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454
B
ird
et al
.:
J
ournal of
AOAC I
nternational
V
ol
.
100, N
o
.
2, 2017
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,
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),
FOOD BIOLOGICAL CONTAMINANTS
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.comSupplemental information is available on the
J. AOAC Int.
Web site,
http://aoac.publisher.ingentaconnect.com/content/aoac/jaoacDOI: 10.5740/jaoacint.16-0234