comparison to conventional cleaning agents, electrolyzed water is economical and eco-friendly, easy to use, and strongly effective. Electrolyzed water is also used in its acidic form, but it is non-corrosive to the human epithelium and other organic matter. The electrolyzed water can be utilized in a diverse range of foods; thus, it is an appropriate choice for synergistic microbial control in the food industry to ensure food safety and quality without damaging the organoleptic parameters of the food. The present review article highlights the latest information on the factors responsible for food spoilage and the antimicrobial potential of electrolyzed water in fresh or processed plant and animal products.
... The oxidation-reduction potential (ORP) High (more than 1000) contains free chlorine ions, on the other electrode the cathode produces Catholyte It has a pH of 10.0-11.5 and dissolved hydrogen with redox potential (ORP) Very low (-800 to -900mV). The biggest advantage of using electrolyzed water is to stop the activity of pathogens and it has less impact on the environment and users due to the absence of chemicals [6] and the use of neutralized electrolytic water (ANK) in the water given to poultry, it is considered a new method of treatment because of its beneficial effect on the health status [7; 8]. ...
This experiment was conducted to study the effect of ionized water on qualitative characteristics of the egg of layer hen from the period 25/October/2020 to 13/March/2021 (20 weeks). 105 hens (Lohmann-classic) strains were randomly divided into 5 groups (21 hen / group). Each group was subdivided into 3 replicates ( 7 hen / replicates). Hens in the control group provide tap water with pH (7.14), while hens in the 2nd and 3rd groups provide alkaline ionized water with pH (8.5, 9.5) respectively, 4th and 5th groups provide acidic ionized water with pH (5, 4) respectively. Results showed yolk weight rate significantly increase in the alkaline ionized water group (T2) as compared with the control and no significant differences were observed between groups on other egg quality traits. In addition, ionized water good method to improve water quality and some qualitative characteristics of eggs.
... They allow the consumer to procure only the quantities of fresh produce required. While fresh-cut produce requires relatively little product transformation, it requires investment in technology, equipment, management systems and strict observance of food safety principles and practices to ensure product quality 17,18,19 . ...
Raw salad vegetables are evaluated for the consumer’s perceptions on taking ready to eat fresh cut-vegetables and the effectiveness of some non-chlorine disinfectants [peracetic acid (PAA), shell powder (SP) and hydrogen peroxide (H2O2)] in improving the microbial safety, quality and shelf life of ready to eat fresh-cut vegetables (lettuce, carrot and cucumber) at ambient and refrigeration temperature. Consumer’s perception study results identified three clusters of consumers, whose preferences are related to purchasing styles and socio-demographic variables.The overall positive attitude of consumers was evident towards convenience, taste and appearance, but safety and health benefit attributes get importance while buying the ready to eat fresh-cut vegetables.The microbiological and visual observation result demonstrated that, all the non-chlorine sanitizers used were able to decrease the bacterial population in fresh-cut vegetables initially; however, microbial population increases or remain constant or decrease depending on the types of vegetables, storage temperature and duration. In addition, among the wash-sanitizers, PAA and H2O2 showed better microbial reduction for fresh-cut lettuce, and cucumber, and SP showed better microbial reduction for fresh-cut carrot. Irrespective of sanitizer treatment refrigerated storage showed better visual quality, microbial safety and shelf life of fresh-cut produce. Therefore, this study results suggested that washing fresh-cut vegetables with produce specific sanitizer and stored at refrigerated temperature keep the quality of fresh-cut produce better compared to ambient storage. Bangladesh J Microbiol, Volume 38, Number 2, December 2021, pp 51-62
... However, Stopforth et al. studied AEW (ACC 50 ppm) in leafy greens and revealed no significant difference in the antibacterial effect above 1 min. Some other authors studied the effectiveness of EW for longer exposure times and reported similar or even lower bacterial reductions [55,56]. The reason may be that the dissociation of free chlorine or interference such as organic matter over a relatively short time [57]. ...
Electrolyzed water (EW) has been proposed as a novel promising sanitizer and cleaner in recent years. It is an effective antimicrobial and antibiofilm agent that has several advantages of being on the spot, environmentally friendly, cheap, and safe for human beings. Therefore, EW has been applied widely in various fields, including agriculture, food sanitation, livestock management, medical disinfection, clinical, and other fields using antibacterial technology. Currently, EW has potential significance for high-risk settings in hospitals and other clinical facilities. The research focus has been shifted toward the application of slightly acidic EW as more effective with some supplemental chemical and physical treatment methods such as ultraviolet radiations and ultrasound. This review article summarizes the possible mechanism of action and highlights the latest research studies in antimicrobial applications.
... The various types of EOW described in literature include acidic EOW (pH 2-3.5), slightly acidic EOW (pH 5-6.5), alkaline EOW (pH 10-13), slightly alkaline EOW (pH 8-10), and neutral EOW (pH 7-8) (Rahman et al., 2016). Neutral EOW is used as a disinfectant in soaking and washing fresh vegetables (Abadias et al., 2008) or fruit (Torlak, 2014) and in the seafood (Khazandi et al., 2017) and meat industries (Han et al., 2018;Veasey and Muriana, 2016). It can also be used to mist greenhouses, sterilise equipment and soil, and as an additive to irrigation water. ...
The aim of the study was to analyse the effects of pH-neutral electrolysed oxidising water (pH-neutral EOW), prepared by using the Envirolyte® system, on the growth and development of chrysanthemums. The experiment included two varieties of potted ('Tonka Blanc', 'Jahou CoCo') and two cut flower varieties of chrysanthemums ('Annecy White', 'Ninja'). The test plants planted in pots were irrigated with three different solutions of pH-neutral EOW (0%, 0.1% and 0.2%). Based on the results of the study, we can confirm that pH-neutral EOW has a significant effect on the growth and development of the studied chrysanthemum varieties. In potted chrysanthemums, we found a significant effect on the increased number and diameter of inflorescences, as well as fresh and dried weight of the plant and inflorescences. Chrysanthemums for cut flowers were taller and more developed, with a greater weight of the aboveground part of the plant. Its effect on the growth and development of the studied varieties depended on the solution of the mixture. Best results were observed with the 0.2% solution of pH-neutral EOW.
... Hypochlorous acid is the most active of the chlorine compounds and has high bactericidal activity (36). In several studies, the efficacy of NEW has been evaluated for reduction of bacterial population in fresh meat (12,35,42,43), eggshells (44), seafoods (28), and vegetables (1). If NEW were to be combined with other chemical disinfectants such as organic acids, its antimicrobial efficacy might increase. ...
This study was conducted to evaluate the antimicrobial efficacy of near-neutral electrolyzed water (NEW) and peroxyacetic acid (PAA) alone and in combination for reducing the foodborne pathogens Salmonella Typhimurium, Escherichia coli, and Listeria monocytogenes in pure culture and fresh chicken meat. The NEW treatments resulted in 100% inactivation of these organisms in pure culture at concentrations of 50, 100, and 200 μg/mL and 2 min of contact time at room temperature. The PAA treatments at concentrations of 100 and 200 μg/mL resulted in 100% inactivation of the tested pathogens. The combination of NEW and PAA had a greater bactericidal effect than did each individual treatment. The inoculated chicken meat samples were dipped for 10 min in each treatment solutions (100 and 200 μg/mL NEW, 200 and 400 μg/mL PAA, 100 μg/mL NEW + 200 μg/mL PAA) at room temperature. Samples dipped in water were used as a control. The greatest reduction was achieved with the combined treatment, which significantly (P < 0.05) reduced total cells and healthy cells of Salmonella Typhimurium, E. coli, and L. monocytogenes by 2.79 and 3.01, 2.63 and 2.75, and 1.47 and 1.99 log CFU/g, respectively. The findings of this study indicate that a combined treatment with NEW and PAA has potential as a novel antimicrobial agent to improve the microbial safety of fresh chicken meat. © 2021, International Association for Food Protection. All rights reserved.
... Thus, only half the volume of the sodium chloride solution (the stock solution) is obtained as a sterilizing solution. An aqueous solution (neutral electrolyzed water, or NEW) obtained by mixing the aforementioned acidic electrolyzed water in the anode chamber and alkaline water in the cathode chamber also has potent sterilizing action [15][16][17]. However, this is a mixture of 2 solutions, so it is unlikely to stabilize as the chemical reaction proceeds. ...
Slightly acidic electrolyzed water (SAEW) was developed by Japanese companies over 20 years ago. SAEW has the advantage of potent sterilizing action while being relatively safe. This study evaluated the potential application of SAEW in spatial disinfection. Prior to experiments involving spatial spraying, the ability of SAEW to remove seven type of microorganisms that cause food poisoning was studied in vitro. Results indicated that free chlorine in SAEW, even at a low concentration (30 mg/L), was able to remove Cladosporium cladosporioides, a typical airborne fungus that degrades food, and spores such as Bacillus subtilis, a hardy bacterium. In an experiment involving spatial spraying, 3.43 log10 CFU/100 L of Staphylococcus epidermidis was sprayed in a room-sized space; the same space was then sprayed with SAEW. The number of settling microbes was measured and the sterilizing ability of SAEW was assessed. Results indicated that the concentration of S. epidermidis in the space was completely removed after 20 minutes of SAEW spraying. The above findings indicate that SAEW may be used to remove airborne microorganisms via spatial spraying.
... In case of the bacteria, the cell membranes of Escherichia coli and Staphylococcus aureus could be damaged when treated by electrolyzed water, but it could not make their DNA and RNA degraded. According to findings developed by Abadias et al. (2008), the bactericidal activity of NEW (containing approximately 50 ppm of free chlorine, pH 8.60) against E. coli O157:H7, Salmonella, L. innocua and E. carotovora on lettuce was similar to that of chlorinated water (120 ppm of free chlorine) with reductions of 1-2 log units. Seo et al. (2018), evaluating the decontamination of Brassica oleracea var. ...
The consumption of fresh-cut fruit is attributed to the health and convenience benefits of consumers. However, reports about associated-microorganism diseases have aroused the consumer's interest. Chlorine-based compounds are the classic method for the microbiological control. These compounds have been used to sanitize fruits and vegetables in the minimal processing industry worldwide, but they react with the organic matter present in the water that leads to the formation of potentially cancerous chlorinated compounds. Aiming to develop alternative technology to sodium hypochlorite, this study evaluated treatment with neutral electrolyzed water (NEW) on microbiology, quality and sensory parameters of fresh-cut mangoes. ‘Tommy Atkins’ mangoes were processed into cubes and treated by immersion in NEW solutions (0, 75, 150, 225 and 300 mg L⁻¹) or chlorine-based product at 200 mg L⁻¹, and then, stored at 3 ± 2 °C, 85 ± 5% RH for 0, 6 or 12 days. The microbiota of fresh-cut mangoes was reduced by NEW treatments similarly as observed by sanitization with commercial product. Nutritional components as vitamin C, carotenoids and phenolics were preserved by NEW treatments or commercial chlorine. Concerning the sensory aspects, the NEW at150 mg L⁻¹ presented the same good acceptability as observed for commercial chlorine and even lower off-flavor intensity than this chlorine-based sanitizer. Fresh-cut mangoes treated with NEW at different concentrations showed equivalent microbiological and quality parameters to the mango treated with commercial sanitizer, which allow to provide that electrolyzed water is a viable alternative to chlorine-based compounds as a disinfectant, considering the lower adverse impact on the environment and possibly on human health.
... For example, Junker et al. (2021) identified two wheat ATIs as strong activators of innate immune responses in monocytes, macrophages, and dendritic cells. While not specific to FD, this finding suggests that ATIs may fuel inflammation and immune reactions in intestinal immune disorders [63]. ...
Functional dyspepsia (FD) is a common disorder of gut-brain interaction, characterised by upper gastrointestinal symptom profiles that differentiate FD from the irritable bowel syndrome (IBS), although the two conditions often co-exist. Despite food and eating being implicated in FD symptom induction, evidence-based guidance for dietetic management of FD is limited. The aim of this narrative review is to collate the possible mechanisms for eating-induced and food-related symptoms of FD for stratification of dietetic management. Specific carbohydrates, proteins and fats, or foods high in these macronutrients have all been reported as influencing FD symptom induction, with removal of ‘trigger’ foods or nutrients shown to alleviate symptoms. Food additives and natural food chemicals have also been implicated, but there is a lack of convincing evidence. Emerging evidence suggests the gastrointestinal microbiota is the primary interface between food and symptom induction in FD, and is therefore a research direction that warrants substantial attention. Objective markers of FD, along with more sensitive and specific dietary assessment tools will contribute to progressing towards evidence-based dietetic management of FD.
... Among all these types, acidic EOW has got the most attention due to its highly efficient antimicrobial activity principle. Alkali EOW and [18] Neutral electrolyzed water Neutral electrolyzed water NEW 7-8 750 50 [14], [88], [67,40] NEW are also being researched for their efficacy in different antimicrobial applications, and other uses such as cleaning. Both acidic and alkali EOW are generated in an electrolysis chamber where the anode and cathode are separated with the help of a diaphragm. ...
Electrolyzed oxidizing water (EOW) is one of the promising novel antimicrobial agents that have recently been proposed as the alternative to conventional decontamination methods such as heat and chemical sanitizers. Acidic EOW with pH ranging from 2 to 5 is regarded most applicable in the antimicrobial treatment of vegetables and meats. Neutral and alkaline electrolyzed water have also been explored in few studies for their applications in the food industry. Neutral electrolyzed water is proposed to solve the problems related to the storage and corrosion effect of acidic EOW. Recently, the research focus has been shifted toward the application of slightly acidic EOW as more effective with some supplemental physical and chemical treatment methods such as ultrasound and UV radiations. The different applications of electrolyzed water range from drinking water and wastewater to food, utensil, and hard surfaces. The recent studies also conclude that electrolyzed water is more effective in suspensions as compared with the food surfaces where longer retention times are required. The commercialization of EOW instruments is not adopted frequently in many countries due to the potential corrosion problems associated with acidic electrolyzed water. This review article summarizes the EOW types and possible mechanism of action as well as highlights the most recent research studies in the field of antimicrobial applications and cleaning. Electrolyzed water can replace conventional chemical decontamination methods in the industry and household. However, more research is needed to know its actual mechanism of antimicrobial action along with the primary concerns related to EOW in the processing of different food products.
... Fresh and minimally processed fresh-cut products are naturally contaminated by microorganisms of several sources, including the farm environment, post-harvest handling and processing (Abadias et al., 2008). The microflora associated with raw fruits mostly includes yeasts and moulds (Burnett and Beuchat, 2000;Tournas, 2005). ...
Mango has a short shelf-life after harvesting. The use of edible coatings on the elaboration of minimally processed mango is an alternative for its commercialization. In the present work edible coatings based on chitosan, starch-salicylic acid and starch-cinnamaldehyde-thymol were applied to fresh cut-mango. Weight loss, soluble solids, titratable acidity, color and microbiological analyses were studied along storage for 12 days at 8 °C and 90% relative humidity. Titratable acidity was the highest for mangoes coated with chitosan and the lowest was for starch-salicylic acid coating. Regarding instrumental texture, fruit coated with chitosan showed a higher penetration force compared to fruit coated with starch and uncoated samples. Microbiological results showed that all coated mangoes inhibited growing of fungi and yeast whereas uncoated samples showed an increase of both microorganisms along 12 days of storage period.
... Due to its different mechanisms of action, EOW has a wide range of activity. Electrolyzed water has been evaluated for several food safety industrial applications, including use as a fresh produce wash [97,98], cleaning and decontamination of dairy facilities [99], plant production [100], pig and poultry production and food facilities [101]. Cold fogging with electrolyzed water has been effective in decontamination of rooms mainly in health care environments [102]. ...
Water treatment technologies have received great attention recently, as water is the most important nutritional element, and animals consume it daily in larger quantities than those of food. The ideal water treatment affects the chemical composition and physical properties of water, having a significant positive impact on the animal’s physiology, productivity, and welfare. Studies conducted on water ionization devices for broiler chickens remain limited; therefore, this study was planned to investigate the effect of ionized drinking water on the productive performance, physiological status, and carcass characteristics of broiler chicks. A total of 900 one-day-old broiler chicks were randomly and equally assigned to three groups, each with six replicates (50 birds/replicate). The first group (C) received tap drinking water and served as a control, while the second group (T1) received ionized drinking water from an ionizing device that worked for 1 h/100 L. The third group (T2) received ionized drinking water from an ionizing device that worked for 2 h/100 L. Water analysis for each treatment was performed. Productive traits, such as weekly body weight, feed intake, and water intake, were recorded. Hematological parameters and biochemical constituents were measured according to the reference’s description. Furthermore, carcass characteristics, such as carcass weight and dressing percentage, and bacterial count of the intestine, such as Lactobacilli and Coliform counts, were determined. From the results, ionized water (T1 and T2) had a negative ORP, which is often desirable as it suggests the presence of antioxidant properties and lower total dissolved solids (TDSs), heterotrophic plate count (HPC), and algal total count (ATC) than in tap water. The treated chicks showed higher final body weights and better feed conversion rates than the control. Ionized water also improved carcass quality characteristics, such as carcass weight and dressing percentage. T1 and T2 chicks exhibited higher hemoglobin, total protein, globulin, G and M immunoglobulin, and total antioxidant capacity (TAC) levels, as well as lower malondialdehyde (MDA) and low-density lipoprotein (LDL) levels than the control. Furthermore, they had lower pathogenic bacteria counts. Therefore, it is recommended to employ the ionizing approach for broiler chicken drinking water, particularly a 2 h/100 L ionization application, for better animal productivity, health, and welfare.
Although disinfection byproducts (DBPs) are well-known to be formed during the disinfection of drinking water and wastewater, a growing number of studies have also demonstrated that these unwanted contaminants are of great concern during agricultural produce processing, industrial processes, and household cooking. This chapter begins by examining the formation of DBPs during agricultural produce processing and industrial processes, outlining the disparities between food industry and drinking water disinfection. It discusses various sample pretreatment techniques and analytical methods used for detecting DBPs, as well as their occurrence and formation, classifying them into inorganic DBPs, organic low molecular weight DBPs, and organic high molecular weight DBPs. Minimizing the formation of DBPs during food processing in the industry can be achieved via optimization of disinfection conditions and production processes. The chapter then shifts focus to DBP formation during household cooking, exploring the impacts of cooking methods and food types on DBP formation. Overviews of detection and identification, formation and occurrence, and toxicity profiles are provided. Finally, the chapter ends with a look at strategies for controlling DBP formation to mitigate their presence in cooking processes, which is beneficial for ensuring food safety and public health.
Considering the high perishable nature of muscle foods (fish, poultry and red meat) and wide diversity in spoilage microorganisms responsible for spoilage, the prevalence of pathogenic microorganisms in muscle food spoilage is significant. There has been extensive coverage on the emergence of antibiotic resistance in food spoilage microbes in recent years. Chemical preservatives have been extensively employed for the preservation of muscle foods although they have been found to cause toxicity and are not environmentally sustainable. Nevertheless, the scientific community has shown a growing interest in recent breakthroughs in the utilization of innovative clean-label technologies for the preservation of muscle meals, owing to their sustainable characteristics. Among them pulsed light, electrolysed water and ozonation have been under wide exploration. The evaluated sustainable technologies have been found to effectively inhibit the microbial spoilage and reduce the development of antimicrobial resistance. This review discusses potentiality of sustainable technologies in preserving muscle foods with minimal deteriorative impact.
Over the last three decades, decontamination management of fresh fruits and vegetables (FFVs) in the packhouses and along the supply chains has been heavily dependent on chemical‐based wash. This has resulted in the emergence of resistant foodborne pathogens and often the deposition of disinfectant byproducts on FFVs, rendering them unacceptable to consumers. The management of foodborne pathogens, microbial contaminants, and quality of FFVs are a major concern for the horticultural industries and public health. Activated water systems (AWS), such as electrolyzed water, plasma‐activated water, and micro–nano bubbles, have gained significant attention from researchers over the last decade due to their nonthermal and nontoxic mode of action for microbial inactivation and preservation of FFVs quality. The aim of this review is to provide a comprehensive summary of recent progress on the application of AWS and their effects on quality attributes and microbial safety of FFVs. An overview of the different types of AWS and their properties is provided. Furthermore, the review highlights the chemistry behind generation of reactive species and the impact of AWS on the quality attributes of FFVs and on the inactivation/reduction of spoilage and pathogenic microbes (in vivo or in vitro). The mechanisms of action of microorganism inactivation are discussed. Finally, this work highlights challenges and limitations for commercialization and safety and regulation issues of AWS. The synergistic prospect on combining AWS for maximum microorganism inactivation effectiveness is also considered. AWS offers a potential alternative as nonchemical interventions to maintain quality attributes, inactivate spoilage and pathogenic microorganisms, and extend the shelf‐life for FFVs.
The food industry has extensively explored postharvest microbial control, seeking viable technologies to ensure food safety. Although numerous chlorine-based commercial sanitizers serve this purpose, many are plagued by constraints such as instability and diminished disinfectant efficacy. These issues arise from exposure to organic matter in wash water, light, or air. As an innovative and promising alternative, slightly acidic electrolyzed water (SAEW) has emerged, captivating attention for its robust sterilization potential and eco-friendliness in agricultural and food sectors. SAEW generated via electrolysis of a diluted hydrochloric acid (HCl) solution with concentrations ranging from 2 to 6% or aqueous solution of sodium chloride (NaCl) in a nonmembrane electrolytic chamber is reported to possess equivalent antimicrobial properties as strong acidic electrolyzed water (StAEW). In contrast to traditional chlorine sanitizers, SAEW leaves less chlorine residue on sanitized foods such fresh-cut fruit and vegetables, meat, poultry, and aquatic products due to its low available chlorine concentration (ACC). Its near neutral pH of 5 to 6.5 not only renders it environmentally benign but also mitigates the production of chlorine gas, a contrast to low pH conditions seen in StAEW generation. The bactericidal effect of SAEW against various strains of foodborne pathogens is widely believed and accepted to be due to the combined action of high oxidation-reduction-potential (ORP) reactions and undissociated hypochlorite/hypochlorous acid (HOCl). Consequently, a burgeoning interest surrounds the potential of SAEW for sanitation in the food industry, offering an alternative to address shortcomings in sodium hypochlorite solutions and even StAEW. It has been hypothesized from a number of studies that SAEW treatment can increase the quality and nutritional value of harvested fruits, which in turn may enhance their ability to be stored. Therefore, SAEW is not only a promising sanitizer in the food industry but also has the potential to be an efficient strategy for encouraging the accumulation of bioactive chemicals in plants, especially if it is used extensively. This review encapsulates the latest insights concerning SAEW, encompassing its antimicrobial effectiveness, sanitization mechanism, advantages vis-à-vis other sanitizers, and plausible applications across the food industry.
The trends toward healthy living, vegetarianism, and busy schedules have increased salad popularity. Salads are usually consumed raw without any thermal treatment, and therefore, without proper care they can become major vehicles for foodborne illness outbreaks. This review examines the microbial quality of 'dressed' salads which contain two or more vegetables/fruits and salad dressings. The possible sources of ingredient contamination, recorded illnesses/outbreaks, and overall microbial quality observed worldwide, besides the antimicrobial treatments available are discussed in detail. Noroviruses were most frequently implicated in outbreaks. Salad dressings usually play a positive role in influencing microbial quality. However, this depends on several factors like the type of contaminating microorganism, storage temperature, dressing pH and ingredients, plus the type of salad vegetable. Very limited literature exists on antimicrobial treatments that can be used successfully with salad dressings and 'dressed' salads. The challenge with antimicrobial treatments is to find ones sufficiently broad in spectrum, compatible with produce flavour which can be applied at competitive cost. It is evident that renewed emphasis on prevention of produce contamination at the producer, processor, wholesale and retail levels plus enhanced hygiene vigilance at foodservice will have a major impact on reducing the risk of foodborne illnesses from salads.
During the processing of poultry, disinfectants are commonly added to cooling water tanks called “chillers” to reduce microorganism populations that can affect food quality. The present study, evaluated the effectiveness of neutral electrolyzed water in a pilot-project-sized chiller for the elimination of pathogenic microorganisms in gizzards and necks chicken. The microbiological analysis of the samples was processed and analyzed in three different food microbiological analysis laboratories. The results demonstrated a maximum microbial load reduction of 1.97686 log CFU/g for Escherichia coli and 1.76313 log CFU/g for Staphylococcus aureus in all samples processed with neutral electrolyzed water. Sodium hypochlorite, a disinfectant in common industrial use, did not achieve significant reductions in microbial loads below those of untreated necks and gizzards for either of the microorganisms in question. Based on these results, this study thus proposes the use electrolyzed water as an alternative disinfectant to sodium hypochlorite for use in chillers; being a sustainable solution that differs from conventional disinfectants in its lack of human or environmental side effects.
L. monocytogenes has been linked to fresh produce and detected in the retail environment. This study simulated the retail practices (crisping, misting, and storage) of unbagged whole heads of romaine lettuce to determine the growth of L. monocytogenes and natural psychrotrophic microflora. Three nalidixic acid-resistant strains of L. monocytogenes strains were inoculated to each head of lettuce (≈5 log 10 CFU/g). For crisping, 24 heads of romaine lettuce were immersed in tap water or electrolyzed water (EW; free chlorine: 55 ppm) for 5 min, followed by holding at 5 ○ C for 2 h. The water-crisped (WC), EW crisped (EWC), or non-crisped (NC) lettuces were placed in a commercial refrigerated cabinet for misting at 5 ○ C. After 24-h misting, heads of lettuce were placed in perforated drain boxes with cover at 5 ○ C or 15 ○ C. The tap water and EW crisping achieved 1.3 and 2.9 log 10 CFU/g reduction of L. monocytogenes, respectively. Approximately 1 log additional reduction of L. monocytogenes in the non-crisped lettuce was shown after misting ( p < 0.05), but no significant effect of misting on the population of L. monocytogenes was observed on WC or EWC lettuces ( p > 0.05). Regardless of the storage temperature or misting, L. monocytogenes populations remained significantly ( p < 0.05) lower on EWC lettuce than NC and WC lettuce. On days 4 and 7 of storage, the natural psychrotrophic bacteria on lettuce stored at 5°C was significantly lower than stored at 15°C, and its population was not affected by crisping and misting. These provide insight into the influence of retail lettuce handling practices on the risk of L. monocytogenes.
Outbreaks involving romaine and iceberg lettuce are frequently reported in the United States. Novel technologies are needed to inactivate pathogens without compromising product quality and shelf life. In this study, the effects of a process aid composed of silver dihydrogen citrate, glycerin, and lactic acid (SGL) on Escherichia coli and Listeria monocytogenes concentrations on lettuce immediately after washing and during cold storage were evaluated. Sensory and quality attributes of fresh-cut iceberg lettuce were also evaluated. Laboratory results indicated that application of SGL solution for 30 second as a first step in the washing process resulted in a 3.15 log reduction in E. coli O157:H7 immediately after washing. For E. coli O157:H7 a significant difference between SGL treatment and all other treatments was maintained until day 7. On day zero, SGL led to a 2.94 log reduction of L. monocytogenes. However, there was no significant difference between treatments with or without SGL regardless of storage time. Pilot-plant results showed that samples receiving SGL spray followed by chlorinated flume wash exhibited a greater reduction (1.48 log) in nonpathogenic E. coli populations at the end of shelf life than other treatments (p<0.05). Additional pilot plant tests were conducted to investigate the hypothesis that SGL residues could continue to impact microbial survival on the final washed lettuce. Results show that pathogens introduced subsequent to flume washing of lettuce pretreated with SGL solution were not affected by antimicrobial residues. The final quality and shelf life of flume washed lettuce were also unaffected by pretreatment with SGL. In conclusion, the results of this study demonstrate that this new technology has the potential to accelerate E. coli die-off on fresh-cut lettuce during cold storage and improve product safety, while not affecting quality throughout the shelf life of the finished products.
Food safety is a burning issue in the present world. Safe sanitizers are obligatory for maintaining quality of food and increasing the shelf life of fresh produce and other agricultural products. Food industries have been using electrolyzed water (EW) as a unique sanitizer for the past two decades which has excellent results to reduce the microbial count. Hurdle technology, e.g., combination of EW with ultrasonication, short-term heat treatment, organic acids, and salts, found to have more effective results in reducing microorganisms which overcame the little shortcomings with EW like corrosiveness and maintained organoleptic qualities. In this chapter, we are going to discuss the production of EW and its combination with ultrasonication, short-term heat treatment, organic acids, and salts to produce a novel sanitizer.
Fresh fruits and vegetables carry a heavy load of microorganisms which may cause the risks of food‐borne illness to the consumer. Even after washing with water, there is a need for sanitization and disinfection to drop down a load of harmful microbes under the safe limit. Sanitizers and disinfectants are not only cost‐effective but also non‐hazardous and eco‐friendly. Moreover, they should not hamper the organoleptic and nutritional properties of fresh produce. With rising demand for safe, nutritious, and fresh fruits and vegetables, many new disinfectants and treatments are commercially available. During this COVID‐19 outbreak, knowledge of sanitizers and disinfectants for fresh fruits and vegetables is very important. This review focuses on working principles, applications, and related legislation of physical and chemical disinfection technologies (chlorine, chlorine dioxide, ozone, organic acids, electrolyzed water, irradiation, ultrasound etc.) and their effectiveness for shelf‐life extension of fresh produce.
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.
Fresh fruits and vegetables are susceptible to attack by spoilage and pathogenic microorganisms if not handled correctly during or after harvest. Postharvest disinfection of commodities is a curative operation to inhibit fungal pathogens and human bacterial pathogens and therefore enhance food safety. Deterioration of fruits and vegetables can only be prevented by adopting the inhibition of postharvest pathogens and thus ensuring prolonged storage life. This chapter comprises factual, chemical, and administrative context on some of the essential sanitizers existing for the practice nowadays. These include chlorine, chlorine dioxide, ozone, ethanol, hydrogen peroxide, organic acids, and electrolyzed water. A broad description about postharvest application, disinfection mechanism, and regulatory guidelines of these sanitizers has been given in this chapter. This chapter concludes that disinfectant is a vital tool to reduce postharvest decay in fruits and vegetables. In some conditions, sanitization is a pretreatment to the productive employment of postharvest methodology. This chapter clears the controversial, unjustified, and bad reputation of the use of chemical disinfectants as they leave no or much lesser amounts of remnants of the nonhazardous level. The world may consider the use of chemical disinfectants in an eco-friendly way.
A study was undertaken to investigate the cause of the bacteriostatic activity of fresh-cut spinach leaves against Listeria monocytogenes. L. monocytogenes was cultivated in pure tryptic soy broth for use as a monoculture, in tryptic soy broth containing 10 mg ml−1 of autoclaved or nonautoclaved freeze-dried spinach powder, and in tryptic soy broth in mixed cultures with various microorganisms isolated from fresh-cut spinach, including Pseudomonas fluorescens biovar I, P. fluorescens biovar III, Staphylococcus xylosus, and an undefined culture of mesophilic aerobic microorganisms (MAMs) isolated from freeze-dried spinach powder. These microorganisms were inoculated at 4.4 log CFU ml−1 and L. monocytogenes was inoculated at 2.4 and 4.4 log CFU ml−1. After 24 h of incubation at 30°C, the populations of the two inoculum levels L. monocytogenes increased to 9.0 and 9.6 log CFU ml−1 in the tryptic soy broth control, to 5.4 and 7.5 in nonautoclaved spinach powder cultures, and to 8.8 and 9.1 log CFU ml−1 in autoclaved spinach powder cultures; In mixed cultures with biovar I of P. fluorescens, L. monocytogenes increased to 7.4 and 8.6 log CFU ml−1; with biovar III to 7.7 and 9.1, with S. xylosus to 7.8 and 9.2, and with the MAMs to 7.1 and 8.0 CFU ml−1 in the low and high listerial inoculum cultures respectively. The LSD(0.05) of the means were 0.5 and 0.6, respectively. The freeze-dried spinach powder had an inhibitory effect on the growth of L. monocytogenes. The inhibitory effect was greatly decreased when the native microorganisms were almost eliminated by heating or irradiation. These results indicate that if L. monocytogenes is present as a contaminant on fresh-cut spinach, its growth probably will be restricted by native microorganisms.
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 efficacy of electrolyzed oxidizing (EO) and acidified chlorinated water (45 ppm residual chlorine) was evaluated in killing Escherichia coli O157:H7 and Listeria monocytogenes on lettuce. After surface inoculation, each leaf was immersed in 1.5 L of EO or acidified chlorinated water for 1 or 3 min at 22 °C. Compared to a water wash only, the EO water washes significantly decreased mean populations of E. coli O157:H7 and L. monocytogenes by 2.41 and 2.65 log10 CFU per lettuce leaf for 3 min treatments, respectively (p < 0.05). However, the difference between the bactericidal activity of EO and acidified chlorinated waters was not significant (p > 0.05). Change in the quality of lettuce subjected to the different wash treatments was not significant at the end of 2 wk of storage.
The ability of peracetic acid and peroctanoic acid sanitizers to inactivate mixed-culture biofilms of a Pseudomonas sp. and Listeria monocytogenes on stainless steel was investigated. Types of biofilms tested included a 4-h attachment of the mixed-cell suspension and a 48-h biofilm of mixed culture formed in skim milk or tryptic soy broth. Biofilm-containing coupons were immersed in solutions of hypochlorite, peracetic acid, and peroctanoic acid either with or without organic challenge. Organic challenge consisted of either coating the biofilms with milk that were then allowed to dry, or adding milk to the sanitizing solution to achieve a 5% concentration. Surviving cells were enumerated by pouring differential agar directly on the treated surfaces. The peracid sanitizers were more effective than chlorine for inactivating biofilm in the presence of organic challenge. The 48-h mixed-culture biofilm grown in milk was reduced to less than 3 CFU/cm2 by 160 ppm of peracid sanitizer after 1 min of exposure. Peroctanoic acid was more effective than peracetic acid against biofilm cells under conditions of organic challenge. Pseudomonas and L. monocytogenes were inactivated to similar levels by the sanitizer treatments, even though Pseudomonas predominated in the initial biofilm population.
One milliliter of culture containing a five-strain mixture of Escherichia coli O157:H7 (approximately 10(10) CFU) was inoculated on a 100-cm2 area marked on unscarred cutting boards. Following inoculation, the boards were air-dried under a laminar flow hood for 1 h, immersed in 2 liters of electrolyzed oxidizing water or sterile deionized water at 23 degrees C or 35 degrees C for 10 or 20 min; 45 degrees C for 5 or 10 min; or 55 degrees C for 5 min. After each temperature-time combination, the surviving population of the pathogen on cutting boards and in soaking water was determined. Soaking of inoculated cutting boards in electrolyzed oxidizing water reduced E. coli O157:H7 populations by > or = 5.0 log CFU/100 cm2 on cutting boards. However, immersion of cutting boards in deionized water decreased the pathogen count only by 1.0 to 1.5 log CFU/100 cm2. Treatment of cutting boards inoculated with Listeria monocytogenes in electrolyzed oxidizing water at selected temperature-time combinations (23 degrees C for 20 min, 35 degrees C for 10 min, and 45 degrees C for 10 min) substantially reduced the populations of L. monocytogenes in comparison to the counts recovered from the boards immersed in deionized water. E. coli O157:H7 and L. monocytogenes were not detected in electrolyzed oxidizing water after soaking treatment, whereas the pathogens survived in the deionized water used for soaking the cutting boards. This study revealed that immersion of kitchen cutting boards in electrolyzed oxidizing water could be used as an effective method for inactivating foodborne pathogens on smooth, plastic cutting boards.
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.
To identify the primary component responsible in electrolyzed oxidizing (EO) water for inactivation, this study determined the concentrations of hypochlorous acid (HOCl) and hypochlorite ions (OCl-) and related those concentrations to the microbicidal activity of the water. The ultraviolet absorption spectra were used to determine the concentrations of HOCl and OCl- in EO water and the chemical equilibrium of these species with change in pH and amperage. EO water generated at higher amperage contained a higher chlorine concentration. The maximum concentration of HOCl was observed around pH 4 where the maximum log reduction (2.3 log10 CFU/ml) of Bacillus cereus F4431/73 vegetative cells also occurred. The high correlation (r = 0.95) between HOCl concentrations and bactericidal effectiveness of EO water supports HOCl's role as the primary inactivation agent. Caution should be taken with standard titrimetric methods for measurement of chlorine as they cannot differentiate the levels of HOCl present in EO water of varying pHs.
Salmonella enterica serotype Baildon, a rare serotype, was recovered from 86 persons in eight states; 87% of illnesses began during a 3-week period ending January 9, 1999. Raw restaurant-prepared tomatoes were implicated in multiple case-control studies. Contamination likely occurred on the farm or during packing; more effective disinfection and prevention strategies are needed.
Effects of storage temperature (1, 5, and 10 degrees C) on growth of microbial populations (total aerobic bacteria, coliform bacteria, Bacillus cereus, and psychrotrophic bacteria) on acidic electrolyzed water (AcEW)-treated fresh-cut lettuce and cabbage were determined. A modified Gompertz function was used to describe the kinetics of microbial growth. Growth data were analyzed using regression analysis to generate "best-fit" modified Gompertz equations, which were subsequently used to calculate lag time, exponential growth rate, and generation time. The data indicated that the growth kinetics of each bacterium were dependent on storage temperature, except at 1 degrees C storage. At 1 degrees C storage, no increases were observed in bacterial populations. Treatment of vegetables with AcEW produced a decrease in initial microbial populations. However, subsequent growth rates were higher than on nontreated vegetables. The recovery time required by the reduced microbial population to reach the initial (treated with tap water [TW]) population was also determined in this study, with the recovery time of the microbial population at 10 degrees C being <3 days. The benefits of reducing the initial microbial populations on fresh-cut vegetables were greatly affected by storage temperature. Results from this study could be used to predict microbial quality of fresh-cut lettuce and cabbage throughout their distribution.
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.
A study was conducted to evaluate the efficacy of electrolyzed acidic water, 200-ppm chlorine water, and sterile distilled water in killing Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on the surfaces of spot-inoculated tomatoes. Inoculated tomatoes were sprayed with electrolyzed acidic water, 200-ppm chlorine water, and sterile distilled water (control) and rubbed by hand for 40 s. Populations of E. coli O157:H7, Salmonella, and L. monocytogenes in the rinse water and in the peptone wash solution were determined. Treatment with 200-ppm chlorine water and electrolyzed acidic water resulted in 4.87- and 7.85-log10 reductions, respectively, in Escherichia coli O157:H7 counts and 4.69- and 7.46-log10 reductions, respectively, in Salmonella counts. Treatment with 200-ppm chlorine water and electrolyzed acidic water reduced the number of L. monocytogenes by 4.76 and 7.54 log10 CFU per tomato, respectively. This study's findings suggest that electrolyzed acidic water could be useful in controlling pathogenic microorganisms on fresh produce.
An examination was made of the efficacy of acidic electrolyzed water (AcEW, 30 ppm free available chlorine), ozonated water (5 ppm ozone), and a sodium hypochlorite solution (NaOCl, 150 ppm free available chlorine) for use as potential sanitizers of cucumbers and strawberries. AcEW and NaOCl reduced the aerobic mesophiles naturally present on cucumbers within 10 min by 1.4 and 1.2 log CFU per cucumber, respectively. The reduction by ozonated water (0.7 log CFU per cucumber) was significantly less than that of AcEW or NaOCl (P < or = 0.05). Cucumbers washed in alkaline electrolyzed water for 5 min and then treated with AcEW for 5 min showed a reduction in aerobic mesophiles that was at least 2 log CFU per cucumber greater than that of other treatments (P < or = 0.05). This treatment was also effective in reducing levels of coliform bacteria and fungi associated with cucumbers. All treatments offered greater microbial reduction on the cucumber surface than in the cucumber homogenate. Aerobic mesophiles associated with strawberries were reduced by less than 1 log CFU per strawberry after each treatment. Coliform bacteria and fungi associated with strawberries were reduced by 1.0 to 1.5 log CFU per strawberry after each treatment. Microbial reduction was approximately 0.5 log CFU per strawberry greater on the strawberry surface than in the strawberry homogenate. However, neither treatment was able to completely inactivate or remove the microorganisms from the surface of the cucumber or strawberry.
The increasing availability of bagged prepared salad vegetables reflects consumer demand for fresh, healthy, convenient, and additive-free foods that are safe and nutritious. During May and June 2001 a study of retail bagged prepared ready-to-eat salad vegetables was undertaken to determine the microbiological quality of these vegetables. Examination of the salad vegetables revealed that the vast majority (3,826 of 3,852 samples; 99.3%) were of satisfactory or acceptable microbiological quality according to Public Health Laboratory Service microbiological guidelines, while 20 (0.5%) samples were of unsatisfactory microbiological quality. Unsatisfactory quality was due to Escherichia coli and Listeria spp. (not Listeria monocytogenes) levels in excess of 10(2) CFU/g. However, six (0.2%) samples were of unacceptable microbiological quality because of the presence of Salmonella (Salmonella Newport PT33 [one sample], Salmonella Umbilo [three samples], and Salmonella Durban [one sample]) or because of a L. monocytogenes level of 660 CFU/g, which indicates a health risk. In each case, the retailer involved and the UK Food Standards Agency were immediately informed, and full investigations were undertaken. Nineteen cases of Salmonella Newport PT33 infection were subsequently identified throughout England and Wales. The outbreak strain of Salmonella Newport PT33 isolated from the salad and from humans had a unique plasmid profile. Campylobacter spp. and E. coli O157 were not detected in any of the samples examined. The presence of Salmonella, as well as high levels of L. monocytogenes, is unacceptable. However, minimally processed cut and packaged salad is exposed to a range of conditions during growth, harvest, preparation, and distribution, and it is possible that these conditions may increase the potential for microbial contamination, highlighting the necessity for the implementation of good hygiene practices from farm to fork to prevent contamination and/or bacterial growth in these salad products.
This study evaluated the efficacy of neutral electrolyzed water (NEW; 64.1 mg/liter of active chlorine) to reduce populations of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Listeria monocytogenes on plastic and wooden kitchen cutting boards. Its effectiveness was compared with that of a sodium hypochlorite solution (NaClO; 62.3 mg/liter of active chlorine). Inoculated portions of cutting boards were rinsed in either NEW or NaClO solutions, or deionized water (control). Plastic boards were rinsed for 1 min and wooden boards for 1 and 5 min. After each treatment, the surviving population of each strain was determined on the surface and in the soaking water. No significant difference (P > or = 0.05) was found between the final populations of each strain with regard to the treatment solutions (NEW or NaClO). However, a significant difference (P < or = 0.05) was revealed between surface materials after 1 min of washing. Whereas in plastic boards the initial bacterial populations were reduced by 5 log CFU/50 cm2, in wooden cutting boards they underwent a reduction of <3 log CFU/50 cm2. A 5-min exposure time yielded reductions of about 4 log CFU/50 cm2. The surviving populations of all bacteria in NEW and NaCIO washing solutions were <1 log CFU/ml after soaking both surfaces. This study revealed that NEW treatment is an effective method for reducing microbial contamination on plastic and wooden cutting boards. NEW efficacy was comparable to that of NaCIO, with the advantage of having a larger storage time.
Since the beginning of 2007, the Health Protection Agency (HPA) Laboratory of Enteric Pathogens (LEP) has reported on 51 human isolates of Salmonella Senftenberg in England and Wales. This represents a significant rise compared to less than 10 in the same time period in 2006 and 2005. Of the 51 isolates, 35 (69%) have been received since 8 April (Week 15).
Fresh basil, sampled in May as part of a United Kingdom wide survey of fresh herbs on retail sale, was found to be contaminated with S. Senftenberg. The HPA launched microbiological and epidemiological investigations to elucidate the causes of this outbreak.
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.
Summary Demand for fresh, convenient, minimally processed vegetables has led to an increase in the quantity and variety of products available to the consumer. Modified atmosphere packaging, in combination with refrigeration, is increasingly being employed as a mild preservation technique to ensure quality and storage-life. The fresh nature of these products, together with the mild processing techniques and subsequent storage conditions, have presented indigenous and pathogenic microorganisms with new ecosystems and potential infection vehicles; a number of outbreaks of foodborne disease being attributed to their consumption. Psychrotrophic pathogens and pathogens which are capable of maintaining an infectious potential under mild preservation regimes are of particular concern; Listeria monocytogenes, Aeromonas hydrophila and Clostridium botulinum being amongst the most notable. This review describes the processing, packaging and storage procedures involved in the production of minimally processed vegetables, and details their impact upon the survival and growth of associated pathogens. Gaps in our current understanding of the consequences of this novel technology for microbiological safety are highlighted.
The effect of electrolyzed water on total microbial count was evaluated on several fresh-cut vegetables. When fresh-cut carrots, bell peppers, spinach, Japanese radish, and potatoes were treated with electrolyzed water (pH 6.8, 20 ppm available chlorine) by dipping, rinsing, or dipping/blowing, microbes on all cuts were reduced by 0.6 to 2.6 logs CFU/g. Rinsing or dipping/blowing were more effective than dipping. Electrolyzed water containing 50 ppm available chlorine had a stronger bactericidal effect than that containing 15 or 30 ppm chlorine for fresh-cut carrots, spinach, or cucumber. Electrolyzed water did not affect tissue pH, surface color, or general appearance of fresh-cut vegetables.
Fresh-cut lettuce samples inoculated with S. Typhimurium, E. coli O157:H7 or L. monocytogenes were dipped into 300 ppm electrolyzed water (EW) at pH 4 to 9 and 30 °C for 5 min. The effects of treatment pH on bacterial reduction and visual quality of the lettuce were determined. The treatments at pH 4 and 8 resulted in the most effective inactivation of E. coli O157:H7, but the effect of pH was not significant (P > 0.05) for S. Typhimurium and L. monocytogenes. The treatment at pH 7 retained the best visual quality of lettuce, and achieved a reduction of approximately 2 log CFU/g for above 3 bacteria.
ABSTRACTASTM A-36 medium carbon steel, 110 copper, 3003-H14 aluminum, polyvinylchloride (PVC) type 1 and 304 stainless steel coupons were immersed in electrolyzed (EO) water, chlorine water, modified EO water and deionized water for a period of 8 days, and the properties of these types of water, weights and surface roughness of the coupons were monitored. EO water significantly increased (P < 0.05) the surface roughness of carbon steel, aluminum and copper with time; however, chlorine water, modified EO water and deionized water produced minimal changes on these materials. Regardless of the treatment water used, the surface roughness of stainless steel and PVC essentially remained the same. Carbon steel, copper, aluminum and stainless steel had a fair, good, good and outstanding corrosion resistance in EO water, respectively. Chlorine and modified EO water had a much less corrosive effect than EO water on all the materials tested.
Modified-atmosphere packaging (MAP) and subsequent storage at refrigeration temperature has been developed over the last decade as an adequate technique to prolong high quality shelf-life of minimally processed vegetables. The MAP system employed should be carefully tailored to the physiological and microbiological characteristics of the product in order to achieve good quality, safe products. In the current investigation, controlled atmosphere conditions were employed that mimicked the packaging of fresh cut chicory endive under modified atmospheres in order to establish the microbiological characteristics. It was found that the modified-atmosphere conditions that were favourable for product quality, retarded growth of spoilage micro-organisms during storage at low temperature. Growth of the psychrotrophic pathogen Listeria monocytogenes, inoculated on the product, was not inhibited. The extent to which the pathogen grew depended on its initial number, type of chicory endive and size of the population of competitive spoilage microflora. Reducing the initial microbial load by disinfection could minimize microbial spoilage and improve the safety status of the product. However, L. monocytogenes grew better on disinfected produce than on non-disinfected or water-rinsed produce, indicating the practical importance of avoiding recontamination after disinfection.
In 1995, the National Advisory Committee on Microbiological Criteria for Foods (Committee) was asked to investigate and characterize the association between cases for foodborne illness and fresh produce. The Committee was asked to provide recommendations that could be employed to reduce the risk of foodborne outbreaks associated with these commodities. In furtherance of this assignment, the Committee reviewed current epidemiologic data, the microbial ecology of the outbreak-associated organisms, and considered the current industry practices used for growing, harvesting, packing and distribution. An evaluation of these data provided a basis for hazard identification and the development of related control measures.The Committee has developed seven specific recommendations: Good Agricultural Practices (GAP) and Good Manufacturing Practices (GMP) should be developed that will provide guidance on those agricultural and processing steps that can reduce pathogen levels on fresh produce. While Hazard Analysis Critical Control Point Programs (HACCP) would be likely to provide the greatest assurance of the safety of these products, there are presently insufficient data upon which to develop such progams. Proactive and practical education programs are needed at all steps in the process, i.e., from the field to the consumer's plate. Additional data are needed to conduct effective risk assessments of the microbial hazards associated with fresh produce. Better product identification and tracing systems are needed for outbreak investigations. Research must be conducted to fill some of the current knowledge gaps in order that improved intervention strategies can be employed. Steps should be taken to ‘streamline’ approval processes for new technologies that will reduce/eliminate microbial hazards.
These guidelines for the microbiological quality of ready-to-eat foods represent a revision and expansion of guidelines first published by the PHLS in September 1992 and revised in March 1996. The latest guidelines incorporate many of the constructive comments received from food examiners and other microbiologists within and outside the PHLS and from environmental health officers throughout the United Kingdom. This document reviews the changes and the reasons they were made and sets out the new guidelines. It also clarifies the role of food examiners in interpreting the microbiological results of formal samples.
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.
A total of 890 samples of fresh produce obtained from Norwegian markets were examined in order to assess the bacteriological quality of the products and their potential public health risk. The samples comprised lettuce, pre-cut salads, growing herbs, parsley and dill, mushrooms and strawberries. The samples were analysed for the presence of thermotolerant coliform bacteria (TCB), Escherichia coli O157, Salmonella spp., Listeria monocytogenes, Staphylococcus spp., and Yersinia enterocolitica. Neither Salmonella spp. nor E. coli O157 were isolated. For all product groups included, TCB were isolated from a small proportion of samples. Three samples harboured L. monocytogenes; one of the isolates belonging to serogroup 1 (champignons) and two of the isolates belonging to serogroup 4 (Chinese leaves and strawberries). Staphylococci were isolated from a relatively large proportion of the samples of strawberries and mushrooms. However, only four isolates were identified as S. aureus (non-toxinogenic). By the use of PCR, the presence of Y. enterocolitica was indicated in a few of the samples of lettuce, whilst no positive samples were found using a culturing method. The study shows that the occurrence of pathogenic bacteria and TCB in the products analysed was quite low. Nevertheless, the results indicate that the type of products analysed may contain pathogenic bacteria and thereby represent a risk to the consumers in regard to food-borne diseases.
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.
To determine the efficacy of neutral electrolyzed water (NEW) in killing Escherichia coli O157:H7, Salmonella enteritidis and Listeria monocytogenes, as well as nonpathogenic E. coli, on the surface of tomatoes, and to evaluate the effect of rinsing with NEW on the organoleptic characteristics of the tomatoes.
The bactericidal activity of NEW, containing 444 or 89 mg l(-1) of active chlorine, was evaluated over pure cultures (8.5 log CFU ml(-1)) of the above-mentioned strains. All of them were reduced by more than 6 log CFU ml(-1) within 5 min of exposure to NEW. Fresh tomatoes were surface-inoculated with the same strains, and rinsed in NEW (89 mg l(-1) of active chlorine) or in deionized sterile water (control), for 30 or 60 s. In the NEW treatments, independent of the strain and of the treatment time, an initial surface population of about 5 log CFU sq.cm(-1) was reduced to <1 log CFU sq.cm(-1), and no cells were detected in the washing solution by plating procedure. A sensory evaluation was conducted to ascertain possible alterations in organoleptic qualities, yielding no significant differences with regard to untreated tomatoes.
Rinsing in NEW reveals as an effective method to control the presence of E. coli O157:H7, S. enteritidis and L. monocytogenes on the surface of fresh tomatoes, without affecting their organoleptic characteristics. This indicates its potential application for the decontamination of fresh produce surfaces.
A survey of fresh and minimally-processed fruit and vegetables, and sprouts was conducted in several retail establishments in the Lleida area (Catalonia, Spain) during 2005–2006 to determine whether microbial contamination, and in particular potentially pathogenic bacteria, was present under these commodities. A total of 300 samples—including 21 ready-to-eat fruits, 28 whole fresh vegetables, 15 sprout samples and 237 ready-to-eat salads containing from one to six vegetables—were purchased from 4 supermarkets. They were tested for mesophilic and psychrotrophic aerobic counts, yeasts and moulds, lactic acid bacteria, Enterobacteriaceae, presumptive E. coli and Listeria monocytogenes counts as well as for the presence of Salmonella, E. coli O157:H7, Yersinia enterocolitica and thermotolerant Campylobacter.
Japan prepares as O157 strikes again Electrolyzed water as a disinfectant for fresh-cut vegetables
- E Gutierrez
Gutierrez, E., 1997. Japan prepares as O157 strikes again. Lancet 349, 1156. Izumi, H., 1999. Electrolyzed water as a disinfectant for fresh-cut vegetables. Journal of Food Science 64, 536–539.
Surface decontamination of fruits and vegetables eaten raw: a review
- L R Beuchat
Beuchat, L.R., 1998. Surface decontamination of fruits and vegetables eaten raw: a review. WHO/FSF/FOS/98.
World Health Organisa-tion
- Food Safety
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Food Safety Unit. World Health Organisa-tion. URL: http://www.who.int/foodsafety/publications/fs_management/en/ surface_decon.pdf.
International outbreak of Sal-monella Senftenberg in 2007 Guidelines for the micro-biological quality of some ready-to-eat foods sampled at the point of sale
- L Pezzoli
- R Elson
- C Little
- I Fisher
- H Yip
- T Peters
- M Hampton
- De Pinna
- E Coia
- J E Mather
- H A Brown
- D J Møller Nielsen
- E Ethelberg
- S Heck
- M Jager
- C Threlfall
Pezzoli, L., Elson, R., Little, C., Fisher, I., Yip, H., Peters, T., Hampton, M., De Pinna, E., Coia, J.E., Mather, H.A., Brown, D.J., Møller Nielsen, E., Ethelberg, S., Heck, M., de Jager, C., Threlfall, J., 2007. International outbreak of Sal-monella Senftenberg in 2007. URL: http://www.eurosurveillance.org/ew/ 2007/070614.asp. PHLS (Public Health Laboratory Service), 2000. Guidelines for the micro-biological quality of some ready-to-eat foods sampled at the point of sale. Communicable Disease and Public Health (CDPH) 3, 163–167.
Fruits and vegetables Compendium of Methods for the Microbiological Examination of Foods
- R E Brackett
- D F Splittstoesser
Brackett, R.E., Splittstoesser, D.F., 2001. Fruits and vegetables, In: Downes, F.P., Ito, K. (Eds.), Compendium of Methods for the Microbiological Examination of Foods, 4th ed. American Public Health Association, Washington D.C., pp. 515–520.
National Institute of Infectious Diseases and Infectious Diseases Control Division, Ministry of Health and Welfare of Japan), 1997. Verocytotoxin-producing Escherichia coli (enterohemorrhagic E. coli) infec-tion
- Nat
- Inst
Nat'l. Inst. Inf. Dis. (National Institute of Infectious Diseases and Infectious Diseases Control Division, Ministry of Health and Welfare of Japan), 1997. Verocytotoxin-producing Escherichia coli (enterohemorrhagic E. coli) infec-tion, Japan, 1996–1997.
Microbiological risk assessment on salads in Hong Kong
FEHD (Food and Environmental Hygiene Department, HKSAR), 2002.
Microbiological risk assessment on salads in Hong Kong. Risk Assessment Studies, Report no. 9. URL: http://fehd.gov.hk/safefood/report/salad/
report.pdf.
Spinach and E. coli outbreak
- Fda Food
- Drug Administration
FDA (Food and Drug Administration, USA), 2006. Spinach and E. coli
outbreak. URL: http://www.fda.gov/oc/opacom/hottopics/spinach.html.