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Evaluation of 3M
™
Molecular Detection Assay (MDA)
Listeria
for
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the Detection of
Listeria
speciesin SelectedFoods and Environmental
2
Surfaces:
3
Collaborative Study
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5
Patrick Bird, Jonathan Flannery, Erin Crowley, James Agin, David Goins
6
Q Laboratories, Inc., 1400 Harrison Ave, Cincinnati, OH 45214
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Lisa Monteroso, DeAnn Benesh
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3M Food Safety Department,
3MCenter – Bldg. 260-6B-01, St. Paul, MN 55144
10
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Collaborators: P. Fatemi, S. Spencer, J. Blumfield, A. Hankins, R. Dermer, N. Shipley, J. Williams,
12
A. Morris, R. Brooks, K. Powers, J. Picket, A. Thielen, L. Thompson, C. Lopez, A. Brandt, B.
13
Brahmanda, L. Hardrath, Y. Chen, A. Laasri, R. Brooks, D. Wood, A. Sweet, J. Schoeni, B. Kupski,
14
N. Cuthbert, B. Bastin
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The 3M™ Molecular Detection Assay (MDA)
Listeria
is used with the 3M™
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Molecular Detection System for the detection of
Listeria
species in food, food-
18
related, and environmental samples after enrichment. The assay utilizes loop-
19
mediated isothermal amplification to rapidly amplify
Listeria
target DNA with high
20
specificity and sensitivity, combined with bioluminescence to detect the
21
amplification. The 3M MDA
Listeria
method was evaluated using an unpaired
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study design in a multi-laboratory collaborative study and compared to the
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AOAC
®
Official Method of Analysis (OMA) 993.12
Listeria monocytogenes in Milk
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and Dairy Products
reference method for the detection of
Listeria
species infull
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fat (4% milk fat) cottage cheese (25 g test portions). A total of 15 laboratories
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located in the continental United States and Canada participated. Each matrix
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had 3 inoculation levels: an un-inoculated control level (0 colony forming units
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(CFU)/test portion), and two levels artificially contaminated with
Listeria
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monocytogenes,
a low inoculum level (0.2-2 CFU/test portion) and a high
30
inoculum level (2-5 CFU/test portion) using non-heat stressed
cells.Intotal,
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792unpaired replicate samples were analyzed. Statistical analysis was conducted
32
according to the Probability of Detection (POD).Results obtained for the low
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inoculum level test portions produced a dLPOD value with 95% confidence
34
intervals of -0.07, (-0.19, 0.06).Nostatistically significant differences were
35
observed in the number of positive samples detected by the 3M MDA
36
Listeria
method versustheAOAC OMA method.
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Listeria
is a Gram-positive, rod shaped bacteriumfound widespread in the environment and one
40
species,
Listeria monocytogenes
, is known to be the causative agent of listeriosis in humans [1].
41
Due to its high mortality rate, specificallyin susceptible individuals such as older adults, pregnant
42
women, newborns and adults with weakened immune systems, Listeriosis presents itself as an
43
important health problem in the United States, Canada and throughout the world [2].
Listeria’s
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ability to survive in extreme conditions, such as low temperature and a broadpH range (4.4 to
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Candidates for 2016 Method of the Year
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