17 / 199
994
B
ird
et al
.:
J
ournal of
aoaC i
nternational
V
ol
.
99, n
o
.
4, 2016
2 –
Salmonella
method, with 83 test portions (POD
CC
of 0.53)
confirming positive. For samples that produced presumptive
positive results on the 3M MDA 2 –
Salmonella
method,
82 samples confirmed positive (POD
C
of 0.53). For test portions
evaluated by the USDA/FSIS MLG reference method, 77 of
156 test portions produced positive results. A dLPOD
C
value
of 0.03 (95% confidence interval, −0.10 to 0.16) was obtained
between the candidate and reference method, indicating no
statistical significant difference between the two methods. A
dLPOD
CP
value of 0.00 (95% confidence interval, −0.14 to
0.14) was obtained between presumptive and confirmed results,
indicating no statistically significant difference between the
presumptive and confirmed results.
For the high inoculum level, 155 of 156 test portions (POD
CP
of 0.99) were reported as presumptive positive by the 3M MDA
2 –
Salmonella
method, with 155 test portions (POD
CC
of 0.99)
confirming positive. For samples that produced presumptive
positive results on the 3M MDA 2 –
Salmonella
method, 155
samples confirmed positive (POD
C
of 0.99). For test portions
evaluated by the USDA/FSIS MLG reference method, 156 of
156 test portions produced positive results. A dLPOD
C
value
of −0.01 (95% confidence interval, −0.04 to 0.02) was obtained
between the candidate and reference method, indicating no
statistical significant difference between the two methods. A
dLPOD
CP
value of 0.00 (95% confidence interval, −0.03 to
0.03) was obtained between presumptive and confirmed results,
indicating no statistically significant difference between the
presumptive and confirmed results.
For the uninoculated controls, 4 of 156 samples (POD
CP
of
0.03) produced a presumptive positive result by the 3M MDA
2 –
Salmonella
method, with three test portions (POD
CC
of 0.02)
confirming positive. For samples that produced presumptive
positive results on the 3M MDA 2 –
Salmonella
method, two
samples confirmed positive (POD
C
of 0.01). For test portions
evaluated by the USDA/FSIS MLG reference method, 2 of 156
test portions produced positive results. A dLPOD
C
value of 0.00
(95% confidence interval, −0.03 to 0.03) was obtained between
the candidate and reference method, indicating no statistical
significant difference between the two methods. A dLPOD
CP
value of 0.01 (95% confidence interval, −0.03 to 0.05) was
obtained between presumptive and confirmed results, indicating
no statistically significant difference between the presumptive
and confirmed results.
Detailed results of the POD statistical analysis are presented
in Table
2016.01C
and Figures 1 and 2.
Table 5.
Results of Aerobic Plate Count for Collaborating
Laboratories
Laboratory
Raw Ground Beef
(CFU/g)
Creamy Peanut
Butter (CFU/g)
1
5.8 x 10
5
2.2 x 10
2
2
4.4 x 10
6
3.4 x 10
2
3
4.0 x 10
1
3.4 x 10
2
4
8.3 x 10
6
1.0 x 10
2
5
NA
NA
6
3.3 x 10
7
1.9 x 10
2
7
NA
1.2 x 10
2
8
2.7 x 10
6
1.9 x 10
2
9
4.4 x 10
5
3.2 x 10
2
10
NA
3.1 x 10
2
11
1.7 x 10
6
NA
12
4.5 x 10
5
4.1 x 10
2
13
6.6 x 10
3
2.2 x 10
1
14
1.3 x 10
6
3.1 x 10
2
15
1.2 x 10
5
1.0 x 10
1
16
2.3 x 10
5
NA
Figure 1. POD values of candidate method versus reference method for 325 g raw ground beef (73% lean).