Antimicrobial effect of electrolyzed water for inactivating Campylobacter jejuni during poultry washing

Interventions to reduce Salmonella and Campylobacter during chilling and post-chilling stages of poultry processing: a systematic review and meta-analysis

Salmonella and Campylobacter are common bacterial hazards causing foodborne illnesses worldwide. A large proportion of Salmonella and Campylobacter illnesses are attributed to contaminated poultry products that are mishandled or under cooked. Processing interventions such as chilling and post-chill dip are critical to reducing microbial contamination of poultry. A comprehensive search of the literature published between 2000 and 2021 was conducted in the databases Web of Science, Academic Search Complete, and Academic OneFile. Studies were included if they were in English and investigated the effects of interventions against Salmonella and/or Campylobacter on whole carcasses and/or parts during the chilling or post-chill stages of poultry processing. Random-effects meta-analyses were performed using the "meta" package in the R programming language. Subgroup analyses were assessed according to outcome measure reported, microorganism tested, processing stage assessed, and chemical treatment used. The results included 41 eligible studies. Eighteen studies reported results of 28 separate interventions against Salmonella and 31 reported results of 50 separate interventions against Campylobacter. No significant difference (P> 0.05) was observed when comparing the combined mean difference of all interventions targeting Salmonella to the combined mean difference of all interventions targeting Campylobacter or when comparing chilling times within each pathogen subgroup. For analyses examining antimicrobial additives, peroxyacetic acid (PAA) had the largest reduction against Salmonella population regardless of chilling time (P< 0.05). PAA also had the largest reduction against Campylobacter population and prevalence during primary chilling (P< 0.01). Air chilling showed a lower reduction for Campylobacter than any immersion chilling intervention (P< 0.05). Chilling time and antimicrobial used during poultry processing had varying effects depending on the pathogen and outcome measure investigated (concentration or prevalence). High heterogeneity and low sample numbers in most analyses suggest that more high-quality research that is well-designed and has transparent reporting of methodology and results is needed to corroborate the results.

Comparative evaluation of alkaline ionized water and normal water on oral microbial flora: An in-vitro study

Background

Various artificial chemical agents have been evaluated over many years with respect to their antimicrobial effect in oral cavity. The gold standard for removal of plaque is usage of chlorhexidine, but it can cause alteration in taste sensation and staining of teeth. Electrolytes and oxidizing water may be useful against microbes, but its clinical application has still not been evaluated. Hence this present study was conducted to evaluate the effectiveness of the alkaline ionized water on oral microbial flora.

Materials and Methods

Ten non-carious, un-restored and intact freshly extracted human teeth were collected and sectioned using a round bur. Each tooth was sectioned longitudinally in two parts and stored in closed sterile containers which was filled with alkaline ionized water (Group 1) and normal water (Group 2), respectively for 15 days. The microbial growth was analyzed prior to dipping in the solutions, 3 days, 7 days and 15 days. The pH of alkaline ionized water and normal water was evaluated using pH meter before placing teeth in different solutions. Results were analyzed using t-test and the level of significance was set at ≤ 0.05.

Results

No difference in bacterial colony was observed before test and after 3 days among Group 1 and Group 2, respectively. After 7 days and 15 days, statistically significant decrease in bacterial colony count was seen among Group 1 as compared to Group 2 (P ≤ 0.05).

Conclusion

It was then concluded that alkaline ionized water can be effective in reduction of oral microbial flora.

Effect of Slightly Acidic Electrolyzed Water Immersion at Different Frequencies on Quality of Raw Chicken Legs

Slightly acidic electrolyzed water (SAEW) is used as a disinfectant for raw chicken meat. Because its volume for a single immersion exceeds 10 times the weight of meat, a large amount of wastewater is generated. Importantly, a higher frequency of immersion is believed to reduce microbial contamination. The objective of this study was to investigate the effect of SAEW immersion at different frequencies on the disinfection and quality of raw chicken legs, thereby possibly limiting the usage of SAEW. Immersion for 1, 3, and 5 times, with a 7:1 SAEW:meat ratio, and duration of 15 min was tested. Meat quality was evaluated based on total aerobic bacteria, Enterobactericeae, total volatile basic nitrogen, thiobarbituric acid reactive substances, and color. A higher immersion frequency lowered the numbers of total aerobic bacteria and Enterobacteriaceae. Moreover, two immersions with a SAEW:meat ratio of 4:1 and a total immersion time of 6 min reduced the bacterial load as effectively as a single 15-min immersion with a SAEW:meat ratio of 7:1. Higher frequencies of SAEW immersion also resulted in lower total volatile basic nitrogen and lipid oxidation after 0 or 3 days of storage. They did, however, magnify the change in color, resulting in brighter meat. Overall, SAEW treatments with two to five immersions can improve the quality of raw chicken legs and reduce wastewater generation.

A systematic review and meta-analysis of the efficacy of processing stages and interventions for controlling Campylobacter contamination during broiler chicken processing

Systematic review and meta-analysis were conducted to quantify the effects of processing stages and interventions on the prevalence and concentration of Campylobacter on broiler carcasses. To comprehensively capture relevant evidence, six databases were searched using the keywords "Campylobacter" and "broiler chicken." The literature search yielded 10,450 unique citations, and after applying predetermined inclusion and exclusion criteria, 72 and 53 relevant citations were included in meta-analyses for processing stages and interventions, respectively. As the two primary outcomes, log reduction and prevalence changes were estimated for each stage or intervention using a random-effects meta-analysis approach whenever possible. The outcome-level quality assessment was conducted following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. The analysis revealed that scalding and chilling majorly reduces the prevalence and concentration of Campylobacter. Immersion chilling reduces the concentration regardless of chemical additives, but its effect on prevalence is not conclusive. The effects of carcass washing applications remain uncertain due to the inconsistency and imprecision of both outcomes. Defeathering and evisceration were identified as stages that can increase both prevalence and concentration. Both chemical and physical processing interventions provide limited efficacy in concentration and prevalence reduction. Major limitations of the review were inconsistency and imprecision at the outcome level and reporting issues and data gaps at the study level. The results are expected to inform quantitative microbial risk assessment model development and support evidence-based decision-making.

Mapping foodborne pathogen contamination throughout the conventional and alternative poultry supply chains

Recently, there has been a consumer push for natural and organic food products. This has caused alternative poultry production, such as organic, pasture, and free-range systems, to grow in popularity. Due to the stricter rearing practices of alternative poultry production systems, different types of levels of microbiological risks might be present for these systems when compared to conventional production systems. Both conventional and alternative production systems have complex supply chains that present many different opportunities for flocks of birds or poultry meat to be contaminated with foodborne pathogens. As such, it is important to understand the risks involved during each step of production. The purpose of this review is to detail the potential routes of foodborne pathogen transmission throughout the conventional and alternative supply chains, with a special emphasis on the differences in risk between the two management systems, and to identify gaps in knowledge that could assist, if addressed, in poultry risk-based decision making.

The Data Behind Risk Analysis of Campylobacter Jejuni and Campylobacter Coli Infections

Campylobacter jejuni and Campylobacter coli are major causes of food-borne enteritis in humans. Poultry meat is known to be responsible for a large proportion of cases of human campylobacteriosis. However, other food-borne, environmental and animal sources are frequently associated with the disease in humans as well. Human campylobacteriosis causes gastroenteritis that in most cases is self-limiting. Nevertheless, the burden of the disease is relatively large compared with other food-borne diseases, which is mostly due to rare but long-lasting symptoms related to immunological sequelae. In order to pave the way to improved surveillance and control of human campylobacteriosis, we review here the data that is typically used for risk analysis to quantify the risk and disease burden, identify specific surveillance strategies and assist in choosing the most effective control strategies. Such data are mostly collected from the literature, and their nature is discussed here, for each of the three processes that are essential for a complete risk analysis procedure: risk assessment, risk management and risk communication. Of these, the first, risk assessment, is most dependent on data, and this process is subdivided into the steps of hazard identification, hazard characterization, exposure assessment and risk characterization. For each of these steps of risk assessment, information from published material that is typically collected will be summarized here. In addition, surveillance data are highly valuable for risk assessments. Different surveillance systems are employed in different countries, which can make international comparison of data challenging. Risk analysis typically results in targeted control strategies, and these again differ between countries. The applied control strategies are as yet not sufficient to eradicate human campylobacteriosis. The surveillance tools of Campylobacter in humans and exposure sources in place in different countries are briefly reviewed to better understand the Campylobacter dynamics and guide control strategies. Finally, the available control measures on different risk factors and exposure sources are presented.

Application of Neutral Electrolyzed Water on pork chops and its impact on meat quality

Physicochemical and microbiological properties of pork chops sprayed with Neutral Electrolyzed Water (NEW) were evaluated during storage at refrigeration temperature. Pork chops were randomly allocated into three groups and were artificially contaminated with an inoculum of 10⁶ CFU/mL of Listeria monocytogenes. Each group was treated with either NEW (58 ppm), NaClO (35 ppm), or saline solution (SS). Subsequently, recovered bacteria were plated on TSA petri dishes and the reduction percentage of Listeria monocytogenes was calculated 24 h and 8 days after treatment. Physicochemical analysis [pH, content of lactic acid, thiobarbituric acid reactive substances (TBARS) and total volatile base nitrogen (TVBN)] were performed to evaluate the effect of all solutions used on pork meat kept at 4 °C for 19 days. In vitro NEW reduced L. monocytogenes titers by > 99.98% and 80.19% and 90.35% in artificially contaminated pork 24 h and 8 days after NEW treatment, respectively. Compared to the SS treatment, NEW and NaClO solutions caused a 0.67 Log UFC/g and 0.65 Log UFC/g reduction respectively. After eight days post-treatment, NEW and NaClO bacterial titers were below the SS treatment. NEW caused little color change in treated meat. It helped to reduce the formation of lactic acid and TVB-N when pork chops are kept at 4 °C for 19 days. Therefore, NEW could be considered as a new alternative to sanitize and preserve pork meat.

Effect of Storage Conditions on Shelf Stability of Undiluted Neutral Electrolyzed Water

ABSTRACT

Neutral electrolyzed water (NEW) is an oxidizing sanitizer that can be made locally on-site; it is often stored in a ready-to-use format to accumulate the large volumes required for periodic or seasonal use. The shelf stability of NEW sanitizer was, therefore, assessed under various storage conditions to guide the development of protocols for its industrial application. To that end, fresh NEW with an available chlorine concentration (ACC) of 480 mg/L, pH 6.96, and oxidation reduction potential (ORP) of 916 mV was stored under different conditions. These were open or sealed polypropylene bottles, three different surface area-to-volume (SA:V) ratios (0.9, 1.7, and 8.7), and two temperatures (4 and 25°C). NEW stored at 4°C was significantly more stable than NEW stored at 25°C; ACC and pH decreased by 137 mg/L and 0.7, respectively, whereas ORP increased by 23 mV, after 101 days of storage. At 25°C, ACC decreased to <0.01 mg/L after 52 days in bottles with a SA:V ratio of 8.7, with a similar decrease after 101 days in bottles with a SA:V ratio of 1.7. However, pH decreased by up to 3.7 pH units, and ORP increased by up to 208 mV. The antimicrobial efficacy of "aged" electrolyzed oxidizing (EO) water with different ACC and ORP, but the same pH (i.e., 3.4 ± 0.2), was evaluated against Escherichia coli and Listeria innocua to determine any differences in residual antimicrobial activity. EO water with an ACC of ≥7 mg/L and an ORP of 1,094 mV caused a reduction of at least 4.7 log, whereas EO water with nondetectable ACC and considerably high ORP (716 mV) had little antimicrobial effect (<1-log reduction). Results from this study indicate that the efficacy of NEW as a sanitizer for large-scale applications such as horticulture can be maintained for at least 3 months when it is stored in closed containers with low SA:V ratio at low temperatures.

HIGHLIGHTS

Applications of Electrolyzed Water as a Sanitizer in the Food and Animal-By Products Industry

Food demand is increasing every year and, usually animal-derived products are generated far from consumer-places. New technologies are being developed to preserve quality characteristics during processing and transportation. One of them is electrolyzed water (EW) that helps to avoid or decrease the development of foodborne pathogens, or losses by related bacteria. Initially, EW was used in ready-to-eat foods such as spinach, lettuce, strawberries, among others; however, its application in other products is under study. Every product has unique characteristics that require an optimized application of EW. Different sanitizers have been developed; unfortunately, they could have undesirable effects like deterioration of quality or alterations in sensory properties. Therefore, EW is gaining popularity in the food industry due to its characteristics: easy application and storage, no corrosion of work surfaces, absence of mucosal membrane irritation in workers handling food, and it is considered environmentally friendly. This review highlights the advantages of using EW in animal products like chicken, pork, beef, eggs and fish to preserve their safety and quality.

Efficacy of peroxy acetic acid in reducing Salmonella and Campylobacter spp. populations on chicken breast fillets

Poultry processors use antimicrobials to reduce the risk of pathogens on poultry and poultry products. The efficacy of selective and nonselective plating media to enumerate injured Salmonella (selective media-brilliant green sulfa agar and Petrifilm Enterobacteriaceae Plate Count; nonselective media-tryptic soy agar and Petrifilm Aerobic Plate Count) and Campylobacter (selective medium-Campy cefex agar and nonselective medium-Brucella agar) populations and the efficacy of peroxy acetic acid (PAA) to reduce Salmonella and Campylobacter populations on chicken breast fillets were evaluated. All plating media for Salmonella and Campylobacter contained nalidixic acid (200 ppm) or gentamycin (200 ppm), respectively. Breast fillets were sprayed or immersed in PAA (500 ppm) for 10 min for evaluation of the plating media. Breast fillets inoculated with a mixed Salmonella and Campylobacter cocktail were sprayed (5 or 10 s) or immersed (4-30 s) in PAA (100, 400, 500, or 1,000 ppm) for evaluation of PAA efficacy. Salmonella populations were higher (P ≤ 0.05) when plated on nonselective media compared with the selective media for the non-PAA treated fillets, although the differences in populations were low (<0.32 log CFU/mL). For both the microorganisms, populations on PAA treated (immersion or spray) fillets were similar when enumerated on nonselective or selective media within each treatment (PAA immersion or spray). Both immersion and spray applications reduced (P ≤ 0.05) the Salmonella and Campylobacter populations compared with the control. Increasing the PAA concentration to 250, 500, and 1,000 ppm resulted in greater reductions (P ≤ 0.05) in Salmonella and Campylobacter populations. Immersion of the inoculated breast fillets in 1,000 ppm PAA solution for 30 s resulted in Salmonella and Campylobacter population reductions of 1.92 and 1.87 log CFU/mL, respectively. Method of antimicrobial application (immersion and spray) did not affect the reductions in Salmonella and Campylobacter populations. Either immersion or spray application can be used to improve microbial safety of chicken breast fillets in a poultry processing plant.

Functionalization of water as a nonthermal approach for ensuring safety and quality of meat and seafood products

Meat and seafood products present a viable medium for microbial propagation, which contributes to foodborne illnesses and quality losses. The development of novel and effective techniques for microbial decontamination is therefore vital to the food industry. Water presents a unique advantage for large-scale applications, which can be functionalized to inactivate microbial growth, ensuring the safety and quality of meat and seafood products. By taking into account the increased popularity of functionalized water utilization through electrolysis, ozonation and cold plasma technology, relevant literature regarding their applications in meat and seafood safety and quality are reviewed. In addition, the principles of generating functionalized water are presented, and the safety issues associated with their uses are also discussed.Functionalization of water is a promising approach for the microbiological safety and quality of meat and seafood products and possesses synergistic effects when combined with other decontamination approaches. However, functionalized water is often misused since the active antimicrobial component is applied at a much higher concentration, despite the availability of applicable regulations. Functionalized water also shows reduced antimicrobial efficiency and may produce disinfection by-products (DBPs) in the presence of organic matter, especially at a higher concentration of active microbial component. Utilization should be encouraged within regulated guidelines, especially as hurdle technology, while plasma functionalized water which emerges with great potentials should be exploited for future applications. It is hoped that this review should encourage the industry to adopt the functionalized water as an effective alternative technique for the food industry.

Influence of the acidity of electrolyzed water on the microhardness of inner layer dentin

Background/purpose

Electrolyzed water has been identified as an effective disinfectant that could represent as an alternative to sodium hypochlorite. Unfortunately, it remains unclear whether the texture or physical properties of dentin are affected by the application of electrolyzed water of different acidities. This study was aimed to assess the influence of electrolyzed waters with differing pHs on the demineralizing of inner dentin.

Materials and methods

The coronal superficial dentin of 20 human molars was exposed and further bisected into two pieces perpendicular to the dentin surface. The samples were immersed in strongly acidic electrolyzed water (AW group), neutral electrolyzed water (NW group), 5% sodium hypochlorite (positive control, NL group), or deionized water (negative control, DW group). Microhardness of the inner layer dentin was measured at a depth of 25 and 50 μm beneath the superficial surface layer every 5 up to 60 min.

Results

At a depth of 25 μm, microhardness decreased with increasing immersion time in all but the DW group. The AW group exhibited a decreasing trend from the first 5 min that became significant after 35 min of immersion and was the most rapid decrease in the four groups. The rate of decline in the NW group was low and similar to that of the NL group. Both NW and NL groups exhibited significantly less demineralization than the AW group after 15 min of immersion. No significant microhardness change was found at a depth of 50 μm in any of the samples.

Conclusion

AW produces a more pronounced softening of dentin than NW at a depth of 25 μm.

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.

Effects of slightly acidic electrolyzed water on the microbial quality and shelf life extension of beef during refrigeration

Studies on slightly acidic electrolyzed water (SAEW) for decontamination and shelf life extension of beef are limited. This study aimed to evaluate the effects of SAEW and tea polyphenols (Tpp) on the microbiological, physicochemical, and sensory qualities of fresh beef during storage. The changes in total viable count, thiobarbituric acid content, pH, total volatile basic nitrogen, and sensory scores revealed that the required quality standard of the beef treated with distilled water, Tpp, and SAEW was maintained for up to 6-8, 12-14, and 14-16 days, respectively. These results demonstrated that SAEW could effectively extend the shelf life of beef in comparison with that of other treatments. However, there were no significant differences (p > 0.05) between the untreated and SAEW-treated group in the content of thiobarbituric acid, suggesting that SAEW does not possess antioxidant activity. Therefore, further studies are required to increase its antioxidant activity. This study suggests that SAEW treatment is an effective and promising method to prolong the shelf life of beef by around 8 days at 4°C.

Novel approaches for chemical and microbiological shelf life extension of cereal crops

Economic losses due to post-harvest fungal spoilage and mycotoxin contamination of cereal crops is a frequently encountered issue. Typically, chemical preservatives are used to reduce the initial microbial load and the environmental conditions during storage are controlled to prevent microbial growth. However, in recent years the consumers' desire for more naturally produced foods containing less chemical preservatives has grown increasingly stronger. This article reviews the latest advances in terms of novel approaches for chemical decontamination, namely application cold atmospheric pressure plasma and electrolyzed water, and their suitability for preservation of stored cereal crops. In addition, the alternative use of bio-preservatives, such as starter cultures or purified antimicrobial compounds, to prevent the growth of spoilage organisms or remove in-field accumulated mycotoxins is evaluated. All treatments assessed here show potential for inhibition of microbial spoilage. However, each method encounters draw-backs, making industrial application difficult. Even under optimized processing conditions, it is unlikely that one single treatment can reduce the natural microbial load sufficiently. It is evident that future research needs to examine the combined application of several treatments to exploit their synergistic properties. This would enable sufficient reduction in the microbial load and ensure microbiological safety of cereal crops during long-term storage.

Risk Factors of Extended-Spectrum β-Lactamase Producing Enterobacteriaceae Occurrence in Farms in Reunion, Madagascar and Mayotte Islands, 2016-2017

In South Western Indian ocean (IO), Extended-Spectrum β-Lactamase producing Enterobacteriaceae (ESBL-E) are a main public health issue. In livestock, ESBL-E burden was unknown. The aim of this study was estimating the prevalence of ESBL-E on commercial farms in Reunion, Mayotte and Madagascar and genes involved. Secondly, risk factors of ESBL-E occurrence in broiler, beef cattle and pig farms were explored. In 2016-2017, commercial farms were sampled using boot swabs and samples stored at 4 °C before microbiological analysis for phenotypical ESBL-E and gene characterization. A dichotomous questionnaire was performed. Prevalences observed in all production types and territories were high, except for beef cattle in Reunion, which differed significantly. The most common ESBL gene was bla_CTX-M-1. Generalized linear models explaining ESBL-E occurrence varied between livestock production sectors and allowed identifying main protective (e.g., water quality control and detergent use for cleaning) and risk factors (e.g., recent antibiotic use, other farmers visiting the exploitation, pet presence). This study is the first to explore tools for antibiotic resistance management in IO farms. It provides interesting hypothesis to explore about antibiotic use in IO territories and ESBL-E transmission between pig, beef cattle and humans in Madagascar.

β-Resorcylic Acid, a Phytophenolic Compound, Reduces Campylobacter jejuni in Postharvest Poultry

Human Campylobacter infections, a leading foodborne illness globally, has been linked with the high prevalence of this bacterium on raw retail chicken products. Reduction of Campylobacter counts on poultry products would greatly reduce the risk of subsequent infections in humans. To this end, this study investigated the potential of the phytophenolic compound β-resorcylic acid (BR) to reduce Campylobacter counts on postharvest poultry (chicken skin or meat). Four trials in total, two each on thigh skin or breast meat, were conducted in which chicken skin or meat samples (2 ± 0.1 g; 10 samples per treatment) were inoculated with 50 μL (∼10⁶ CFU per sample) of a cocktail of four wild strains of C. jejuni. After 30 min of attachment, inoculated samples were dipped in a 0, 0.5, 1, or 2% BR solution for 30 s immediately followed by vigorously vortexing the samples in Butterfield's phosphate diluent and plating the supernatant for Campylobacter enumeration. In addition, the effect of BR on the color of skin and meat samples was studied. Moreover, the change in the expression of survival and virulence genes of C. jejuni exposed to BR was evaluated. Data were analyzed by the PROC MIXED procedure of SAS (P < 0.05; SAS Institute Inc., Cary, NC). All BR treatments significantly reduced Campylobacter populations on both chicken or meat samples by 1 to 3 log CFU/g compared with non-BR-treated washed controls. No significant difference in the lightness, redness, and yellowness of skin and meat samples was observed on exposure to BR wash (P > 0.05). Real-time PCR results revealed that BR treatment down-regulated expression of select genes coding for motility (motA, motB) and attachment (cadF, ciaB) in the majority of C. jejuni strains. Stress response genes (sodB, katA) were upregulated in C. jejuni S-8 (P < 0.05). Overall, our results suggest that BR could be effectively used as antimicrobial dip treatment during poultry processing for reducing Campylobacter on chicken carcasses.

Inactivation Mechanism of Escherichia coli Induced by Slightly Acidic Electrolyzed Water

Foodborne disease outbreak caused by food microbiological contamination is a serious public health problem. Slightly acidic electrolyzed water (SAEW), a new ultra-high effect and wide-spectrum disinfectant that is colourless, odourless, and harmless to humans and the environment, is directly used on food surfaces in Japan and America. However, the underlying inactivation mechanism remains unknown. In this study, biochemical and cellular changes were observed to investigate the bactericidal mechanism of SAEW against Escherichia coli (E. coli). The results indicated that SAEW with a pH of 6.40, an oxidation-reduction potential (ORP) of 910 mV, an available chlorine concentration (ACC) of 60 mg/L, and a volume ratio of 20:1, produced the most effective sterilization action. A fluorescence-based live-dead assay was further used to demonstrate the sterilized effect and the cell esterase activity damage caused by SAEW. During the observation period, within 10 min, the cell morphology changed, which was characterized by cell expansion, cell elongation and increased membrane permeability. Meanwhile, reactive oxygen substances (ROS) were released in the bacterial cells. E. coli inactivation and apoptosis induced by SAEW were observed. Our findings illustrate that the bactericidal effects of SAEW against E. coli occurred through cellular and biochemical mechanisms of cell necrosis and apoptosis.

Bactericidal activity of strong acidic hypochlorous water against Escherichia coli O157:H7 and Listeria monocytogenes in biofilms attached to stainless steel

This study aims to investigate the bactericidal activity of strong acidic hypochlorous water (SAHW) against Escherichia coli O157:H7 and L. monocytogenes in bacterial biofilms. The bactericidal activity of SAHW against both bacteria in colony biofilm increased with the elevation of the available chlorine concentration (ACC) and extension of the treatment time. The survived cell counts of E. coli O157:H7 and L. monocytogenes in the biofilms were significantly (p < 0.05) decreased compare to tap water at more than 30 mg/L of ACC in SAHW and 15 s of treatment time. E. coli O157:H7 and L. monocytogenes in the biofilms reduced to less than the detection limit by treatment of 50 mg/L of ACC in SAHW for 300 and 600 s, respectively. SAHW may be a potential disinfecting agent for removing bacterial biofilms from food processing equipment and other facilities.

Assessment of Chicken Carcass Microbiome Responses During Processing in the Presence of Commercial Antimicrobials Using a Next Generation Sequencing Approach

The purpose of this study was to 1) identify microbial compositional changes on chicken carcasses during processing, 2) determine the antimicrobial efficacy of peracetic acid (PAA) and Amplon (blend of sulfuric acid and sodium sulfate) at a poultry processing pilot plant scale, and 3) compare microbial communities between chicken carcass rinsates and recovered bacteria from media. Birds were collected from each processing step and rinsates were applied to estimate aerobic plate count (APC) and Campylobacter as well as Salmonella prevalence. Microbiome sequencing was utilized to identify microbial population changes over processing and antimicrobial treatments. Only the PAA treatment exhibited significant reduction of APC at the post chilling step while both Amplon and PAA yielded detectable Campylobacter reductions at all steps. Based on microbiome sequencing, Firmicutes were the predominant bacterial group at the phyla level with over 50% frequency in all steps while the relative abundance of Proteobacteria decreased as processing progressed. Overall microbiota between rinsate and APC plate microbial populations revealed generally similar patterns at the phyla level but they were different at the genus level. Both antimicrobials appeared to be effective on reducing problematic bacteria and microbiome can be utilized to identify optimal indicator microorganisms for enhancing product quality.

Airborne bacterial reduction by spraying slightly acidic electrolyzed water in a laying-hen house

Spraying slightly acidic electrolyzed water (SAEW) has been considered as a potential approach to reduce airborne bacteria in laying-hen houses. In this study, the effects of spraying SAEW on airborne bacterial reduction were investigated in a laying-hen house as compared with using diluted didecyl dimethyl ammonium bromide (DDAB). Averaged air temperature reduced by approximate 1 degrees C and average relative humidity increased by 3% at a stable ventilation rate (about 2.5 m3 hr(-1) per bird) in the laying-hen house 30 min after spraying (120 mL m(-2)). Compared with the control without spraying, the airborne bacterial concentration was reduced by about 0.70 and 0.37 log10 colony-forming units (CFU) m(-3) in the 4 hr after spraying 120 mL m(-2) SAEW (available chlorine concentration [ACC] of 156 mg L(-1)) and diluted DDAB (active compound concentration of 167 mg L(-1)), respectively. Compared with spraying diluted DDAB, spraying SAEW was determined to be more effective for reducing airborne bacterial in laying-hen houses. The effects of spraying SAEW and diluted DDAB on airborne bacterial reduction in the laying-hen house increased with the increasing available chlorine concentrations for SAEW (156, 206, 262 mg L(-1)) and increasing active compound concentrations for diluted DDAB (167, 333, 500 mg L(-1)), respectively. Spraying SAEW and diluted DDAB with two levels of spraying volumes (120 and 90 mL m(-2)) both showed significant differences on airborne bacterial reduction in the laying-hen house (P < 0.05).

Occurrence and population density of Campylobacter jejuni in irrigation ponds on produce farms in the Suwannee River Watershed

Campylobacter spp., especially Campylobacter jejuni, are common causal agents of gastroenteritis globally. Poultry, contaminated water, and fresh produce are considered to be the main sources for infection by this pathogen. In this study, occurrence and population density of C. jejuni from vegetable irrigation ponds in the Suwannee River watershed were investigated and the relationship to environmental factors was analyzed. Two water samples were collected from each of 10 ponds every month from January 2011 to February 2012. Campylobacter jejuni was detected by quantitative real-time PCR. Nine of the 10 ponds were positive for C. jejuni some of the time with an overall prevalence of 19.3%. The highest counts were obtained in spring 2011. Oxidation-reduction potential and total nitrogen concentration were positively correlated (P < 0.05) with mean population and occurrence of C. jejuni, while temperature and dissolved oxygen percent saturation (DO%) were negatively correlated with mean population (P < 0.05). Presence of this pathogen was related to bacterial community composition. No correlations were found between C. jejuni and fecal indicators. Increasing DO% of irrigation water and limiting nitrogen pollution in the ponds are suggested to reduce the contamination risk of C. jejuni in a major fruit and vegetable growing area.

The effect of long-term storage on the physiochemical and bactericidal properties of electrochemically activated solutions

Electrochemically activated solutions (ECAS) are generated by electrolysis of NaCl solutions, and demonstrate broad spectrum antimicrobial activity and high environmental compatibility. The biocidal efficacy of ECAS at the point of production is widely reported in the literature, as are its credentials as a "green biocide." Acidic ECAS are considered most effective as biocides at the point of production and ill suited for extended storage. Acidic ECAS samples were stored at 4 °C and 20 °C in glass and polystyrene containers for 398 days, and tested for free chlorine, pH, ORP and bactericidal activity throughout. ORP and free chlorine (mg/L) in stored ECAS declined over time, declining at the fastest rate when stored at 20 °C in polystyrene and at the slowest rate when stored at 4 °C in glass. Bactericidal efficacy was also affected by storage and ECAS failed to produce a 5 log(10) reduction on five occasions when stored at 20 °C. pH remained stable throughout the storage period. This study represents the longest storage evaluation of the physiochemical parameters and bactericidal efficacy of acidic ECAS within the published literature and reveals that acidic ECAS retain useful bactericidal activity for in excess of 12 months, widening potential applications.