34 / 199
B
ird
et al
.:
J
ournal of
AOAC I
nternational
V
ol
.
100, N
o
.
1, 2017
95
of the inoculating organism in the uninoculated control samples.
Further analysis at the coordinating laboratory confirmed cross-
contamination of the uninoculated controls. Due to this issue,
the data submitted from Laboratory 10 was not used in the
statistical analysis. All other laboratories submitted data for
both methods being evaluated. The MPN levels obtained for
this matrix with 95% confidence intervals were 0.66 CFU/test
portion (0.51, 0.83) for the low level and 6.24 CFU/test portion
(3.58, 10.88) for the high level.
For the low inoculum level, 88 of 132 test portions (POD
CP
of 0.67) were reported as presumptive positive by the 3M
MDA 2–
Listeria
method with 86 of 132 test portions (POD
CC
of 0.65) confirming positive. For samples that produced
presumptive positive results on the 3M MDA 2–
Listeria
Figure 1. (A) POD values of the candidate method versus the reference method for 125 g deli turkey. (B) dLPOD values of the candidate
method versus the reference method for 125 g deli turkey.
A
B