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New methods to prevent, reduce or eliminate foodborne disease agents at all points of the food chain, from farm to fork, are needed to improve the safety of the food supply to prevent illnesses and deaths and to prevent economic losses to the food industry. <P> Objectives: <li> Develop or improve methods for control or elimination of pathogens in pre-and post harvest environments including meat, poultry, seafood, fruits and vegetables and nutmeats. <li> Develop and validate mathematical modeling to gain understanding of pathogen behavior in macro- and micro-environments. <li> Investigate factors leading to the emergence, persistence and elimination of antimicrobial resistance in food processing and animal production environments. </li> <BR><BR>Outputs:<BR> <li> Validated decontamination methods that can be used by the fruit, vegetable, seafood, meat and poultry industry to enhance the safety of their finished product <li> Outreach/extension education and training materials for regulatory personnel, producers, processors, consumers, extension agents <li> Overall enhanced food safety for consumers <BR><BR>Outcomes or projected Impacts: <li> Enhanced safety of fruit, vegetable, seafood, meat, and poultry products Increased understanding of food safety measures by regulatory personnel, producers, processors, consumers, extension agents <li> Overall enhanced food safety for consumers<BR><BR> Milestones: <BR>(2007): Pre-harvest food safety: Initiate work on antimicrobial films, high pressure processing of viruses. Modeling: Develop and validate wind tunnel to validate heat transfer models. Antimicrobial drug resistance: Tetracycline resistance genes in the environment. Total bacterial population genomic DNA extracted from fecal samples and analyzed for presence of all tetracycline resistance (Tc-R) genes. <BR>(2008): Pre-harvest food safety: Initiate efforts on sanitizers, high pressure processing of vibrios. Modeling: Collect growth data of Salmonella in chicken and beef at isothermal conditions. Develop neural network model and compare its performance to statistical models. Antimicrobial drug resistance: Environmental sample collection from antibiotic free and antibiotic receiving farms and molecular analysis. Analyze tetracycline resistant isolates for (expected) tetracycline resistance genes with PCR. <BR>(2009): Pre-harvest food safety: Investigate optimization of high pressure processing in RTE seafoods. Modeling: Collect growth data of E. coli in ground beef for different fat content at isothermal conditions. Antimicrobial drug resistance: Data analysis and manuscript preparation <BR>(2010): Pre-harvest food safety: Initiate outreach activities. Modeling: Current FSIS risk assessment model for E. coli in ground beef is based on models developed using broth. <BR>(2011): Pre-harvest food safety: continue outreach activities and publish research results. Modeling: Develop heat transfer to obtain temperature profile in shell eggs during cooling.
NON-TECHNICAL SUMMARY: The Centers for Disease Control and Prevention (CDC, 1999) reported new, more accurate estimates of foodborne illnesses that occur annually. An estimated 76 million cases of foodborne illness, 325,000 hospitalizations, and 5,000 deaths occur each year from food-borne microorganisms (Mead et al., 1999). The food safety surveillance system, FoodNet, indicates that more cases of food-borne illness occurred, but fewer deaths were caused by foodborne disease agents than previously reported. Campylobacter spp. was responsible for the most cases of foodborne illness. Salmonella (nontyphoidal) caused the most deaths; Listeria monocytogenes also causing a significant number of deaths. In summary, the report indicates that foodborne pathogens have a significant impact on human health and the food industry in the United States. In addition to human suffering, foodborne illnesses also have a substantial economic impact in the United States. The annual cost of foodborne illness in the U.S. is estimated at $5-$6 billion for loss of productivity and medical expenses (Marks and Roberts, 1993). The most costly food-borne illnesses are caused by Toxoplasma gondii, Salmonella spp., Campylobacter spp., and enterohemorrhagic Escherichia coli. New methods to prevent, reduce or eliminate foodborne disease agents at all points of the food chain, from farm to fork , are needed to improve the safety of the food supply to prevent illnesses and deaths and to prevent economic losses to the food industry.
<P>APPROACH: <BR> Objective 1. Develop or improve methods for control or elimination of pathogens in pre-and post harvest environments including meat, poultry, seafood, fruits and vegetables and nutmeats. A. Post-Harvest Food Safety: Decontamination Treatments: The response of several foodborne bacteria, viruses and protozoa to UV, ozone, and hydrogen peroxide and other decontamination treatments will be examined. Bacterial foodborne pathogens to be used for the inoculated studies will include pathogenic E. coli strains associated with produce outbreaks and Salmonella spp. strains as described above.<BR><BR> Objective 3. Investigate factors leading to the emergence, persistence and elimination of antimicrobial resistance in food processing and animal production environments Antimicrobial resistance in environmental bacteria : Environmental samples have been acquired from both non-antibiotic and antibiotic receiving farms. These samples have been maintained frozen (-70oC) and will be thawed for analysis. The sampling locations include: Lagoon (subsamples), water source (wells), manure pits, core soil samples (from areas where manure has been spread, and pasture). Feed samples (corn-soybean meal) have also been obtained for the detection of any tetracycline resistance gene contamination that would assist in maintaining resistance in the animal population. Bacterial populations in these samples will be analyzed for tetracycline resistance genes using PCR methods and two sets of primers - one specific for the V3 region of ribosomal DNA that is conserved and present in all bacteria and a second set for all tetracycline resistance genes. Isolates with tetM and tetQ tetracycline resistance genes will be evaluated for the presence of conjugative transposon specific genes with specific PCR primers. For isolates with tetM the integrase gene is in the Tn916 family of conjugative transposons (Doherty et al., 2000; Montanari et al., 2003. The area of interest for the Bacteroides spp. conjugative transposons containing isolates with tetQ is in a region spanning the rteA-rteB (Chung et al., 1999). This junction is located in the central regulatory region of this type of conjugative transposon. Using isolates positive for both tetracycline resistance genes and genes specific for regions in conjugative transposon the proximity or linkage of tetracycline resistance gene to conjugative transposon gene will be determined. Southern blots will be utilized to probe chromosomal digests of positive isolates with DNA probes specific for conjugative transposons and tetracycline resistance genes The mobility of tetracycline resistance genes will be evaluated with in vitro mating experiments using wild-type isolates of commensal bacteria and selected recipients.