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<OL> <LI> Evaluate the anti-listerial and anti-E. coli 0157:H7, and anti-Salmonella activities in model systems of selected hydrophilic or hydrophobic protein films containing nisin or pediocin and/or natural phenolics at varying pH, and citric acid/EDTA levels. <LI> Test the ability of UV light treatments of the above films and determine the effect this has on anti-bacterial activities in model systems. <LI> Evaluate film combinations found most effective in controlling/reducing pathogens in objectives 1 and 2 to control/reduce pathogens pre-inoculated onto selected fresh and fresh-cut fruits and vegetables (FFCFV). <LI> Evaluate film combinations found most effective in objectives 1 and 2 to control/reduce pathogens when films are first coated onto selected FFCFV (apples, cabbage, cantaloupe cubes, carrots, sprouts and tomatoes) and then challenged with pathogens. <LI> Using no pathogen inoculations, evaluate films with optimal anti-pathogen activities for their ability to conserve the physicochemical quality and sensory attributes of FFCFV. <LI>Deliver science-based knowledge and information generated from this study to reach the consumer and fruit and vegetable processors to enable them to implement this new technology to control foodborne pathogens on these foods.
Consumers are encouraged to consume more fresh and lightly processed fruits and vegetables. These foods have been shown to be contaminated by bacterial pathogens. This study will use natural edible protein films with and without bacteriocins and additives to help increase food safety of these foods. The purpose of this study is to investigate natural edible protein films with and without bacteriocins and additives to help increase food safety of apples, cantaloupe cubes, cabbage, carrots, sprouts and tomatoes. The purpose of this study is to determine the anti-bacterial activites of selected bacteriocins and phenolics incorporated into hydrophilic/hydrophobic edible protein films/coatings against selected foodborne pathogens on selected fresh and fresh-cut fruits and vegetables.
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Protein type (whey protein/soy protein, gluten), pH (3.0-8.0) and plasticizer concentration will be optimized to produce solutions and films with desirable physical properties. The hydrophobicity of film solutions will be determined, and different concentrations of nisin/pediocin/phenolics and/or their combinations; and/or citric acid/EDTA or UV light treatments will be evaluated for their ability to inhibit growth of Salmonella, E. coli 0157:H7, and Listeria monocytogenes. The treatment combination that gives the maximum pathogen reduction will be used to coat fresh and fresh-cut fruits (apples, cantaloupe cubes) and vegetables (cabbage, carrots, sprouts, and tomatoes). Film efficacy will be judged in two independent approaches; inoculating pre-sanitized produce with pathogens, then coating with films, or coating the pre-sanitized produce, then challenging with pathogens. Coatings showing the maximal reduction of pathogens will be used for further studies to determine their effects on quality and sensory attributes of fresh and fresh-cut fruits and vegetables. The shelf life and quality attributes including color, texture, aroma and consumer acceptance of uninoculated coated and control fresh and fresh-cut fruits and vegetables will be evaluated. Food films found to work best will be communicated to the consuming public through country extension agents.
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The effectiveness of partial replacement of glycerol with citric, lactic, malic, and tartaric acids on the antimicrobial activities of nisin (205 IU/g protein)-incorporated soy protein film against Listeria monocytogenes (L.m.), E.coli 0157:H7 (E.c.), and Salmonella gaminara (S.g.) were investigated. Malic acid (2.6%) incorporated soy protein film had the fewest survivors of L.m., E.c., and S.g. (5.5, 3.0, and 6.8) log number CFU/ml, respectively). In another study, the inhibitory effect of grape seed extract (GSE) and its combined effect with nisin with and without EDTA against L.m., E.c., and S.g. were evaluated. The GSE with EDTA or nisin with EDTA treatment showed reductions of 6.1, 0.6, 2.3 or 6.8, 0.9, 1.7 logs for L.m., E.c., and S.g., respectively. However, the EDTA alone had negligible inhibitory effect against L.m., E.c., and S.g. The combined GSE and nisin with EDTA showed reductions of 8.5, 3.8, and 3.2 logs for L.m., E.c., and S.g., respectively. Addition of EDTA enhanced antimicrobial activities of GSE and nisin against L.m., E.c., and S.g. In another study the antimicrobial activities of Ginkgo biloba leaf extract (GBE) against L.m. were determined at 4 degrees Celsius, 25 degrees Celsius, and 37 degrees Celsius. L.m. grown at 37 degrees Celsius for 24 h was inoculated (6 to 7 log CFU/mL) into BHI broth containing either GBE or GBE and EDTA (1.6mg/ml) with various GBE concentrations of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 7.5, 10.0, 15.0, or 20.0% vol/vol and stored at 4 degrees Celsius, 25 degrees Celsius, and 37 degrees Celsius. The inhibitory effect of the GBE was more pronounced at low a low temperature of 4 degrees Celsius. GBE was effective in inhibiting microbial growth. Addition of EDTA enhanced antimicrobial activity of GBE.
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Malic acid incorporated soy protein film has the potential to inhibit a wide spectrum of microbes in product application. This antimicrobial incorporated film will provide poultry, meat, fruits and vegetable processors with a powerful vehicle to minimize/prevent pathogen contamination in these products. This will benefit the consumer with safer products, and the society will benefit from reduced food-borne diseases and medical costs. The combination of GSE and nisin with EDTA can be used in a variety of food products including ready-to-eat foods to minimize pathogen contamination. Ginko biloba leaf extract (GBE) is an effective antimicrobial agent. Combination of GBE and EDTA has a great potential for use in foods.