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Revised Mar 2014
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Evaluation of Modification of the 3M
™
Molecular Detection Assay
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(MDA)
Salmonella
for the Detection of
Salmonella
in Selected
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Foods:
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Collaborative Study
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Patrick Bird, Kiel Fisher, Megan Boyle, Travis Huffman, M. Joseph Benzinger, Jr., Paige
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Bedinghaus, Jonathon Flannery, Erin Crowley, James Agin, David Goins
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Q Laboratories, Inc., 1400 Harrison Ave, Cincinnati, OH 45214
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DeAnn Benesh, John David
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3M Food Safety Department,
3MCenter – Bldg. 260-6B-01, St. Paul, MN 55144
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Collaborators: K. Newman, V. Gill, I. Mello, M. Ontiberos, C. Gwinn, S. Moosekian, J. Marchent, J.
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Dyszel, M. Vross, K. Blanchard, D. Lewis, M. Horan, B. Stawick, J. Ruebl, K. Rajkowski,
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A. Morey, S. Montez, J. Jurgens, L. Thompson, M. Bandu, M. Oltman, D. Bosco, R. Brooks, S.
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Luce, H. Dammann, D. Clark Jr., W. McMahon, D. Awad, M. Kelly, M. Greenwell
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The 3M
™
Molecular Detection Assay (MDA)
Salmonella
utilizes isothermal
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amplification of nucleic acid sequences with high specificity, efficiency, rapidity
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and bioluminescence to detect amplification of
Salmonella
spp. in food, food-
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related and environmental samples after enrichment. The 3M MDA
Salmonella
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method was compared using an unpaired study design in a multi-laboratory
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collaborative study to the United States Department of Agriculture /Food Safety
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Inspection Service(USDA/FSIS) MicrobiologyLaboratory Guidebook (MLG) 4.05
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(2011)
Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized
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Egg and Catfish Products
for raw ground beefand the Food &Drug Administration
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(FDA)/BacteriologicalAnalytical Manual (BAM) Chapter 5
Salmonella
reference
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method for wet dog food following the current AOAC Guidelines. A total of 20
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laboratories participated. For the 3M MDA
Salmonella
method, raw ground beef
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was analyzed using 25 g test portions, and wet dog food was analyzed using 375
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g test portions. For the reference methods, 25 g test portions of each matrix were
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analyzed. Each matrix was artificially contaminated with
Salmonella
at 3
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inoculation levels: an un-inoculated control level (0 colony forming units
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(CFU)/test portion), a low inoculum level (0.2-2 CFU/test portion) and a high
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inoculum level (2-5 CFU/test portion). In this study, 1,512 unpaired replicate
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samples were analyzed. Statistical analysis was conducted according to the
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Probability of Detection (POD). For the low-level raw ground beef test portions,
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the following dLPOD values with 95% confidence intervals were obtained: -0.01, (-
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0.14, +0.12). For the low-level wet dog food test portions, the following dLPOD
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with 95% confidence intervals were obtained: -0.04, (-0.16, +0.09). No significant
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differences were observed in the number of positive samples detected by the 3M
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MDA
Salmonella
method versuseither the USDA/FSIS-MLG or FDA/BAM methods.
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A method modification and matrix extension study of the previously approved
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AOAC OMA 2013.09 was conducted and approval of the modification was
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received on Date TBD.
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