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P3-74 Low Level Recovery of Escherichia coli O157:H7 and Salmonella by the BAX® System in Mechanically Collected N60 Samples of Beef Trim

Wednesday, August 6, 2014
Exhibit Hall D (Indiana Convention Center)
Julie Weller, DuPont Nutrition & Health, Wilmington, DE
Morgan Wallace, DuPont Nutrition & Health, Wilmington, DE
Steven Hoelzer, DuPont Nutrition & Health, Wilmington, DE
Stacy Stoltenberg, DuPont Nutrition & Health, Wilmington, DE
Sherri Jenkins, JBS, Greeley, CO
John Ruby, JBS, Green Bay, WI
Nisha Corrigan, DuPont Nutrition & Health, Wilmington, DE
Monica Tadler, DuPont Nutrition & Health, Wilmington, DE
Introduction: Recognizing the consumer risk of enteric pathogens in the beef industry, microbial hazard identification strategies are expanding to include the regulation of both E. coli O157:H7 and Salmonella. Standardized sampling plans such as N60 (collecting sixty 6.25g sub-samples per production lot) are being adopted to provide fast, accurate testing for both pathogens to help reduce the risk of bacterial contamination and related illness.

Purpose: This study was designed to evaluate the DuPont™ BAX® System method for detecting both E. coli O157:H7 and Salmonella in 50% lean beef trimmings collected using the IEH N60 PLUS Sampler™, a mechanical alternative collection method developed to obtain samples more efficiently than manual excision.

Methods: Beef trimmings received from a North American beef producer were artificially co-inoculated with approximately 1 CFU/150g portion each of E. coli O157:H7 and Salmonella. Samples were combined with either 600 ml of Trypitcase Soy Broth containing 2 mg/l novobiocin (TSB+n) or propriety BAX® System MP media and incubated at 42 ± 1°C for 10-22 hours. Following enrichment, samples were analyzed by real-time PCR and confirmed according to the USDA-FSIS reference culture methods.

Results:  For E. coli O157:H7 testing, PCR detected all 12 culture positive samples after enrichment in TSB+n for 12 hours and all 11 culture positive samples after enrichment in MP media for 15 hours. For Salmonella testing, PCR detected all 7 culture positive samples after enrichment in TSB+n for 12 hours and all 11 culture positive samples after enrichment in MP media for 12 hours.

Significance: This study demonstrates that beef producers can reliably use a mechanical device to collect samples and test using the BAX® System method with equivalent sensitivity to the USDA-FSIS culture methods.

Back to: Poster Session - Antimicrobials, Meat and Poultry, Microbial Food Spoilage, Seafood, Sanitation, Non-microbial Food Safety, Risk Assessment
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