IAFP 2009 Program Book and Abstract Book - AB49

beef samples where initial pathogen levels are in the 1-5 CFU range. The method is applicable to analyzing both fresh and frozen ground beef samples for the presence of E. coli O157:H7. Methods: Fresh or frozen ground beef patties (375 g) were weighed into sterile stomacher bags; one sample in each set of 10 received a low level inoculum of cold stressed nutrient starved E. coli O157:H7 (1 to 5 CFU per 3750 g) to mimic very low-level contamination. Pre-warmed Buffered Peptone Water was added and samples were pre-enriched statically at 42°C. Aliquots from each set of 10 pre-enriched, 375 g samples were pooled after pre-enrichment to create single 50 ml samples. Re-circulating immuno-magnetic separation was used to isolate E. coli O157 from the pooled samples. A 40-min, 45 cycle real-time PCR was used to detect the presence of E. coli O157:H7 in the RIMS eluate. A proportion of the recovered RIMS beads were also plated onto selective agar plates to isolate the target pathogen and confirm the real time PCR results. Results: The detection of low level E. coli O157:H7 contamination in post growth 10 pooled (3750 g) raw ground beef samples was comfortably achieved within a working day using the RIMS pooling strategy linked to real time PCR detection. Recovery of E. coli O157:H7 colonies on selective agar plates confirmed the PCR result in all cases. Significance: The RIMS 10 pooling method for E. coli O157:H7 in fresh and frozen ground beef offers high sample throughput, significant cost savings and enhanced pathogen detection. There is no loss of sensitivity, as sample pooling is carried out after pathogen growth but prior to PCR detection. Full traceability of the original sample is maintained until results are confirmed. T6-12 Use of Dual Electromagnetic Radiation Technology to Reduce Salmonella and Listeria monocytogenes Risk on Cooked and Packaged Meat Products RONG MURPHY, Brandon Beard, John Marcy, Mark Berrang, Travis Selby, Brian Krueger and Clint Billman FPTI, Inc., Fayetteville, AR, USA Introduction: Pathogenic bacteria including Salmonella and Listeria can potentially contaminate Ready-to-Eat meats. These bacteria compromise the safety of our food supply. Purpose: The objective of this research was to develop and test new low-temperature pasteurization technology for packaged or thermally sensitive foods in order to reduce surface microbial contamination without significant loss in quality. Electromagnetic radiation such as ultraviolet and infrared light has been known for more than 100 years to act as a mutagen at the cellular level. Use of a dual wavelength electromagnetic radiation system including use of infrared and ultraviolet light can achieve maximal bacterial elimination on food product without intolerable heat deposition. A combination of thermal and non-thermal pasteurization treatments were applied in a continuous conveyor system to improve food safety of vacuum packaged Ready-to-Eat food product. Methods: In this study, a continuous eletromagnetic radiation system with dual wavelength of light was used to treat cooked and vacuum-packaged sausages. A cocktail of six Salmonella (S. Montevideo, S. Senftenberg, S. Gaminara, S. Heidelberg, S. Anatum, and S. Typhimurium) or a cocktail of six Listeria monocytogenes were surface-inoculated on each sausage link to result in a combined level of 109 CFU/cm2 for Salmonella or Listeria. The sausages were vacuumpackaged (6 sausages in each 1 lb/package) and held at 4°C for 60 min prior to treatment. Each package was treated in a dual wavelength electromagnetic system with a capacity 160 lb/min at a conveyor speed up to 24 ft/min. Salmonella and Listeria were enumerated on sausages. Results: Salmonella and L. monocytogenes were both reduced by 3 logs. Significance: The results from this study are important for any food processor where risk of surface pathogen contaminations is a concern. This research offers a faster, cheaper, and less quality-disruptive alternative to traditional thermal-processing for lowering foodborne pathogen levels. T7-01 An Innovative Modeling Approach for Food Safety Risk Assessment Research for the Farm-to-Fork Continuum Mokhtari Amir, Beaulieu Stephen, LEE-ANN JAYKUS and Dennis Sherri North Carolina State University, Food, Bioprocessing, and Nutrition Sciences, Raleigh, NC, USA Introduction: Quantitative probabilistic microbial risk assessment models (QPRAM) have yet to be applied to fresh fruits and vegetables. Because fresh produce is vulnerable to contamination with pathogens at any point, a farm-to-fork modeling approach is advisable. Purpose: To develop a QPRAM to characterize the risk of foodborne disease associated with a candidate pathogencommodity pair. The model was designed specifically to facilitate evaluation of the relative efficacies of potential control strategies, serving as a “virtual laboratory” for FDA to investigate alternative contamination scenarios based upon available data and evaluate the efficacy of different mitigation strategies. Methods: The initial focus was on E. coli O157:H7 and romaine lettuce. The farm-to-fork chain was subdivided into modules of production; harvest; post-harvest unit operations; distribution; and consumption. Specific risk factors were identified for each module. Information obtained through literature review and expert elicitation was used to estimate input values for the risk factors. Inputs focused on the probability of occurrence of each risk factor, and the probability of contamination conditioned on occurrence. A novel Agent-Based Modeling (ABM) framework allowed for explicit modeling of temporal and spatial impacts of risk factors along with potential interactions among modeling agents. Results: Initial model investigations indicate that animal access to the farm and irrigation are highly significant contributors to contamination of romaine lettuce on farm. Mitigation options that restrict animal access to the farm and avoid specific, low-quality sources of irrigation water were shown to effectively reduce the number of contaminated lettuce heads. Significance: The approach is relevant to a wide variety of pathogens and food commodities. It will also be instrumental in evaluating the efficacy of food safety policies and quantifying the relative reductions in risk associated with proposed interventions. Abstract Book — 49 Technical

IAFP 2009 Program Book and Abstract Book

Table of Contents for the Digital Edition of IAFP 2009 Program Book and Abstract Book