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of
38
0.43), indicating no statistical difference between the candidate and reference method. A POD
CP
value and a POD
CC
value of 1.00 was obtained with 95% confidence intervals of (0.57, 1.00). A dPOD
C
value of 0.00 was obtained with
95% confidence intervals of (-0.43, 0.43), indicating no statistical difference between the candidate method
presumptive and confirmed results.
Inclusivity/Exclusivity Results
For both modified protocols, all 105
Salmonella
inclusivity isolates were detected by the 3M MDA
Salmonella
method. The candidate method also correctly excluded all 31 exclusivity isolates. Detailed results are presented in
Tables P and Q of the Appendix.
Independent Laboratory - Method Comparison
The Independent Laboratory study was performed as outlined above with data collection points for the 3M MDS at
10 and 18 hours for ground beef and 4 and 24 hours for head on shrimp.
Raw Ground Beef – 375 g
For the low-level after enrichment 10 hours there were 8 presumptive and 12 confirmed positives for the candidate
method. There were 9 confirmed positives for the USDA/FSIS reference method. A POD
C
value of 0.40 was
obtained with 95% confidence intervals of (0.22, 0.61). A POD
R
value of 0.45 was obtained with 95% confidence
intervals of (0.26, 0.66). A dPOD
C
value of -0.05 was obtained with 95% confidence intervals of (-0.33, 0.24),
indicating no statistical difference between the candidate and reference method. For the low inoculation level a
POD
CP
value of 0.40 (0.22, 0.61) and a POD
CC
value of 0.60 (0.39, 0.78) was obtained. A dPOD
CP
value of -0.20 (-
0.46, 0.10) indicating no statistical difference between the candidate method presumptive and confirmed results.
After 18 enrichment hours there were 10 presumptive and 12 confirmed positives for the candidate method. There
were 9 confirmed positives for the USDA/FSIS reference method. A POD
C
value of 0.50 was obtained with 95%
confidence intervals of (0.30, 0.70). A POD
R
value of 0.45 was obtained with 95% confidence intervals of (0.26,
0.66). A dPOD
C
value of 0.05 was obtained with 95% confidence intervals of (-0.24, 0.33), indicating no statistical
difference between the candidate and reference method. For the low inoculation level a POD
CP
value of 0.50 (0.30,
0.70) and a POD
CC
value of 0.60 (0.39, 0.78) was obtained. A dPOD
CP
value of -0.10 (-0.37, 0.19) indicating no
statistical difference between the candidate method presumptive and confirmed results.
For the high inoculation level at 10 and 18 hours, there were 5 presumptive and confirmed positives for the
candidate method and 5 confirmed positives for the reference method. A POD
C
and POD
R
value of 1.00 was
obtained with 95% confidence intervals of (0.57, 1.00). A dPOD
C
value of 0.00 was obtained with 95% confidence
intervals of (-0.43, 0.43), indicating no statistical difference between the candidate and reference method. A POD
CP
value and a POD
CC
value of 1.00 was obtained with 95% confidence intervals of (0.57, 1.00). A dPOD
C
value of
0.00 was obtained with 95% confidence intervals of (-0.43, 0.43), indicating no statistical difference between the
candidate method presumptive and confirmed results.
Raw Head-on Shrimp from 4 and 24 Hour RV 10 Broth
For the low-level after a 4 hour incubation in RV10 broth, there were 5 presumptive and 4 confirmed positives for
the candidate method and 6 confirmed positives following the FDA/BAM reference method. A POD
C
value of 0.20
was obtained with 95% confidence intervals of (0.08, 0.42). A POD
R
value of 0.20 was obtained with 95%
confidence intervals of (0.08, 0.42). A dPOD
C
value of -0.10 was obtained with 95% confidence intervals of (-0.35,
0.17) indicating no statistical difference between the candidate and reference method. For the low inoculation level
on the head-on shrimp after a 4 hour incubation in RV10 broth a POD
CP
value of 0.25 was obtained with 95%
confidence intervals of (0.11, 0.47) . A POD
CC
value of 0.20 was obtained with 95% confidence intervals of (0.08,
0.42). A dPOD
CP
value of 0.05 with 95% confidence intervals of (-0.21, 0.30) indicating no statistical difference
between the candidate method presumptive and confirmed results.
2013.09 /PTM Matrix Extension Report
March 2014
Expert Review Panel Use Only
AOAC Research Institute
Expert Review Panel Use Only