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816
B
ird
et al
.
:
J
ournal of
AOAC I
nternational
V
ol
. 96, N
o
. 4, 2013
Raw Ground Beef (375 g Test Portions)
Raw ground beef test portions were inoculated at a low and
a high level, and analyzed (Tables 4 and 5) for the detection of
Salmonella
spp. Uninoculated controls were included in each
analysis. Fourteen laboratories participated in the analysis of
this matrix; the results of 11 laboratories were included in the
statistical analysis. Laboratory 8 reported that it was unable to
confirm samples via serological testing and indicated that it did
not conduct the alternative confirmation of the VIDAS SPT
samples. Therefore, its results were not included in statistical
analysis. Laboratory 5 detected the presence of
Salmonella
spp.
in their reference method uninoculated control replicates;
therefore, its results were not included for statistical analysis.
Laboratory 2 detected the presence of
Salmonella
spp. in their
VIDAS SPT replicates following the traditional confirmation
procedure, and Laboratory 12 detected the presence of
Salmonella
spp. in the confirmation of VIDAS SPT replicates
following the alternative confirmation procedure. Therefore,
their results were not included in the statistical analysis for
those categories. The MPN levels obtained for this test portion,
with 95% confidence intervals, were 0.72 CFU/test portion
Table 2. Individual collaborator results for raw ground beef (25 g test portions) using traditional confirmation
a
High-level test portions
Low-level test portions
Uninoculated test portions
Lab 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12
VIDAS SPT (traditional confirmation)
1 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
2 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
3 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
4 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
5 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
6 + + + + + + + + + + + + + + + + + + + –
b
+ + + + – – – – – – – – – – – –
7 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
8
c
NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
9 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
10 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
11 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
12
c
+ + + + + + + + + + + + + + + + + + + + + + + + – – –
c
– – – – – – – – –
13 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
14 + + + + + + + + + + + + + + + + + + + + + + + + – – – – – – – – – – – –
15 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
USDA/FSIS-MLG
1 + + + + + + + + + + + + + – + – + + + – – + – + – – – – – – – – – – – –
2 + + + + + + + + + + + + + + + – – – + + – + – – – – – – – – – – – – – –
3 – + + + + + + + + + + + + + – + + + + + + – – – – – – – – – – – – – – –
4 + + + + + + + + + + + + – + + + + + – + + – + + – – – – – – – – – – – –
5 + + + + + + + + + + + + + + + + + + – + – + + + – – – – – – – – – – – –
6 + + + + + + – + + + + – – – – – + + + + – – + – – – – – – – – – – – – –
7 + + + + + + + + + + + + – + + – – – + – – + – + – – – – – – – – – – – –
8
c
NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
9 + + + + + + + + + + + + + – – + + + + + – + – + – – – – –
d
– – – – – – –
10 – + + + + + + + + + – – + – – – – + + + + + – + – – – – – – – – – – – –
11 + + + + + + + + + + + + + + – + – + + – – + – – – – – – – – – – – – – –
12
c
+ + + + + + + + + + + + – + – + + + – – + – – – – – – – – – – – – – – –
13 + + + + + + + + + + + + – + + – + + – – + + – – – – – – – – – – – – – –
14 + + + + + + + + + + + + + + – + – + – + – – + + – – – – – – – – – – – –
15 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
a
+ = Salmonella spp. were detected in samples; – = Salmonella spp. were not detected in sample; NA = laboratory did not participate in this matrix or
results were not received.
b
Sample was presumptive positive on VIDAS SPT, but confirmed negative indicating a false-positive result.
c
Results were not used in statistical analysis due to laboratory error.
d
Sample was confirmed negative on XLT4 and BGS, but confirmed positive on ASAP agar.
Candidates for 2016 Method of the Year
307