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CONFIDENTIAL INFORMATION
Page 6 of 13
positive ‘screening stage’ and a positive ‘confirmation stage’), true negatives
(samples with a negative ‘screening stage’ and a negative ‘confirmation stage’),
false positive (samples with a
positive ‘screening stage’ but a negative
‘confirmation stage’) and false negatives (samples with a negative ‘screening
stage’ but a positive ‘confirmation stage’
) for the candidate method testing of
frozen blueberries is provided in Table 4. The AOAC fractional positive criterion
(POD between 0.25 and 0.75) was met, providing evidence that the inoculation
procedure was successful for the frozen blueberry matrix. Additionally, no false
positives or false negatives were identified when comparing the
‘
screening stage
’
and
‘
confirmation stage
’
of the candidate method.
As described in Section 2.7, the results presented here were statistically
analyzed according to the POD methods of the 2012 version of the AOAC
International Methods Committee Guidelines for Validation of Microbiological
Methods for Food and Environmental Surfaces document (1). The POD
CP
,
POD
CC
, dPOD
CP
, POD
C
, POD
R
, and dPOD
C
values calculated at each level of
inoculation for the candidate method and the reference method testing of
spinach, and their corresponding 95% confidence intervals, are provided below in
Table 5. Review of the POD calculation outcomes for the frozen blueberry
candidate method (25 g Frozen Blueberries Analyzed via the 3M
TM
MDA) and
reference method (25 g Frozen Blueberries Analyzed via the FDA BAM Ch. 4A),
shows that the 95% confidence intervals contained 0.000 at all inoculation levels
for the dPOD
CP
, comparing the ‘screening stage’ and ‘confirmation stage’ of the
candidate method, and the dPOD
C
, comparing the candidate method and
reference method. Because of this, for the candidate method, the POD
CP
values
were not significantly different from their corresponding POD
CC
values. Based on
this outcome, it can be stated that the probability of detecting a positive result in
the “screening stage” of the candidate method was not significantly different fro
m
the probability of detecting a positive result in its “confirmation stage” at any of
the inoculation levels tested. Additionally, for the candidate method versus the
reference method, the POD
C
values were not significantly different from their
corresponding POD
R
values. Based on these outcomes, by fulfilling the criteria
to contain 0.000 within the 95% confidence intervals, it can be stated that the
probability of detecting a positive result in the candidate method was not
significantly different from the probability of detecting a positive results in the
reference method.