Roles of oxidation-reduction potential in electrolyzed oxidizing and chemically modified water for the inactivation of food-related pathogens

Electric field-based air nanobubbles (EF-ANBs) irrigation on efficient crop cultivation with reduced fertilizer dependency

The advent of air nanobubbles (ANBs) has opened up a wide range of commercial applications spanning industries including wastewater treatment, food processing, biomedical engineering, and agriculture. The implementation of electric field-based air nanobubbles (EF-ANBs) irrigation presents a promising approach to enhance agricultural crop efficiency, concurrently promoting environmentally sustainable practices through reducing fertilizer usage. This study investigated the impact of EF-ANBs on the germination and overall growth of agricultural crops in soil. Results indicate a substantial enhancement in both germination rates and plant growth upon the application of EF-ANBs. Notably, the introduction of ANBs led to a significant enhancement in the germination rate of lettuce and basil, increasing from approximately 20% to 96% and from 16% to 53%, respectively over two days. Moreover, the presence of EF-ANBs facilitates superior hypocotyl elongation, exhibiting a 2.8- and a 1.6-fold increase in the elongation of lettuce and basil, respectively, over a six-day observation period. The enriched oxygen levels within the air nanobubbles expedite aerobic respiration, amplifying electron leakage from the electron transport chain (ETC) and resulting in heightened reactive oxygen species (ROS) production, playing a pivotal role in stimulating growth signaling. Furthermore, the application of EF-ANBs in irrigation surpasses the impact of traditional fertilizers, demonstrating a robust catalytic effect on the shoot, stem, and root length, as well as the leaf count of lettuce plants. Considering these parameters, a single fertilizer treatment (at various concentrations) during EF-ANBs administration, demonstrates superior plant growth compared to regular water combined with fertilizer. The findings underscore the synergistic interaction between aerobic respiration and the generation of ROS in promoting plant growth, particularly in the context of reduced fertilizer levels facilitated by the presence of EF-ANBs. This promising correlation holds significant potential in establishing more sustainability for ever-increasing environmentally conscious agriculture.

Bactericidal efficacy of lithium magnesium silicate hydrosol incorporated with slightly acidic electrolyzed water in disinfection application against Escherichia coli

In food safety implementation, bacterial inactivation is an imperative aspect of hygiene and sanitation. Studies on lithium magnesium silicate (LMS) hydrosol incorporated with slightly acidic electrolyzed water (SAEW) for decontamination of pathogenic bacteria are limited. This present study aimed to investigate the bactericidal efficacy of LMS hydrosol incorporated with SAEW against Escherichia coli. Optimum combination conditions of SAEW, hydrosol concentration, and available chlorine concentration (ACC) were optimized by response surface methodology under the central composite design against the growth of E. coli. The optimum combination conditions of exposure time, hydrosol concentration, and ACC were 9.5 minutes, 1.7%, and 20.5 ppm, respectively. The results showed that the increase in ACC led to inactivation in the survival of E. coli compared with the control (p<0.05). It can be concluded that the best combination percentage between SAEW and hydrosol ranged from 1.5-1.7%, in which E. coli was reduced by 4.50 log10 CFU/mL at an ACC of 9.94 ppm. When increasing the ACC to 14.84 ppm, E. coli was reduced by 4.51 log10 CFU/mL compared with the initial number of bacteria (8.20 log10 CFU/mL) in the control group. The number of bacteria was undetected after increasing ACC to 19.93, 25.15, and 29.88 ppm at 10 min. This study suggests that LMS hydrosol incorporated with SAEW could potentially be used as an effective sanitizer.

Effect of Slightly Acidic Electrolyzed Water on Growth, Diarrhea and Intestinal Bacteria of Newly Weaned Piglets

As an environmentally-friendly agent, slightly acidic electrolyzed water (SAEW) was introduced in drinking water of newly weaned piglets for diarrhea prevention. In total, 72 piglets were employed and 3% SAEW was added into the normal temperature and warm (30 °C) tap water, respectively, for this 33-day feeding experiment. It was found that the total bacteria and coliforms in the drinking water were reduced by 70% and 100%, respectively, with the addition of 3% SAEW. After SAEW treatment, the average daily water and feed intakes of piglets were increased during the first 16 days, and the diarrhea rate was reduced by 100%, with not one case of diarrhea recorded at the end of the experiment. The microbiome results demonstrated that SAEW decreased the diversity of caecum bacteria with normal tap water supplied, and increased the richness of the caecum bacteria with warm tap water supplied. SAEW also increased the abundance of potentially beneficial genera Sutterella and Ruminococcaceae_UCG-005 and reduced the abundance of pathogenic Faecalibacterium. Moreover, twelve metabolic functions belonging to the cluster of metabolism and organismal functions, including digestion and the endocrine and excretory systems, were greatly enhanced. Correlation analysis indicated that the influence of intestinal pathogens on water and feed intakes and the diarrhea of piglets were decreased by SAEW. The results suggest that SAEW can be used as an antibiotic substitute to prevent diarrhea in newly weaned piglets.

Neutral Electrolyzed Water in Chicken Breast-A Preservative Option in Poultry Industry

Chicken is one of the most consumed meats in the world because it is an economical protein source with a low fat content. Its conservation is important to maintain safety along the cold chain. In the present study, the effect of Neutral Electrolyzed Water (NEW) at 55.73 ppm was evaluated on contaminated chicken meat with Salmonella Typhimurium and Escherichia coli O157:H7, which was stored in refrigerated conditions. The present study was carried out to check whether the application of NEW can help to preserve chicken breasts without affecting its sensory characteristics. Chicken quality was measured by analyzing physicochemical properties (pH, color, lactic acid, total volatile basic nitrogen, and thiobarbituric acid reactive substances content) after bactericidal intervention. This work includes a sensory study to determine if its use affects the organoleptic properties of the meat. The results showed that in the in vitro assay, NEW and NaClO, achieved bacterial count reductions of >6.27 and 5.14 Log10 CFU for E. coli and Salmonella Typhimurium, respectively, even though, in the in situ challenge, they showed a bacterial decrease of 1.2 and 0.33 Log10 CFU/chicken breast in contaminated chicken breasts with E. coli and Salmonella Typhimurium, respectively, after 8 days of storage, and NaClO treatment did not cause bacterial reduction. Nonetheless, NEW and NaClO did not cause lipid oxidation and nor did they affect lactic acid production, and they also slowed meat decomposition caused by biogenic amines. Sensory results showed that chicken breast characteristics like appearance, smell, and texture were not affected after NEW treatment, and obtained results showed that NEW could be used during chicken meat processing due to the chicken physicochemical stability. However, more studies are still needed.

Suitability of air moisture oxidation-reduction potential as an indicator of atmospheric pollution

This Discussion article aimed to explore the measurement of oxidation-reduction potential (ORP) in air moisture as an index of air pollution that may offer advantages over other measurements. First, the concept of air quality and the definition of air pollution levels are examined. The methods and purpose of measuring pollution in air moisture are then briefly explained. The article then highlights a number of preliminary observations and results of in-progress research on the effects of ORP in air moisture on human physical sensations, plant vitality, and proliferation of microorganisms. Further, the implications of controlling air moisture ORP for human exposure and health are discussed. In conclusion, the preliminary evidence suggests that air moisture ORP holds great potential as an indicator of air pollution and that the modulation of the ORP value in the environment can improve thermal sensation in humans, enhance plant health, and prevent the proliferation of toxic microorganisms. Future research is warranted to confirm these observations.

Physical characterization and wound healing properties of Zamzam water

The objective of the study was to evaluate the quality of Zamzam water, holy water for Muslims and consumed for its medicinal value. The present study demonstrates the physicochemical characterization and wound healing property of Zamzam water. The physicochemical characterization of Zamzam water samples was analyzed for dissolved oxygen, pH, conductivity, total dissolved solids, redox potential, zeta potential, polydispersity index, and zeta size. The microbial quality of Zamzam water was also assessed by exposing water samples to open air. In this work, Zamzam water was also screened for the medicinal value through wound healing properties in Wistar rats. Zamzam water exhibited a unique physicochemical characterization with high levels of dissolved oxygen, zeta potential, polydispersity index, redox potential, total dissolved solids, and conductivity before exposure to open air. After open air exposure, Zamzam water resisted the growth of bacteria. The wound healing properties of Zamzam water in vivo showed a 96% of healing effect on 12th day observation. The wound healing was achieved by modulating pro-inflammatory cytokine such as interleukin -1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor -α (TNF-α). Followed by the level of apoptosis markers caspase-9 and caspase-3 were reduced. The present study proved that Zamzam water is a good-quality water and showed excellent wound healing property. Therefore, Zamzam water can be used for pharmaceutical formulations.

Effects of Individual and Block Freezing on the Quality of Pacific Oyster (Crassostrea gigas) during Storage under Different Pretreatment Conditions

In this study, a series of pretreatments, including ice-glazing, polyphosphate impregnated, and both ice-glazing and polyphosphate impregnated, were employed to pretreat shucked oysters in order to explore the optimal processing conditions for long-time storage. The effect of repeated freezing-thawing cycles on the quality of oysters was evaluated. Several quality indicators were used to investigate the effects of pretreatment. For the VBN (volatile salt-based nitrogen) value, the lowest value was 9.1 ± 0.2 of BPG (block oyster with polyphosphate impregnated and ice-glazing), which was significantly lower than 9.6 ± 0.2 of IPG (individual oyster with polyphosphate impregnated and ice-glazing). In terms of drip loss, there was no significant difference between the IPG (21.0 ± 0.2%) and the BPG (20.8 ± 0.2%). In addition, the highest WHC% (water holding capacity) was IPG (65.5 ± 0.5%) which was slightly lower than BPG (67.6 ± 0.6%). As compared to the experimental control, the IPG and BPG had the best appearance and color. In terms of TAPC (total aerobic plate count), with the increase of freezing storage time, each group showed a slight downward trend, but the difference was not statistically significant. After repeated freezing-thawing of block frozen oysters, there were significant differences in drip loss, WHC, and cooked taste with the increasing number of times, and there was a trend of deterioration (p < 0.05). Repeated freezing and thawing can seriously degrade the quality of oysters, so individual freezing (especially IPG) should be the most appropriate processing method.

Antiseptic Effects and Biosafety of a Controlled-Flow Electrolyzed Acid Solution Involve Electrochemical Properties, Rather than Free Radical Presence

Electrolyzed acid solutions produced by different methods have antiseptic properties due to the presence of chlorine and reactive oxygen species. Our aim was to determine whether a controlled-flow electrolyzed acid solution (CFEAS) has the ability to improve wound healing due to its antiseptic and antibiofilm properties. First, we demonstrated in vitro that Gram-negative and Gram-positive bacteria were susceptible to CFEAS, and the effect was partially sustained for 24 h, evidencing antibiofilm activity (p < 0.05, CFEAS-treated vs. controls). The partial cytotoxicity of CFEAS was mainly observed in macrophages after 6 h of treatment; meanwhile, fibroblasts resisted short-lived free radicals (p < 0.05, CFEAS treated vs. controls), perhaps through redox-regulating mechanisms. In addition, we observed that a single 24 h CFEAS treatment of subacute and chronic human wounds diminished the CFU/g of tissue by ten times (p < 0.05, before vs. after) and removed the biofilm that was adhered to the wound, as we observed via histology from transversal sections of biopsies obtained before and after CFEAS treatment. In conclusion, the electrolyzed acid solution, produced by a novel method that involves a controlled flow, preserves the antiseptic and antibiofilm properties observed in other, similar formulas, with the advantage of being safe for eukaryotic cells; meanwhile, the antibiofilm activity is sustained for 24 h, both in vitro and in vivo.

Efficacy of Slightly Acidic Electrolyzed Water for Inactivation of Cronobacter sakazakii and Biofilm Cells

ABSTRACT

The disinfection efficacy and mechanism of activity of slightly acidic electrolyzed water (SAEW) were investigated against Cronobacter sakazakii. Treatment with three concentrations of SAEW decreased C. sakazakii by 23 to 55% after 2 min. Propidium iodide uptake and scanning electron micrographs indicated that SAEW treatment damaged cell integrity and changed membrane permeability resulting in leakage of nucleic acids (109.7%), intercellular proteins (692.3%), and potassium ions (53.6%). The ability to form biofilms was also reduced. SAEW treatment reduced the activity of superoxide dismutase and catalase from 100.73 and 114.18 U/mg protein to 50.03 and 50.13 U/mg protein, respectively. Expression of C. sakazakii response regulator genes (katG, rpoS, phoP, glpK, dacC, and CSK29544_RS05515) was reduced, which blocked repair of osmotic stress-induced damage and inhibited biofilm formation. These findings provide insight into the effects of SAEW on bacterial genotype and phenotype.

HIGHLIGHTS

Postharvest processing of tree nuts: Current status and future prospects-A comprehensive review

Tree nuts are important economic crops and are consumed as healthy snacks worldwide. In recent years, the increasing needs for more efficient and effective postharvest processing technologies have been driven by the growing production, higher quality standards, stricter food safety requirements, development of new harvesting methods, and demand to achieve energy saving and carbon neutralization. Among all, the technologies related to drying, disinfection, and disinfestation and downstream processes, such as blanching, kernel peeling, and roasting, are the most important processes influencing the quality and safety of the products. These processes make up the largest contribution to the energy consumptions and environmental impacts stemming from tree nut production. Although many studies have been conducted to improve the processing efficiency and sustainability, and preserve the product quality and safety, information from these studies is fragmented and a centralized review highlighting the important technology advancements of postharvest processing of tree nuts would benefit the industry. In this comprehensive review, almonds, walnuts, and pistachios are selected as the representative crops of tree nuts. Current statuses, recent advances, and ongoing challenges in the scientific research as well as in the industrial processing practices of these tree nuts are summarized. Some new perspectives and applications of tree nut processing waste and by-products (such as the hulls and shells) are also discussed. In addition, future trends and research needs are highlighted. The material presented here will help both stakeholders and scientists to better understand postharvest tree nut processing and provide technological recommendations to improve the efficiency and sustainability, product quality and safety, and competitiveness of the industry.

Spatial disinfection potential of slightly acidic electrolyzed water

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.

Comparison of the SARS-CoV-2-inactivating activities of the differently manufactured hypochlorous acid water products with various pH

The use of effective disinfectants is a key method of controlling the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Hypochlorous acid water (HAW) has a broad spectrum of virucidal activities. We previously reported that acidic electrolyzed water, one of the HAW products, had potent SARS-CoV-2-inactivating activity and showed promise as a disinfectant. However, different manufacturing methods have produced several HAW products with various pH values. Here, we compared the SARS-CoV-2-inactivating activities of various HAW products. At sufficiently high volume and residual chlorine concentration (RCC), the HAW products inactivated SARS-CoV-2 efficiently regardless of pH or manufacturing method. However, although HAW products at pH 5.0-6.4 maintained high RCC and sustained virucidal activity for 21 days, the RCC rapidly decreased in HAW products at pH ≤ 3.0. Our results may guide in choosing appropriate HAW products for different usage situations.

Study of the Electro-Activation Process of Calcium Lactate, Calcium Ascorbate Solutions, and Their Equimolar Mixture: Assessment of Their Physicochemical Properties

The aim of this study was to prepare electro-activated solutions (EAS) from calcium lactate, calcium ascorbate, and an equimolar mixture of these two salts to obtain their corresponding acids and to study their physicochemical characteristics, in particular, pH, titratable acidity, pK _a, and antioxidant activity. Indeed, the solutions were electro-activated in a reactor comprising three compartments (anodic, central, and cathodic) separated by anionic and cationic exchange membranes, respectively. The electric current intensities used were set at 250, 500, and 750 mA for a maximum period of 30 min. In general, the EAS obtained at 750 mA for 30 min showed the lowest pH (2.16, 2.08, 1.94) and pK _a (3.13, 3.07, 2.90) values and the highest titratable acidity (0.107, 0.102, 0.109 mol/L) for calcium lactate, the mixture, and calcium ascorbate, respectively. In addition, the obtained results have demonstrated that the pH, titratable acidity, and pK _a of the EAS varied proportionally and significantly (p < 0.001) with the duration of the experiment and the intensity of the electric current applied. To evaluate the migration of calcium (Ca²⁺) between the central and the cathodic compartments of the reactor, the concentration of Ca²⁺ was determined especially in the cathodic section by inductively coupled plasma optical emission spectroscopy (ICP-OES). The results showed that the migration of Ca²⁺ varied proportionally with the electric current intensity. In this context, analysis by Fourier transform infrared (FTIR) spectroscopy, high-performance liquid chromatography (HPLC), and differential scanning calorimetry (DSC) have confirmed the production of lactic acid and ascorbic acid compared to standards. In addition, analysis by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging technique confirmed high antioxidant activities of >90 and >83% for calcium ascorbate and the mixture, respectively, in comparison to the standard ascorbic acid (85%). Overall, this research has clearly demonstrated the eventual potential of electro-activation to produce highly reactive organic acids from their conjugated salts. These EAS can become excellent antimicrobial and sporicidal agents in the food processing industry.

Electrolyzed Oxidizing Water and Its Applications as Sanitation and Cleaning Agent

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.

Global bibliometric meta-analytic assessment of research trends on microbial chlorine resistance in drinking water/water treatment systems

Chlorine is the commonest and cheapest disinfectant used in drinking water and wastewater treatment at household, municipal and industrial levels. However, the uprising of microbial chlorine resistance (MCR) pose critical public health hazard concerns; because, its potentiate exposure to difficult-to-treat resistant pathogens. Therefore, this study aimed at evaluating the burden of MCR in drinking water/wastewater treatment and distribution systems (DWWTDS) via science mapping of research productivity (authors, countries, institutions), thematic conceptual framework, disciplines, research networks and associated intellectual landscape. MCR data were mined from Scopus and Web of Science based on optimized algorithms with the root key term "chlorine* resistant*'' and analysed for pre-set indicator variables. Results revealed 1127 documents from 442 journals and 1430% average growth rate (AGR) of research articles from 2017 to 2019 on MCR. Country-wise, the USA (n = 299), China (n = 119), and Japan (n = 43) ranked in the 1st, 2nd, and 3rd positions respectively, among the top participating countries in MCR research. MCR research had considerable performance in public health and sustainable concern subjects namely, Environmental Sciences & Ecology, Engineering, Microbiology, Water Resources, Biotechnology & Applied Microbiology, Food Science & Technology, Public, Environ & Occupational Health, Chemistry, Infectious Diseases, and Marine & Freshwater Biology; and with noticeable AGR in Environmental Sciences & Ecology (330%) and Infectious Diseases (130%). The study found biofilm-related thrusts (n = 90, 270% AGR) as main research hotspots on MCR. Overall, the study identified and discussed four important thematic areas of public health challenges in MCR that could promote increasing waterborne diseases due to (re)emerging pathogens, enteric viruses and dissemination in DWWTDS. In conclusion, this study provides comprehensive overview of the growing burden of MCR in DWWTDS and standout as a primer of information for researchers on MCR. It recommends direct, intentional and integrated research priorities on MCR to overcome accompanying public health and environmental threats. In addition, chlorine resistance in waterborne fungi have not received research attention. Research activities related to fungal chlorine resistance will be an invaluable future direction in DWWTDS and guide against exposure to waterborne pathogenic fungi and mycotoxins. It is unknown whether chlorine resistance can be acquired by horizontal gene transfer in microorganisms and future research should elucidate this important thrust.

Atomic force microscopy in food preservation research: New insights to overcome spoilage issues

A higher level of food safety is required due to the fast-growing human population along with the increased awareness of healthy lifestyles. Currently, a large percentage of food is spoiled during storage and processing due to enzymes and microbial activity, causing huge economic losses to both producers and consumers. Atomic force microscopy (AFM), as a powerful scanning probe microscopy, has been successfully and widely used in food preservation research. This technique allows a non-invasive examination of food products, providing high-resolution images of surface structure and individual polymers as well as the physical properties and adhesion of single molecules. In this paper, detailed applications of AFM in food preservation are reviewed. AFM has been used to provide comprehensive information in food preservation by evaluating the spoilage with its related structure modification. By utilizing AFM imaging and force measurement function, the main mechanisms involved in the loss of food quality and preservation technologies development can be further elucidated. It is also capable of exploring the activities of enzymes and microbes in influencing the quality of food products during storage. AFM provides comprehensive solutions to overcome spoilage issues with its versatile functions and high-throughput outcomes. Further research and development of this novel technique in order to solve integrated problems in food preservation are necessary.

Optimization and Modeling of Slightly Acidic Electrolyzed Water for the Clean-in-Place Process in Milking Systems

To find an environmentally friendly and energy efficient alternative to acidic detergent for a milking system clean-in-place (CIP) process, this study investigated the feasibility of applying slightly acidic electrolyzed water (SAEW) alone to wash the system by cleaning soiled stainless steel (304) pipes, rubber gaskets, and PVC milk hoses, which were used in the milking system. The results showed that SAEW with appropriate parameters could achieve the same or even better hygienic effects compared with commercial detergent. Using response surface models, the SAEW parameters required to clean stainless steel were optimized at 9.9 min for the treatment time, 37.8 °C for the water temperature, and 60 mg/L for the available chlorine concentration; and were 14.4 min, 29.6 °C, and 60 mg/L for rubber gasket and PVC samples, respectively. After washing with the optimized parameter combination, bacteria and adenosine triphosphate on the three materials were almost non-detectable, indicating that SAEW has the potential to replace acidic detergents in CIP milking systems.

Evaluation of the effect of neutral electrolyzed water and peroxyacetic acid alone and in combination on microbiological, chemical, and sensory characteristics of poultry meat during refrigeration storage

The objectives of this study were to evaluate the efficacy of near-neutral electrolyzed water (NEW) (100 and 200 µg/ml), peroxyacetic acid (PAA) (200 and 400 µg/ml), and their combination (NEW 100 µg/ml + PAA 200 µg/ml) on microbial quality, pH, TBARS value, and sensory quality of fresh chicken breast meat dipped into the solutions for 10 min at room temperature. Meat samples were tested immediately after treatments and on days 2, 4, and 6 of storage at 4℃. All treatments were effective in reducing microbial populations throughout the storage (P < 0.05), with combined treatment showing the strongest antimicrobial activity. On the sixth day of storage, the aerobic plate counts, psychrophilic plate count, Enterobacteriaceae, lactic acid bacteria, and Pseudomonas counts in the NEW 100 µg/ml + PAA 200 µg/ml group were 1.33, 1.40, 1.45, 1.01, and 1.45 log CFU/g, respectively, which was lower than the control group (P < 0.05). In all treatments, the pH value of meat samples increased with storage time. During 6 days of storage, PAA400 group had the lowest increase in pH value (P < 0.05). On day 6, the combined treatment and PAA 400 µg/ml had the lowest lipid oxidation (P < 0.05). On day 6, the NEW100 + PAA200 group obtained the highest score in sensory attributes compared to other treatment groups (P < 0.05). According to the microbial and chemical analysis, the combined treatment of NEW and PAA can be a promising method to extend the shelf life of chicken by about 2 days at 4℃. Also, these compounds do not contain any harmful residues in chicken breast meat and their use is recommended in decontamination of poultry meat.

Comparison of Inactivation Effect of Slightly Acidic Electrolyzed Water and Sodium Hypochlorite on Bacillus cereus Spores

Bacillus cereus spores are concerns for food spoilage and foodborne disease in food industry due to their high resistance to heat and various disinfectants. The aim of this study was to investigate the inactivation of B. cereus spores by slightly acidic electrolyzed water (SAEW) in comparison to sodium hypochlorite (NaClO) with same available chlorine content (ACC). In this study, the efficacy of SAEW with different concentrations of ACC (40, 60, 80, 100, and 120 mg/L) on the inactivation of B. cereus spores, and the effect of SAEW combined with mild heat treatment (60°C), was examined in pure culture suspensions. Heat resistance and pyridine-2,6-dicarboxylic acid (DPA) release of the spores were also determined. The results showed that the sporicidal effect of the SAEW was significantly higher compared with the NaClO with the same concentration of ACC. Furthermore, the inactivation efficacy was largely dependent on ACC and treatment time. Moreover, the sporicidal activity of the SAEW was significantly improved when combined with a mild heat treatment (60°C). The majority of the DPA was released from spores, and the spores exhibited less resistance to heat after SAEW treatment for 30 min. These findings indicate that SAEW could effectively inactivate B. cereus spores, making it a promising and environmentally friendly decontamination technology for application in the food industry.

Microbes associated with fresh produce: Sources, types and methods to reduce spoilage and contamination

Global food security remains one of the most important challenges that needs to be addressed to ensure the increasing demand for food of the fast growing human population is satisfied. Fruits and vegetables comprise an essential component of a healthy balanced diet as they are the major source of both macro- and micronutrients. They are particularly important for communities in developing countries whose nutrition often relies solely on a plant-based diet. Recent advances in agriculture and food processing technologies have facilitated production of fresh, nutritious and safe food for consumers. However, despite the development of sophisticated chemical and physical methods of food and equipment disinfection, fresh-cut produce and fruit juice industry still faces significant economic losses due to microbial spoilage. Furthermore, fresh produce remains an important source of pathogens that have been causing outbreaks of human illness worldwide. This chapter characterizes common spoilage and human pathogenic microorganisms associated with fresh-cut produce and fruit juice products, and discusses the methods and technology that have been developed and utilized over the years to combat them. Substantial attention is given to highlight advantages and disadvantages of using these methods to reduce microbial spoilage and their efficacy to eliminate human pathogenic microbes associated with consumption of fresh-cut produce and fruit juice products.

Influence of water antimicrobials and storage conditions on inactivating MS2 bacteriophage on strawberries

Foodborne illnesses caused by norovirus contaminated fresh produce remain a food safety concern worldwide. In the present study, the impacts of commercial and home processing conditions of strawberries were evaluated for inactivation of the MS2 bacteriophage. MS2 was used as a surrogate of norovirus and was spot inoculated onto strawberries to achieve 6.6 log PFU/g. The inoculated strawberries were washed with tap water, electrolyzed water, or 50 ppm chlorine for 90 s prior to and after storage. After initial washing, the strawberries were separately stored at -20 °C and -80 °C for 30 days. Change in MS2 populations on strawberries was evaluated by plaque assay method on day 1, 15, and 30 for -20 °C and -80 °C groups. The results showed that washing strawberries prior to storage resulted in a significant decrease (approximately 1 log PFU/g) of MS2 population regardless of the treatment (p < 0.05). Frozen storage had minor effects on inactivating MS2, which resulted in approximately a 0.5 log PFU/g reduction at the end of storage. Washing frozen berries in electrolyzed water or 50 ppm chlorine on day 30 resulted in an additional 1 log PFU/g decrease in MS2 compared to water alone. These results suggest that washing strawberries with a chemical antimicrobial prior to and post frozen storage may enhance microbial safety.

Removal of Foodborne Pathogen Biofilms by Acidic Electrolyzed Water

Biofilms, which are complex microbial communities embedded in the protective extracellular polymeric substances (EPS), are difficult to remove in food production facilities. In this study, the use of acidic electrolyzed water (AEW) to remove foodborne pathogen biofilms was evaluated. We used a green fluorescent protein-tagged Escherichia coli for monitoring the efficiency of AEW for removing biofilms, where under the optimal treatment conditions, the fluorescent signal of cells in the biofilm disappeared rapidly and the population of biofilm cells was reduced by more than 67%. Additionally, AEW triggered EPS disruption, as indicated by the deformation of the carbohydrate C-O-C bond and deformation of the aromatic rings in the amino acids tyrosine and phenylalanine. These deformations were identified by EPS chemical analysis and Raman spectroscopic analysis. Scanning electron microscopy (SEM) images confirmed that the breakup and detachment of biofilm were enhanced after AEW treatment. Further, AEW also eradicated biofilms formed by both Gram-negative bacteria (Vibrio parahaemolyticus) and Gram-positive bacteria (Listeria monocytogenes) and was observed to inactivate the detached cells which are a potential source of secondary pollution. This study demonstrates that AEW could be a reliable foodborne pathogen biofilm disrupter and an eco-friendly alternative to sanitizers traditionally used in the food industry.

Sanitizer efficacy in preventing cross-contamination of heads of lettuce during retail crisping

This study was conducted to provide information regarding mitigation of cross-contamination through the use of sanitizer during crisping at retail outlets. Seven non-inoculated heads and one inoculated head (≈5 log CFU/g) of lettuce were placed into commercial sink filled with 76 L of tap water (TW), electrolyzed water (EW, free chlorine: 43 ± 6 ppm), lactic acid and phosphoric acid-based sanitizer (LPA, pH 2.89), or citric acid-based sanitizer (CA, pH 2.78) and soaked for 5 min. Two subsequent batches (eight non-inoculated heads per batch) were soaked in the same solution. Soaking with EW significantly reduced the population of S. enterica (2.8 ± 1.5 log CFU/g), E. coli O157:H7 (3.4 ± 1.1 log CFU/g), and L. monocytogenes (2.6 ± 0.7 log CFU/g) inoculated on Romaine lettuce compared to TW, LPA, and CA (p < 0.05). On Red leaf lettuce, EW significantly reduced populations of S. enterica and E. coli O157:H7, but not L. monocytogenes compared to other treatments. No significant difference was noted between TW, LPA, and CA in reducing foodborne pathogens (p > 0.05) or preventing cross-contamination. Soaking with EW prevented cross-contamination among lettuce heads and controlled bacterial populations in crisping water for three consecutive batches. EW may be an effective option as a sanitizer to minimizing the cross-contamination of leafy greens during the retail crisping.

Cytotoxicity, Bactericidal, and Antioxidant Activity of Sodium Alginate Hydrosols Treated with Direct Electric Current

The aim of the study was to investigate the effect of using direct electric current (DC) of 0, 200, and 400 mA for five minutes on the physiochemical properties, cytotoxicity, antibacterial, and antioxidant activity of sodium alginate hydrosols with different sodium chloride concentrations. The pH, oxidation-reduction potential (ORP), electrical conductivity (EC), and available chlorine concentration (ACC) were measured. The effect of sodium alginate hydrosols treated with DC on Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Micrococcus luteus, Escherichia coli, Salmonella enteritidis, Yersinia enterocolitica, Pseudomonas fluorescence, and RAW 264.7 and L929 cells was investigated. Subsequently, the antioxidant properties of hydrosols were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and ferric reducing antioxidant power (FRAP). The results have shown that after applying 400 mA in hydrosol samples with 0.1% and 0.2% NaCl all tested bacteria were inactivated. The ACC concentration of C400 samples with NaCl was equal to 13.95 and 19.71 mg/L, respectively. The cytotoxicity analysis revealed that optimized electric field conditions and the addition of sodium chloride allow for the avoidance of toxicity effects on normal cells without disturbing the antibacterial effects. Due to the presence of oxidizing substances, the DPPH of variants treated with DC was lower than the DPPH of control samples.

Effectiveness of Neutral Electrolyzed Water on Incidence of Fungal Rot on Tomato Fruits ( Solanum lycopersicum L.)

We assessed the effect of neutral electrolyzed water (NEW) on the incidence of rot on tomato ( Solanum lycopersicum L.) fruits inoculated with Fusarium oxysporum , Galactomyces geotrichum , and Alternaria sp. at sites with lesions. The inoculated fruits were treated with NEW at 10, 30, and 60 mg liter^-1 active chlorine, with copper oxychloride fungicide, and with sterile distilled water (control) for 3, 5, and 10 min. In the experiment with F. oxysporum , 50 to 80% of the control fruits and 50 to 60% of the fruits treated with the fungicide exhibited symptoms of rot at the inoculated sites. The lowest incidence recorded was 30% for fruits treated with NEW at 60 mg liter^-1 active chlorine with an immersion time of 5 min. In the experiment with G. geotrichum , incidence of rot on control fruits was 70 to 90%, and for treatment with fungicide rot incidence was 50 to 90%. NEW at 60 mg liter^-1 active chlorine significantly reduced incidence of symptomatic fruit: only 30% of the inoculated fruits washed for 5 min had damage from rot. In the experiment with Alternaria sp., 60 to 90% of the fruits in the control group and 60 to 70% of the fruits in the fungicide group were symptomatic. The lowest incidence was recorded for the treatment in which the fruits were submerged in NEW with 60 mg liter^-1 active chlorine for 3 min. In this group, 40 to 50% of the fruits exhibited symptoms of rot. These results were obtained 8 days after inoculation. NEW, with 60 mg liter^-1 active chlorine, significantly reduced incidence of rot symptoms on fruits inoculated with one of the experimental fungi relative to the control (P ≤ 0.05). NEW at 60 mg liter^-1 is effective in the control of fungal rot in tomatoes.

Use of electrochemically activated aqueous solutions in the manufacture of fur materials

The influence of characteristics of electrochemically activated aqueous processing mediums in the treatment of fur skins with different contents of fatty substances was investigated. The use of electroactive water, namely anolytes and catholytes, forgoing antiseptics or surface-active materials, helped to restore the hydration of fur skins and to remove from them soluble proteins, carbohydrates and fatty substances. The activating effect of anolyte and catholyte in solutions of water on the processes of treating raw furs is explained by their special physical and chemical properties, namely the presence of free radicals, ions and molecules of water which easily penetrate cells' membranes and into the structure of non-collagen components and microfiber structure of dermic collagen. The stage of lengthy acid and salt treatment is excluded from the technical treatment as a result of using electroactivated water with high oxidizing power. A low-cost technology of processing different kinds of fur with the use of electroactivated water provides for substantial economy of water and chemical reagents, a two to threefold acceleration of the soaking and tanning processes and creation of highly elastic fur materials with a specified set of physical and chemical properties. At the same time the technology of preparatory processes of fur treatment excludes the use of such toxic antiseptics as formalin and sodium silicofluoride, which gives grounds to regard it as ecologically safe.

Differential proteomics to explore the inhibitory effects of acidic, slightly acidic electrolysed water and sodium hypochlorite solution on Vibrio parahaemolyticus

Slightly acidic electrolysed water (SlAEW) and acidic electrolysed water (AEW) have been demonstrated to effectively inactivate food-borne pathogens. However, the underlying mechanism of inactivation remains unknown. Therefore, in this study, a differential proteomic platform was used to investigate the bactericidal mechanism of SlAEW, AEW, and sodium hypochlorite (NaOCl) solutions against Vibrio parahaemolyticus. The upregulated proteins after SlAEW, AEW, and NaOCl treatments were identified as outer membrane proteins K and U. The downregulated proteins after the SlAEW, AEW, and NaOCl treatments were identified as adenylate kinase, phosphoglycerate kinase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and enolase, all of which are responsible for energy metabolism. Protein synthesis-associated proteins were downregulated and identified as elongation factor Tu and GAPDH. The inhibitory effects of SlAEW and AEW solutions against V. parahaemolyticus may be attributed to the changes in cell membrane permeability, protein synthesis activity, and adenosine triphosphate (ATP) biosynthesis pathways such as glycolysis and ATP replenishment.