IAFP 2009 Program Book and Abstract Book - AB110

in traditional methods and eliminates the need for transfer to M broth, incubation and subsequent pooling of M broths prior to ELfA screening. Purpose: The purpose of this AOAC-RI™ independent evaluation was to compare the new method to the FDA BAM in liquid eggs, ice cream and orange juice and to the USDA FSIS MLG 4.03 method in turkey for the detection of Salmonella species. Methods: Twenty-five replicates each of liquid eggs, ice cream, orange juice and turkey were analyzed. The target level of each strain of Salmonella used for challenging the three matrices was 1 to 10 CFU/25 g. Following incubation at 35°C for 16 to 22 h, a 0.1 ml aliquot of primary enrichment was transferred to 10 ml of SX2 broth and incubated at 41.5°C for 22 to 26 h. After incubation, samples were heated by both boiling and Heat and Go processes and a 500 µl portion was added to the sample well of the test strip. The assay was initiated and results obtained within 45 min. Replicates were streaked onto chromogenic SM2 agar and reference method selective media. Final confirmations were achieved by VITEK® AOAC OMA Method 991.13. The reference methods were performed as per the FDA BAM and USDA-MLG. Results: Of 100 samples tested, the new method produced 35 confirmed positive results, compared to 34 for the reference methods. There was no significant difference between the new method and the reference methods for all four foods, as determined by Chi-square analysis at the 95% probability level. Significance: This new method demonstrates reliability as an alternative screening method for the rapid detection of Salmonella in a variety of foods. P2-18 A Comparative Evaluation of the VIDAS ® Easy Salmonella Assay for the Detection of Salmonella in Food and Poultry Rinse ERIN S. CROWLEY, Patrick Bird, Marianne Torontali, Katherine Goetz, James Agin, David Goins, Ray Turnley and Ronald Johnson Q Laboratories, Inc., Microbiology R&D, Cincinnati, OH, USA Introduction: Current Salmonella methods are often time consuming and can take up to 5 days to obtain a negative result. This new screening method detects Salmonella spp. in food and environmentals in less than 40 h. The alternative method utilizes a simple 2-step enrichment procedure for use with the enzyme linked immuno-fluorescent assay (ELFA). In the new enrichment protocol, a single selective proprietary broth (SX2) replaces the two broths in traditional methods and eliminates the need for transfer to M broth, incubation and subsequent pooling of M broths prior to ELfA screening. Purpose: The purpose of this evaluation was to compare the VIDAS® Easy Salmonella method to the USDA FSIS MLG 4.04 and an immunoassay method utilizing a lateral flow test strip for the detection of Salmonella spp. in poultry. Methods: Twenty-five replicates each of cooked turkey, raw ground turkey and poultry rinse were analyzed. The target levels of each strain of Salmonella used for challenging the three matrices were 0.2 to 2 CFU/g. Replicates of cooked turkey and raw ground turkey were enriched in BPW and poultry rinse in 2XBPW and incubated at 35°C for 16 to 22 h. A 0.1 ml aliquot of primary enrichment was transferred to 10 ml of SX2 broth and incubated at 41.5°C for 22 to 26 h. A 500 µl portion was added to the sample well of the test strip and heated by Heat and Go at 131°C for 15 min, cooled and loaded into the system. The assay was initiated and results obtained within 45 min. Replicates were streaked onto chromogenic SM2 agar and reference method selective media. The lateral flow test strip method was performed as per the instructions provided in the package insert and the reference method as per USDA-MLG. Final confirmations were performed by VITEK® AOAC OMA Method 991.13. Results: Of 75 samples tested, the new method produced 40 confirmed positive results, compared with 41 for the USDA reference method and 32 for the lateral flow test strip method. There was no significant difference between the new method and the reference method for all matrices tested, including cooked turkey, raw ground turkey and poultry rinse, as determined by Chi-square analysis. There was a significant difference between the lateral flow method and the reference method for poultry rinse. Significance: This new method is an accurate, reliable detection assay and can be a favorable alternative to traditional reference methods of detecting Salmonella species in food, with presumptive results available on the second day after sample set up. P2-19 Compositing Produce Rinse Samples for Increased Throughput for Real-time PCR Detection and Recovery of Salmonella and Escherichia coli O157:H7 in Artificially Contaminated Produce Stephen D. Weagant, Ken J. Yoshitomi, Karen C. Jinneman, Chorng-Ming Cheng, Ruben Zapata, Paul Browning and WILLIS M. FEDIO New Mexico State University, Food Safety Laboratory, Las Cruces, NM, USA Introduction: Salmonella spp. and Escherichia coli O157:H7 have been responsible for a number of foodborne disease outbreaks associated with fresh produce. Detection and isolation of these pathogens is time consuming and labor intensive. High throughput for sample analysis of multiple pathogens could be improved with the use of a universal rinse and compositing protocol. Purpose: To assess the effect of compositing rinsates prepared from leafy vegetable samples on the sensitivity of detection and recovery of Salmonella Typhimurium and Escherichia coli O157:H7. Spinach, Romaine lettuce, green onions, basil and cilantro were used as food matrices. Methods: For each type of produce, one of five samples (500 g) was inoculated with Salmonella Typhimurium and E. coli O157:H7. Three inoculation levels were evaluated: approximately 0.1 CFU/g, 1 CFU/g and 10 CFU/g produce. Samples were rinsed with Butterfield’s Phosphate Buffer and rinsate portions were tested. For compositing, each contaminated rinsate was combined with four uncontaminated rinsates. Individual and composited sample rinsates Poster 110 — Abstract Book

IAFP 2009 Program Book and Abstract Book

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