4. AOACRIMicroMethods-2018Awards

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868  W allace et al . : J ournal of AOAC I nternational V ol . 97, N o . 3, 2014

FOOD BIOLOGICAL CONTAMINANTS

Detection of Salmonella species in a Variety of Foods by the DuPont ™ BAX ® System Real-Time PCRAssay for Salmonella : First Action 2013.02 F. M organ W allace , B ridget A ndaloro , D awn F allon , N isha C orrigan , S tephen V arkey , D aniel D e M arco , A ndrew F arnum , M onica T adler , S teven H oelzer , J ulie W eller , E ugene D avis , J effrey R ohrbeck , and G eorge T ice DuPont Nutrition & Health, ESL Building 400, Route 141 and Henry Clay Rd, Wilmington, DE 19880 P atrick B ird , E rin C rowley , J onathan F lannery , K iel F isher , T ravis H uffman , M egan B oyle , M. J oseph B enzinger , J r , P aige B edinghaus , K atie G oetz , W illiam J udd , J im A gin , and D avid G oins Q Laboratories, Inc., 1400 Harrison Ave, Cincinnati, OH 45214 Collaborators: C. Churchill; D. Clark, Jr; B. Dieckelman; T. Donohue; H. Elgaali; W. Fedio; E. Galbraith; L. Hahn; D. Kondratko; B. Kupski; K. McCallum; G. McWhorter; J. Meyer; J. Putrow; R. Radcliff; D. Rodgers; S. Scott; D. Swift; L. Thompson

S almonella is a leading cause of foodborne illness. The low infectious dose of the bacterium makes it critical to detect even low concentrations of the Salmonella in foods. Additionally, the presence of high concentrations of closely related nonpathogenic bacteria create the need for highly accurate methodologies. Traditionally, laboratories concerned with detection of Salmonella screened food samples with culture methods, such as those provided by the U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) and the U.S. Food and Drug Administration (FDA), which require several days to detect and confirm Salmonella . Rapid methods of screening for Salmonella have been developed, but these generally require 2 days of enrichment. By contrast, the DuPont™ BAX ® System detects the pathogen less than 90 min after enrichment, and the DNA-based results are both reliable and reproducible, leading to quicker release of cleared product. The BAX System Real-Time PCR Assay for Salmonella was certified by the AOAC Research Institute in August 2012 and designated Performance Tested Method SM (PTM) No. 081201. No significant differences were reported for detection of Salmonella in the matrixes tested when comparing the BAX System method results to the standard reference culture procedures described in the USDA-FSIS Microbiology Laboratory Guidebook (MLG; 1), FDA Bacteriological Analytical Manual (BAM; 2), and Health Canada Compendium of Analytical Methods (HC CAM; 3). The matrixes validated in the PTM study included raw ground beef (85% lean, 25 and 375 g), chicken carcass rinse, cream cheese (34% fat), fresh bagged lettuce, dry pet food, and stainless steel. Inclusivity testing demonstrated that the BAX System method was reactive with 317 Salmonella isolates, representing over 100 different serotypes. The test method did not detect 37 different non- Salmonella strains tested (Appendix 1; see appendixes on J. AOAC Int. website, http://aoac.publisher.ingentaconnect.com/content/aoac/jaoac). After the PTM approval was achieved, a procedure change was applied to this validation to incorporate an eight-cycle increase in processing time in the BAX System Q7 instrument (Appendix 2). Following the completion of the PTMstudy, a precollaborative study was conducted on an additional 18 matrixes, including

Received December 13, 2013. The method was approved by the Expert Review Panel for Food Biological Contaminants as First Action. The Expert Review Panel for Food Biological Contaminants invites method users to provide feedback on the First Action methods. Feedback from method users will help verify that the methods are fit for purpose and are critical to gaining global recognition and acceptance of the methods. Comments can be sent directly to the corresponding author or methodfeedback@aoac.org. Corresponding author’s e-mail: morgan.wallace@usa.dupont.com Appendices are available on the J. AOAC Int. website, http://aoac. publisher.ingentaconnect.com/content/aoac/jaoac DOI: 10.5740/jaoacint.13-407 tested in this study were artificially inoculated with a Salmonella strain at levels expected to produce low (0.2–2.0 CFU/test portion) or high (5 CFU/test portion) spike levels on the day of analysis. For each matrix, the collaborative study failed to show a statistically significant difference between the candidate method and the reference method using the probability of detection statistical model. A multilaboratory study was conducted to evaluate the ability of the DuPont™ BAX ® System Real-Time PCR Assay for Salmonella to detect the target species in a variety of foods and environmental surfaces. Internal validation studies were performed by DuPont Nutrition & Health on 24 different sample types to demonstrate the reliability of the test method among a wide variety of sample types. Two of these matrixes—pork and turkey frankfurters and pasteurized, not-from-concentrate orange juice without pulp—were each evaluated in 14 independent laboratories as part of the collaborative study to demonstrate repeatability and reproducibility of the internal laboratory results independent of the end user. Frankfurter samples were evaluated against the U.S. Department of Agriculture, Food Safety and Inspection Service reference method as a paired study, while orange juice samples were evaluated against the U.S. Food and Drug Administration reference method as an unpaired study, using a proprietary media for the test method. Samples

03/10/2019