4. AOACRIMicroMethods-2018Awards

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observed for each matrix collaboratively studied, the S L (between-laboratory effect components of S R ) being zero in both data sets at each partial response spike level. This acceptable interlaboratory reproducibility is supported by the insignificant homogeneity test P T values (>0.1), which suggest that the laboratory POD values are not significantly different when allowance is made for the sampling variability. While interpretation of this latter test is subject to the study design, 10 or more laboratories with 12 replicate sample portions per level for each of three levels (high, low, and unspiked) per laboratory is deemed adequate for such studies. The graphical representation of the data (Appendix 4, Figure 1) demonstrates that the dose-response curve for each matrix encompasses the partial response region required for qualitative detection method analysis. The 95% confidence interval of each dPOD value determined at each concentration contains zero, which is indicative of no significant difference between the candidate and reference methods and between the candidate presumptive result and candidate confirmed result. Within the statistical constraints of these studies, no differences were found between the reference culture-based methods and the alternative BAX System method. These results indicate that the alternative method can be used to allow uncontaminated food to be released rapidly from a manufacturer’s control and prevents Salmonella -contaminated foods from entering commerce. Furthermore, this test method can be a valuable tool for outbreak investigations when food contamination events occur. Collaborator feedback indicated that the method was easy to use and that the clear yes/no results provided by the BAX System software were appreciated. Time and labor savings were cited as key advantages of the test method over the reference culture methods. No negative feedback regarding the method was provided by any of the collaborators. The DuPont BAX System Real-Time PCR Assay for Salmonella was adopted as Official First Action status for the detection of Salmonella in a variety of foods, including raw ground beef, ground beef with soy, beef trim, frankfurters, shrimp, ground turkey, chicken wings, poultry rinse, dried eggs, shell eggs, fresh bagged lettuce, frozen peas, orange juice, cream cheese, nonfat dry milk, ice cream, peanut butter, cocoa, white pepper, infant formula, and dry pet food, and on stainless steel, ceramic tile, and plastic surfaces. value Conclusions

Bryan Dieckelman, Deibel Laboratories (Lincolnwood, IL) Tom Donohue, LeAnne Hahn, and Catherine Churchill, Deibel Laboratories (Madison, WI) Hesham Elgaali, Indiana Department of Health (Indianapolis, IN) Willis Fedio, New Mexico State University (Las Cruces, NM) Elizabeth Galbraith, DuPont Nutrition & Health (Waukesha, WI) Brian Kupski, Silliker Laboratories (Crete, IL) Kristina McCallum and Dominika Kondratko, Colorado Department of Agriculture (Denver, CO) Guy McWhorter, ABC Research Laboratories (Gainesville, FL) Joe Meyer and Demi Swift, Covance Laboratories (Monona, WI) Roy Radcliff and Dorn Clark, Jr, Marshfield Food Safety (Marshfield, WI) Dora Rodgers, Samantha Scott, and Joseph Putrow,Wisconsin Department of Agriculture (Madison, WI) Leslie Thompson, AEGIS FOOD TESTING Laboratories (North Sioux City, SD) We would also like to thank Nicolette Blubaugh (DuPont Nutrition & Health, Wilmington, DE) for invaluable assistance in the preparation of this manuscript and Maria Nelson (AOAC INTERNATIONAL, Gaithersburg, MD) for her expertise and assistance in the design and execution of this study. (1) U.S. Department of Agriculture-Food Safety and Inspection Service (2011) Microbiology Laboratory Guidebook, Chapter 4.05, Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg and Catfish Products, http://www.fsis. usda.gov/PDF/MLG_4_05.pdf  (2) U.S. Food and Drug Administration (2011) Bacteriological Analytical Manual , Chapter 5, Salmonella , http://www.fda.gov/ food/foodscienceresearch/laboratorymethods/ucm070149  (3) Reid, A. (2009) MFHPB-20, Isolation and Identification of Salmonella from Food and Environmental Samples. In: Health Canada Compendium, Vol. 3, Laboratory Procedures for the Microbiological Examination of Foods, Health Canada, Health Products and Food Branch, http://www.hc-sc.gc.ca/fn-an/res- rech/analy-meth/microbio/volume2/mfhpb20-01-eng.php  (4)  Official Methods of Analysis (2012) 19th Ed., AOAC INTERNATIONAL, Gaithersburg, MD, Appendix J: AOAC INTERNATIONAL Methods Committee Guidelines for Validation of Microbiological Methods for Food and Environmental Surfaces, www.eoma.aoac.org/app_j.pdf  (5) Least Cost Formulations, Ltd, MPN Calculator-Version 1.6, http://www.lcfltd.com/customer/LCFMPNCalculator.exe  (6) Least Cost Formulations, Ltd (2011) AOAC Binary Data Interlaboratory Study Workbook, http://lcfltd.com/aoac/aoac- binary-v2-2.xls References

Acknowledgments

We sincerely thank the following collaborators for their dedicated participation in this study:

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