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following the reference method.Detailed results of the POD analyses are presented in Tables 11
1
and 15.
2
3
All five uninoculated control test portions were negative by both the MDA2 -
Listeria
4
monocytogenes
assay and the corresponding reference method for each matrix above.
5
6
7
Product Consistency (Lot-to-Lot) and Stability Studies
8
9
Methodology
10
Three lots of MDA2 –
Listeriamonocytogenes
test kits, 1 newly manufactured, 1 at the middle of
11
its expiration, and 1 at or slightly beyond expiration was analyzed to determine the stability of
12
the assay. For the MDA2 –
Listeriamonocytogenes
test kit, one
Listeria monocytogenes
ATCC
13
7644 isolate was analyzed at a fractional positive level (2-8 positives), and testing 10 replicates.
14
One non-
Listeriamonocytogenes
isolate,
Enterococcus faecalis
ATCC 29212, was analyzed at the
15
growth level achieved in a non-selective broth, testing 5 replicates.
16
17
Results
18
For the lot-to-lot/stability evaluation of the MDA2 -
Listeria monocytogenes
assay, there were 6
19
presumptive positives out of 10 replicates for all three lots at the low inoculation level. For the 5
20
uninoculated control test portions, there were 0 presumptive positives out of 5 replicates for all
21
three lots.The five control test portions were negative. See Tables 16 for lot-to-lot/stability
22
results.
23
24
Robustness Study
25
26
Methodology
27
The robustness evaluated the ability of the method to remain unaffected by minor variations in
28
method parameters that might be expected to occur when the method is performed by an end
29
user. Three different parameters were evaluated, which are presented in Table 17.For each
30
parameter, one
Listeria monocytogenes
ATCC 7644isolate was analyzed at a fractional positive
31
level (2-8 positives), testing 10 replicates. One non-
Listeriamonocytogenes
isolate,
Enterococcus
32
faecalis
ATCC 29212, was analyzed at the growth level achieved in a non-selective broth, testing
33
5 replicates.
34
35
Results
36
37
For the robustness analysis of the MDA2 -
Listeria monocytogenes
assay, there were 6
38
presumptive positives out of 10 replicates for each variation evaluated. For the 5 control test
39
portions, there were 0 presumptive positives out of 5 replicates. See Table 17 for robustness
40
results.
41
42
Independent Laboratory Observations
43
44
The results of this study demonstrate the ability of the MDA2
Listeria monocytogenes
to detect
45
the presence of
Listeria monocytogenes
in various food matrices and select environmental
46
AOAC Research Institute
Expert Review Panel Use Only
OMAMAN-30 D/ PTM Validation Report 081501
OMA ERP - June 2016
ERP Use Only