In ovo probiotic supplementation supports hatchability and improves hatchling quality in broilers.

In modern broilers, the period of embryonic development constitutes a greater proportion of a broiler's productive life. Hence, optimum embryonic development can exert a significant influence not only on chick hatchability and hatchling quality but also on overall broiler growth and performance. Further healthy and active hatchlings are correlated with improved posthatch performance. In this regard, probiotics are good candidates to mediate early-life programming. Therefore, we evaluated the effect of In ovo probiotic spray application on broiler hatchability and hatchling quality. The experiment was set out as a completely randomized study with 2 independent trials. In each trial, 540 eggs (Ross 308) were either sprayed with phosphate buffered saline (PBS; control) or probiotics [∼9 log CFU/egg of Lactobacillus rhamnosus NRRL B-442(LR) or Lactobacillus paracasei DUP 13076 (LP)] during incubation. On day 18, eggs were transferred to the hatcher and set up for hatching. Starting on day 19, eggs were observed for hatching to determine the spread of hatch and hatchability. Hatched chicks were then assessed for quality using the Tona and Pasgar score and morphometric measurements including hatchling weight, yolk-free-body-mass and hatchling length were measured. Further, chicks were reared in floor pens for 3 wk to assess posthatch growth. Overall, In ovo probiotic supplementation improved hatchability and hatchling quality. Specifically, the spray application of LP improved hatchability by ∼ 5% without affecting the spread of hatch. Further, both LR and LP significantly improved Pasgar and Tona score, indicating an improvement in hatchling quality. Also, LP and LR significantly improved hatchling weight, yolk-free-body-mass, and posthatch growth in chicks. LR significantly improved hatchling weight and hatchling length (P < 0.05). Moreover, this increase in posthatch growth was positively correlated with hatchling weight in the probiotic groups. Overall, our study demonstrates that In ovo probiotic application exerts a positive effect on hatchability, hatchling quality, and subsequent posthatch growth.

Cultivating Food Safety Together: Insights About the Future of Produce Safety in the U.S. Controlled Environment Agriculture Sector.

Controlled environment agriculture (CEA) is a rapidly growing sector that presents unique challenges and opportunities in ensuring food safety. This manuscript highlights critical gaps and needs to promote food safety in CEA systems as identified by stakeholders (n=47) at the Strategizing to Advance Future Extension andResearch (S.A.F.E.R.) CEA conference held in April 2023 at The Ohio State University's Ohio CEA Research Center. Feedback collected at the conference was analyzed using an emergent thematic analysis approach to determine key areas of focus. Research-based guidance is specific to the type of commodity, production system type, and size. Themes include the need for improved supply chain control, cleaning, and sanitization practices, pathogen preventive controls and mitigation methods and training and education. Discussions surrounding supply chain control underscored the significance of the need for approaches to mitigate foodborne pathogen contamination. Effective cleaning and sanitization practices are vital to maintaining a safe production environment, with considerations such as establishing standard operating procedures, accounting for hygienic equipment design, and managing the microbial communities within the system. Data analysis further highlights the need for risk assessments, validated pathogen detection methods, and evidence-based guidance in microbial reduction. In addition, training and education were identified as crucial in promoting a culture of food safety within CEA. The development of partnerships between industry, regulatory, and research institutions are needed to advance data-driven guidance and practices across the diverse range of CEA operations and deemed essential for addressing challenges and advancing food safety practices in CEA. Considering these factors, the CEA industry can enhance food safety practices, foster consumer trust, and support its long-term sustainability.

Research Note: In ovo and in-feed probiotic supplementation improves layer embryo and pullet growth.

Probiotics are widely used as feed supplements in the poultry industry to promote growth and performance in chickens. Specifically, this supplementation starts around the time of lay and continues through the production cycle in laying hens. However, the embryonic period is critical to the growth and development of metabolically active organs thereby influencing subsequent health and productivity in adult birds. Therefore, the present study investigated the potential use of probiotics to promote embryonic growth in layers. Further, a pilot grow-out study was conducted to evaluate the effect of in ovo and in-feed probiotic application on pullet growth. For the study, fertile White Leghorn eggs were sprayed with phosphate buffered saline (control, CON) or probiotic cocktail (in ovo only, IO; Lactobacillus paracasei DUP 13076 and L. rhamnosus NRRL B 442) prior to and during incubation. The embryos were sacrificed on d 7, 10, 14, and 18 of incubation for embryo morphometry. On d 18, remaining eggs were set in the hatcher to assess hatchability and hatchling morphometry. For the pullet trial, hatchlings were raised on feed with or without probiotics until wk 5. Pullets were sacrificed weekly, and morphometric parameters were recorded. Results of our study demonstrate that in ovo probiotic application significantly improved relative embryo weight, crown-rump length, hatchability, and hatchling weight when compared to the control (P < 0.05). Further, this enhanced embryonic development was associated with a concomitant increase in posthatch growth. Specifically, pullets raised from probiotic-sprayed eggs had significantly improved crown-rump length, tibial length, tibial bone weight, and body weight when compared to the control (P < 0.05). Moreover, among the different treatment schemes employed in this study [CON (no probiotics), in-feed only (IF), IO only, and in ovo and in-feed probiotic supplementation (IOIF)], sustained probiotic supplementation (IOIF) was found to be the most effective in promoting growth. Therefore, in ovo and in-feed probiotic supplementation could be employed to promote embryo and pullet growth to support subsequent performance in layers.

Cell-surface anchoring of Listeria adhesion protein on L. monocytogenes is fastened by internalin B for pathogenesis.

Listeria adhesion protein (LAP) is a secreted acetaldehyde alcohol dehydrogenase (AdhE) that anchors to an unknown molecule on the Listeria monocytogenes (Lm) surface, which is critical for its intestinal epithelium crossing. In the present work, immunoprecipitation and mass spectrometry identify internalin B (InlB) as the primary ligand of LAP (KD ∼ 42 nM). InlB-deleted and naturally InlB-deficient Lm strains show reduced LAP-InlB interaction and LAP-mediated pathology in the murine intestine and brain invasion. InlB-overexpressing non-pathogenic Listeria innocua also displays LAP-InlB interplay. In silico predictions reveal that a pocket region in the C-terminal domain of tetrameric LAP is the binding site for InlB. LAP variants containing mutations in negatively charged (E523S, E621S) amino acids in the C terminus confirm altered binding conformations and weaker affinity for InlB. InlB transforms the housekeeping enzyme, AdhE (LAP), into a moonlighting pathogenic factor by fastening on the cell surface.

In ovo probiotic supplementation promotes muscle growth and development in broiler embryos.

In chickens, muscle development during embryonic growth is predominantly by myofiber hyperplasia. Following hatch, muscle growth primarily occurs via hypertrophy of the existing myofibers. Since myofiber number is set at hatch, production of more muscle fibers during embryonic growth would provide a greater myofiber number at hatch and potential for posthatch muscle growth by hypertrophy. Therefore, to improve performance in broilers, this study investigated the effect of in ovo spray application of probiotics on overall morphometry and muscle development in broiler embryos. For the study, fertile Ross 308 eggs were sprayed with different probiotics; Lactobacillus paracasei DUP 13076 (LP) and L. rhamnosus NRRL B 442 (LR) prior to and during incubation. The embryos were sacrificed on d 7, 10, 14, and 18 for embryo morphometry and pectoralis major muscle (PMM) sampling. Muscle sections were stained and imaged to quantify muscle fiber density (MFD), myofiber cross-sectional area (CSA), and nuclei density. Additionally, gene expression assays were performed to elucidate the effect of probiotics on myogenic genes. In ovo probiotic supplementation was found to significantly improve embryo weight, breast weight, and leg weight (P < 0.05). Further, histological analysis of PMM revealed a significant increase in MFD and nuclei number in the probiotic-treated embryos when compared to the control (P < 0.05). In 18-day-old broiler embryos, myofibers in the treatment group had a significantly smaller CSA (LP: 95.27 ± 3.28 µm2, LR: 178.84 ± 15.1 µm2) when compared to the control (211.41 ± 15.67 µm2). This decrease in CSA was found to be associated with a concomitant increase in MFD (fibers/mm2) in the LP (13,647 ± 482.15) and LR (13,957 ± 463.13) group when compared to the control (7,680 ± 406.78). Additionally, this increase in myofibrillar hyperplasia in the treatment groups was associated with upregulation in the expression of key genes regulating muscle growth including MYF5, MYOD, MYOG, and IGF-1. In summary, in ovo spray application of probiotics promoted overall embryo growth and muscle development in broilers.

Listeria monocytogenes Survival on Peaches and Nectarines under Conditions Simulating Commercial Stone-Fruit Packinghouse Operations.

Recent recalls of stone fruit due to potential Listeria contamination and associated foodborne outbreaks highlight the risk for pathogen transmission through stone-fruit consumption. Particularly, surface contamination of fruits increases the risk for cross-contamination of produce during processing and storage. This highlights the need for quality control in stone fruits intended for consumption. To develop effective food safety practices, it is essential to determine the critical factors during stone-fruit processing that influence Listeria survival. Therefore, this study evaluated the ability of Listeria to survive on peaches and nectarines under simulated stone-fruit loading and staging, waxing and fungicide application and storage conditions. The results of our study indicate that current stone-fruit handling conditions do not favor Listeria growth. However, once fruit is contaminated, Listeria can survive on the fruit surface in significant numbers under current processing conditions. Therefore, there is a need to develop and implement preventive controls at the stone-fruit packinghouse to prevent Listeria contamination and deter pathogen persistence.

Receptor-targeted engineered probiotics mitigate lethal Listeria infection.

Probiotic bacteria reduce the intestinal colonization of pathogens. Yet, their use in preventing fatal infection caused by foodborne Listeria monocytogenes (Lm), is inconsistent. Here, we bioengineered Lactobacillus probiotics (BLP) to express the Listeria adhesion protein (LAP) from a non-pathogenic Listeria (L. innocua) and a pathogenic Listeria (Lm) on the surface of Lactobacillus casei. The BLP strains colonize the intestine, reduce Lm mucosal colonization and systemic dissemination, and protect mice from lethal infection. The BLP competitively excludes Lm by occupying the surface presented LAP receptor, heat shock protein 60 and ameliorates the Lm-induced intestinal barrier dysfunction by blocking the nuclear factor-κB and myosin light chain kinase-mediated redistribution of the major epithelial junctional proteins. Additionally, the BLP increases intestinal immunomodulatory functions by recruiting FOXP3+T cells, CD11c+ dendritic cells and natural killer cells. Engineering a probiotic strain with an adhesion protein from a non-pathogenic bacterium provides a new paradigm to exclude pathogens and amplify their inherent health benefits.

Attachment of Salmonella enterica on Mangoes and Survival Under Conditions Simulating Commercial Mango Packing House and Importer Facility.

Consumption of raw mangoes has led to multiple Salmonella-associated foodborne outbreaks in the United States. Although several studies have investigated the epiphytic fitness of Salmonella on fresh produce, there is sparse information available on the survival of Salmonella on mangoes under commercial handling and storage conditions. Hence, the objective of the study was to evaluate the survival of Salmonella on mangoes under ambient conditions simulating the mango packing house and importer facility. Further, the ability of the pathogen to adhere and attach on to the mango fructoplane was also investigated. For the attachment assays, mango skin sections were inoculated with fifty microliters of S. Newport suspension (6.5 log CFU/skin section) and minimum time required for adhesion and attachment were recorded. With the survival assays, unwaxed mangoes were spot inoculated with the Salmonella cocktail to establish approximately 4 and 6.5 log CFU/mango. The fruits were then subjected to different storage regimens simulating fruit unloading, waxing, and storage at the packing house and ripening and storage at the importer facility. Results of our study reveal that Salmonella was able to adhere on to the fructoplane immediately after contact. Further, formation of attachment structures was seen as early as 2 min following inoculation. With the survival assays, irrespective of the inoculum levels, no significant increase or decrease in pathogen population was observed when fruit were stored either at ambient (29-32°C and RH 85-95%, for 48 h), ripening (20-22°C and RH 90-95% for 9 days) or refrigerated storage (10-15°C and 85-95% for 24-48 h) conditions. Therefore, once contaminated, mangoes could serve as potential vehicles in the transmission of Salmonella along the post-harvest environment. Hence development and adoption of effective food safety measures are warranted to promote the microbiological safety of mangoes.

Inhibition and Inactivation of Uropathogenic Escherichia coli Biofilms on Urinary Catheters by Sodium Selenite.

Urinary tract infections (UTI) are the most common hospital-acquired infections in humans and are caused primarily by uropathogenic Escherichia coli (UPEC). Indwelling urinary catheters become encrusted with UPEC biofilms that are resistant to common antibiotics, resulting in chronic infections. Therefore, it is important to control UPEC biofilms on catheters to reduce the risk for UTIs. This study investigated the efficacy of selenium for inhibiting and inactivating UPEC biofilms on urinary catheters. Urinary catheters were inoculated with UPEC and treated with 0 and 35 mM selenium at 37 °C for 5 days for the biofilm inhibition assay. In addition, catheters with preformed UPEC biofilms were treated with 0, 45, 60, and 85 mM selenium and incubated at 37 °C. Biofilm-associated UPEC counts on catheters were enumerated on days 0, 1, 3, and 5 of incubation. Additionally, the effect of selenium on exopolysacchride (EPS) production and expression of UPEC biofilm-associated genes was evaluated. Selenium at 35 mM concentration was effective in preventing UPEC biofilm formation on catheters compared to controls (p < 0.05). Further, this inhibitory effect was associated with a reduction in EPS production and UPEC gene expression. Moreover, at higher concentrations, selenium was effective in inactivating preformed UPEC biofilms on catheters as early as day 3 of incubation. Results suggest that selenium could be potentially used in the control of UPEC biofilms on urinary catheters.

Attachment and Survival of Escherichia coli O157:H7 on In-Shell Hazelnuts.

The multistate Escherichia coli (E. coli) O157:H7 outbreak associated with in-shell hazelnuts highlights the pathogen's ability to involve non-traditional vehicles in foodborne infections. Furthermore, it underscores significant gaps in our knowledge of pathogen survivability and persistence on nuts. Therefore, this study investigated the ability of E. coli O157:H7 to attach and survive on in-shell hazelnuts. In-shell hazelnuts were inoculated with a four-strain mixture of E. coli O157:H7 at 7.6 log colony forming units (CFU)/nut by wet or dry inoculation, stored at ambient conditions (24 ± 1 °C; 40% ± 3% relative humidity (RH) and sampled for twelve months. For the attachment assay, in-shell hazelnuts were inoculated and the adherent population was enumerated at 30 s-1 h following inoculation. Irrespective of the inoculation method, ~5 log CFU of adherent E. coli O157:H7 was recovered from the hazelnuts as early as 30 s after inoculation. Conversely, pathogen survival was significantly reduced under dry inoculation with samples being enrichment negative after five months of storage (p < 0.05). On the other hand, wet inoculation led to a significantly longer persistence of the pathogen with ~3 log CFU being recovered from the in-shell nuts at 12 months of storage (p < 0.05). These results indicate that E. coli O157:H7 can survive in significant numbers on in-shell hazelnuts when stored under ambient conditions.

Draft Genome Sequence of Lactobacillus rhamnosus NRRL B-442, a Potential Probiotic Strain.

Lactic acid bacteria are known to exhibit probiotic properties through various mechanisms, including competitive exclusion, pathogen inhibition, production of antimicrobial substances, and maintenance of eubiosis. Here, we present the draft genome sequence of a novel probiotic strain, Lactobacillus rhamnosus strain NRRL B-442, which exhibits potent antivirulence activity against Salmonella enterica.

Draft Genome Sequence of Lactobacillus paracasei DUP 13076, Which Exhibits Potent Antipathogenic Effects against Salmonella enterica Serovars Enteritidis, Typhimurium, and Heidelberg.

Lactobacillus paracasei DUP 13076 demonstrates antagonistic effects against the foodborne pathogens Salmonella enterica serovars Enteritidis, Typhimurium, and Heidelberg in coculture and in vitro experiments. Here, we report the draft genome sequence of Lactobacillus paracasei DUP 13076, which has a circular chromosome of 3,048,314 bp and a G+C content of 46.3%.

Controlling the Graphene-Bio Interface: Dispersions in Animal Sera for Enhanced Stability and Reduced Toxicity.

Liquid phase exfoliation of graphite in six different animal sera and evaluation of its toxicity are reported here. Previously, we reported the exfoliation of graphene using proteins, and here we extend this approach to complex animal fluids. A kitchen blender with a high-turbulence flow gave high quality and maximum exfoliation efficiency in all sera tested, when compared to the values found with shear and ultrasonication methods. Raman spectra and electron microscopy confirmed the formation of three- or four-layer, submicrometer size graphene, independent of the serum used. Graphene prepared in serum was directly transferred to cell culture media without post-treatments. Contrary to many reports, a nanotoxicity study of this graphene fully dispersed to human embryonic kidney cells, human lung cancer cells, and nematodes (Caenorhabditis elegans) showed no acute toxicity for up to 7 days at various doses (50-500 µg/mL), but prolonged exposure at higher doses (300-500 µg/mL, 10-15 days) showed cytotoxicity to cells (∼95% death) and reproductive toxicity to C. elegans (5-10% reduction in brood size). The origin of toxicity was found to be due to the highly fragmented smaller graphene sheets (<200 nm), while the larger sheets were nontoxic (50-300 µg/mL dose). In contrast, graphene produced with sodium cholate as the mediator has been found to be cytotoxic to these cells at these dosages. We demonstrated the toxicity of liquid phase exfoliated graphene is attributed to highly fragmented fractions or nonbiocompatible exfoliating agents. Thus, low-toxicity graphene/serum suspensions are produced by a facile method in biological media, and this approach may accelerate the much-anticipated development of graphene for biological applications.

Lactobacillus bulgaricus, Lactobacillus rhamnosus and Lactobacillus paracasei Attenuate Salmonella Enteritidis, Salmonella Heidelberg and Salmonella Typhimurium Colonization and Virulence Gene Expression In Vitro.

Salmonella Enteritidis (SE), Salmonella Typhimurium (ST), and Salmonella Heidelberg (SH) have been responsible for numerous outbreaks associated with the consumption of poultry meat and eggs. Salmonella colonization in chicken is characterized by initial attachment to the cecal epithelial cells (CEC) followed by dissemination to the liver, spleen, and oviduct. Since cecal colonization is critical to Salmonella transmission along the food chain continuum, reducing this intestinal association could potentially decrease poultry meat and egg contamination. Hence, this study investigated the efficacy of Lactobacillus delbreuckii sub species bulgaricus (NRRL B548; LD), Lactobacillus paracasei (DUP-13076; LP), and Lactobacillus rhamnosus (NRRL B442; LR) in reducing SE, ST, and SH colonization in CEC and survival in chicken macrophages. Additionally, their effect on expression of Salmonella virulence genes essential for cecal colonization and survival in macrophages was evaluated. All three probiotics significantly reduced Salmonella adhesion and invasion in CEC and survival in chicken macrophages (p < 0.05). Further, the probiotic treatment led to a significant reduction in Salmonella virulence gene expression (p < 0.05). Results of the study indicate that LD, LP, and LR could potentially be used to control SE, ST, and SH colonization in chicken. However, these observations warrant further in vivo validation.

Inactivation of Acinetobacter baumannii Biofilms on Polystyrene, Stainless Steel, and Urinary Catheters by Octenidine Dihydrochloride.

Acinetobacter baumannii is a major nosocomial pathogen causing human infections with significant mortality rates. In most cases, infections are acquired through exposure to A. baumannii biofilms that persist on contaminated hospital equipment and surfaces. Thus, it is imperative to develop effective measures for controlling A. baumannii biofilms in nosocomial settings. This study investigated the efficacy of octenidine dihydrochloride (OH), a new generation disinfectant for reducing A. baumannii biofilms on polystyrene, stainless steel and catheters. OH at 0.3% (5 mM), 0.6% (10 mM), and 0.9% (15 mM) was effective in significantly inactivating A. baumannii biofilms on all tested surfaces (P < 0.05). Furthermore, OH was equally effective in inactivating biofilms of multidrug resistant and drug susceptible A. baumannii isolates. In addition, confocal imaging revealed the predominance of dead cells in the OH-treated samples in comparison to the control. Further, scanning electron microscopy of biofilms formed on catheters revealed that OH treatment significantly reduced A. baumannii biofilm populations in corroboration with our antibiofilm assay. These data underscore the efficacy of OH in inactivating A. baumannii biofilms, thereby suggesting its potential use as a disinfectant or a catheter lock solution to control A. baumannii infections.

Anticarcinogenic properties of medium chain fatty acids on human colorectal, skin and breast cancer cells in vitro.

Colorectal cancer, breast cancer and skin cancer are commonly-reported cancer types in the U.S. Although radiation and chemotherapy are routinely used to treat cancer, they produce side effects in patients. Additionally, resistance to chemotherapeutic drugs has been noticed in cancers. Thus, there is a need for effective and safe bioprophylactics and biotherapeutics in cancer therapy. The medicinal value of goat milk has been recognized for centuries and is primarily attributed to three fatty acids, namely capric, caprylic and caproic acids. This research investigates the anticancer property of these fatty acids on human colorectal, skin and mammary gland cancer cells. The cancer cells were treated with various concentrations of fatty acids for 48 h, and cell viability was monitored by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. Additionally, real-time quantitative PCR (RT-qPCR) was performed to elucidate the potential anti-cancer mechanisms of the three fatty acids under investigation. Capric, caprylic and caproic acids reduced cancer cell viability by 70% to 90% (p < 0.05) compared to controls. RT-qPCR data indicated that these natural molecules produced anticancer effects by down-regulating cell cycle regulatory genes and up-regulating genes involved in apoptosis. Future research will validate the anticancer effect of these fatty acids in an appropriate in vivo model.

Antibiofilm Effect of Octenidine Hydrochloride on Staphylococcus aureus, MRSA and VRSA.

Millions of indwelling devices are implanted in patients every year, and staphylococci (S. aureus, MRSA and vancomycin-resistant S. aureus (VRSA)) are responsible for a majority of infections associated with these devices, thereby leading to treatment failures. Once established, staphylococcal biofilms become resistant to antimicrobial treatment and host response, thereby serving as the etiological agent for recurrent infections. This study investigated the efficacy of octenidine hydrochloride (OH) for inhibiting biofilm synthesis and inactivating fully-formed staphylococcal biofilm on different matrices in the presence and absence of serum protein. Polystyrene plates and stainless steel coupons inoculated with S. aureus, MRSA or VRSA were treated with OH (zero, 0.5, one, 2 mM) at 37 °C for the prevention of biofilm formation. Additionally, the antibiofilm effect of OH (zero, 2.5, five, 10 mM) on fully-formed staphylococcal biofilms on polystyrene plates, stainless steel coupons and urinary catheters was investigated. OH was effective in rapidly inactivating planktonic and biofilm cells of S. aureus, MRSA and VRSA on polystyrene plates, stainless steel coupons and urinary catheters in the presence and absence of serum proteins. The use of two and 10 mM OH completely inactivated S. aureus planktonic cells and biofilm (>6.0 log reduction) on all matrices tested immediately upon exposure. Further, confocal imaging revealed the presence of dead cells and loss in biofilm architecture in the OH-treated samples when compared to intact live biofilm in the control. Results suggest that OH could be applied as an effective antimicrobial to control biofilms of S. aureus, MRSA and VRSA on appropriate hospital surfaces and indwelling devices.

Sub-inhibitory concentrations of trans-cinnamaldehyde attenuate virulence in Cronobacter sakazakii in vitro.

Cronobacter sakazakii is a foodborne pathogen, which causes a life-threatening form of meningitis, necrotizing colitis and meningoencephalitis in neonates and children. Epidemiological studies implicate dried infant formula as the principal source of C. sakazakii. In this study, we investigated the efficacy of sub-inhibitory concentrations (SIC) of trans-cinnamaldehyde (TC), an ingredient in cinnamon, for reducing C. sakazakii virulence in vitro using cell culture, microscopy and gene expression assays. TC significantly (p ≤ 0.05) suppressed C. sakazakii adhesion to and invasion of human and rat intestinal epithelial cells, and human brain microvascular endothelial cells. In addition, TC inhibited C. sakazakii survival and replication in human macrophages. We also observed that TC reduced the ability of C. sakazakii to cause cell death in rat intestinal cells, by inhibiting nitric oxide production. Results from gene expression studies revealed that TC significantly downregulated the virulence genes critical for motility, host tissue adhesion and invasion, macrophage survival, and LPS (Lipopolysaccharide) synthesis in C. sakazakii. The efficacy of TC in attenuating these major virulence factors in C. sakazakii underscores its potential use in the prevention and/or control of infection caused by this pathogen.

Efficacy of plant-derived antimicrobials as antimicrobial wash treatments for reducing enterohemorrhagic Escherichia coli O157:H7 on apples.

This study investigated the efficacy of 3 GRAS-status, plant-derived antimicrobials (PDAs), trans-cinnamaldehyde (TC), carvacrol (CR), and ß-resorcylic acid (BR) applied as an antimicrobial wash for killing Escherichia coli O157:H7 on apples. "Red delicious" apples inoculated with a 5 strain mixture of E. coli O157:H7 were subjected to washing in sterile deionized water containing 0% PDA (control), 0.15% TC, 0.35% TC, 0.15% CR, 0.30% CR, 0.5% BR, or 1% BR for 1, 3, and 5 min at 23 °C in the presence and absence of 1% soil, and surviving pathogen populations on apples were enumerated at each specified time. All PDAs were more effective in reducing E. coli O157:H7 compared to the water wash treatment (P < 0.05) and reduced the pathogen by 4- to 5-log CFU/apple in 5 min. Chlorine (1%) was the most effective treatment reducing the pathogen on apples to undetectable levels in 1 min (P < 0.05). Moreover, the antimicrobial effect of CR and BR was not affected by the presence of soil, whereas the efficacy of TC and BR was decreased in the presence of soil. Further, no bacteria were detected in the wash solution containing CR and BR; however, E. coli O157:H7 was recovered in the control wash water and treatment solutions containing TC and chlorine, in the presence of 1% soil (P < 0.05). Results suggest that the aforementioned PDAs, especially CR and BR could be used effectively to kill E. coli O157:H7 on apples when used as a wash treatment. Studies on the sensory and quality characteristics of apples treated with PDAs are needed before recommending their usage.

Rapid sample processing for detection of food-borne pathogens via cross-flow microfiltration.

This paper reports an approach to enable rapid concentration and recovery of bacterial cells from aqueous chicken homogenates as a preanalytical step of detection. This approach includes biochemical pretreatment and prefiltration of food samples and development of an automated cell concentration instrument based on cross-flow microfiltration. A polysulfone hollow-fiber membrane module having a nominal pore size of 0.2 µm constitutes the core of the cell concentration instrument. The aqueous chicken homogenate samples were circulated within the cross-flow system achieving 500- to 1,000-fold concentration of inoculated Salmonella enterica serovar Enteritidis and naturally occurring microbiota with 70% recovery of viable cells as determined by plate counting and quantitative PCR (qPCR) within 35 to 45 min. These steps enabled 10 CFU/ml microorganisms in chicken homogenates or 10(2) CFU/g chicken to be quantified. Cleaning and sterilizing the instrument and membrane module by stepwise hydraulic and chemical cleaning (sodium hydroxide and ethanol) enabled reuse of the membrane 15 times before replacement. This approach begins to address the critical need for the food industry for detecting food pathogens within 6 h or less.