4. AOACRIMicroMethods-2018Awards

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454 B ird et al .: J ournal of AOAC I nternational V ol . 100, N o . 2, 2017

FOOD BIOLOGICAL CONTAMINANTS

Evaluation of the 3M™Molecular Detection Assay (MDA) 2 – Listeria monocytogenes for the Detection of Listeria monocytogenes in a Variety of Foods and Select Environmental Surfaces: Collaborative Study, First Action 2016.08 P atrick B ird , J onathan F lannery , E rin C rowley , J ames A gin , and D avid G oins Q Laboratories, Inc., 1400 Harrison Ave, Cincinnati, OH 45214 L isa M onteroso 3M Food Safety Department, 3M Center, Bldg 260-6B-01, St. Paul, MN 55144 Collaborators: C. Barnes; B. Bastin; D. Baumler; D. Bosco; A. Brandt; R. Brooks; E. Budge; A. Calle; D. Campos; C. Chavarria; C. Diaz Proano; Z. Geurin; C. Gies; F. Hernandez; D. Isfort; C. Lopez; L. Ma; E. Maranan; Z. Metz; J. Miller; A. Repeck; B. Schindler; M. Shekhawat; E. Sjogren; R. Smith; C. Timmons; G. Trevino; J. Walia; D. Wood; C. Zook

The 3M™ Molecular Detection Assay (MDA) 2 – Listeria monocytogenes uses loop-mediated isothermal amplification of unique DNA target sequences combined with bioluminescence to rapidly detect Listeria monocytogenes in a broad range of food types and on environmental surfaces. Using an unpaired study design, technicians from 13 laboratories located in the United States and Canada compared the 3M MDA 2 – Listeria monocytogenes to the U.S. Department of Agriculture Food Safety Inspection Service Microbiology Laboratory Guidebook Chapter 8.09 “Isolation and Identification of Listeria monocytogenes from Red Meat, Poultry, and Egg Products, and Environmental Samples” reference method for the detection of L. monocytogenes in deli turkey and raw chicken breast fillet. Each matrix was evaluated at three levels of contamination: an uninoculated control level (0 CFU/test portion), a low inoculum level (0.2–2 CFU/test portion), and a high inoculum level (2–5 CFU/test portion). Statistical analysis was conducted according to the probability of detection (POD) statistical model. Results obtained for the low inoculum level test portions produced a difference in the collaborating laboratory POD (dLPOD) value of 0.04 with a 95% confidence interval of (−0.08, 0.17) for deli turkey, indicating that the difference between methods was not statistically significant at the 0.05 probability level. For raw chicken breast fillet, Received July 25, 2016. Accepted by AH September 30, 2016. This method was approved by the Expert Review Panel for Microbiology Methods for Food and Environmental Surfaces as First Action. The Expert Review Panel for Microbiology Methods for Food and Environmental Surfaces 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 for 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: pbird@qlaboratories.com Supplemental information is available on the J. AOAC Int. Web site, http://aoac.publisher.ingentaconnect.com/content/aoac/jaoac DOI: 10.5740/jaoacint.16-0234

a dLPOD value of 0.16 with a 95% confidence interval of (0.04, 0.28) indicated a statistically significant difference, with an observed higher proportion of positive results by the candidate method compared to the reference method. L isteria monocytogenes is a highly pathogenic microorganism that contaminates food and can cause noninvasive gastroenteritis and the severe life-threatening illness referred to as listeriosis (1). Although rare, listeriosis is associated with high hospitalization and mortality rates (2). L. monocytogenes is ubiquitous in the environment, often found in soil, water, sewage, and damp environments, making it difficult to control in the food processing environment (1). The organism’s ability to survive in processing facilities has led to some highly publicized recent outbreaks, specifically in ice cream and packaged salads (3). The 3M ™ Molecular Detection Assay (MDA) 2 – Listeria monocytogenes method, using a combination of bioluminescence and isothermal amplification of nucleic acid sequences, allows for the rapid and specific detection of L. monocytogenes in a broad range of food types and environmental surfaces after a 24–32 h pre-enrichment. After enrichment, samples are evaluated using the 3M MDA 2 – Listeria monocytogenes on the 3M Molecular Detection System (MDS). Presumptive positive results are reported in real time, whereas negative results are displayed after completion of the assay, in approximately 75 min. Prior to the collaborative study, the 3M MDA 2 – Listeria monocytogenes method was validated according to AOAC INTERNATIONAL guidelines (4) in a harmonized AOAC Performance Tested Method SM (PTM) and Official Methods of Analysis SM study. The objective of the PTM study was to demonstrate that the 3M MDA 2 – Listeria monocytogenes method could detect L. monocytogenes in a variety of food matrixes and on select environmental surfaces as claimed by the manufacturer. For the 3M MDA 2 – Listeria monocytogenes PTM evaluation, 14 matrixes were evaluated: hot dogs (25 and 125g), salmon (25 g), deli turkey (25 and 125 g), cottage cheese (25 g), chocolate milk (25 mL), vanilla ice cream (25 g), queso fresco (25 g), bagged raw spinach (25 g), romaine lettuce (25 g),

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