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February 20, 2013
22
intervals obtained for the dPOD
C
values indicated no significant difference between the candidate and
1
reference method. A dPOD
CP
value of 0.00 with 95% confidence intervals of (-0.27, 0.27) were obtained
2
between presumptive and confirmed results using either the traditional or alternative confirmatory
3
procedure at both the 18 hour and 24 hour primary enrichment time points. The confidence intervals
4
obtained for dPOD
CP
indicated no significant difference between the presumptive and confirmed results.
5
6
Dry Dog Food
7
For dry dog food test portions, there were 16 confirmed positives by the 3M Petrifilm SALX System at both
8
the 18 hour and 24 hour primary enrichment time points and 14 confirmed positives the FDA/BAM
9
method. All un-inoculated control samples were negative for both methods. A χ
2
value of 0.52 was
10
obtained between the reference and candidate method using both the alternative and traditional
11
confirmation procedures, indicating no significant difference between the candidate and reference
12
methods at either of the time points.
13
14
For the low level inoculum, a dPOD
C
value of 0.10 with 95% confidence intervals of (-0.17, 0.35) was
15
obtained between the reference method and candidate method samples confirmed following either the
16
traditional or alternative confirmation procedure at both the 18 hour and 24 hour primary enrichment time
17
points. The confidence intervals obtained for dPOD
C
indicated no significant difference between the two
18
methods. A dPOD
CP
value of 0.00 with 95% confidence intervals of (-0.25, 0.25) was obtained between
19
presumptive and confirmed results using either the traditional or alternative confirmation procedure for
20
both the 18 hour and 24 hour primary enrichment time points. The confidence intervals obtained for
21
dPOD
CP
indicated no significant difference between the presumptive and confirmed results.
22
23
Stainless Steel Environmental Surface
24
For stainless steel environmental surfaces, there were 6 confirmed positives for the 3M Petrifilm SALX
25
System at both the 18 hour and 24 hour primary enrichment time points and 7 confirmed positives for the
26
FDA/BAM method. All un-inoculated control samples were negative for both methods. A χ
2
value of 0.11
27
was obtained between the reference and candidate method using both the traditional and alternative
28
confirmation procedures, indicating no significant difference between the candidate and reference
29
methods at any of the time points.
30
31
For the low level inoculum, a dPOD
C
value of -0.05 with 95% confidence intervals of (-0.32, 0.23) was
32
obtained between the reference method and candidate method samples confirmed using either the
33
traditional or alternative confirmation at both 18 hour and 24 hour primary enrichment time points. The
34
confidence intervals obtained for dPOD
C
indicated no significant difference between the two methods. A
35
dPOD
CP
value of 0.00 with 95% confidence intervals of (-0.27, 0.27) was obtained between presumptive and
36
confirmed results using either the traditional or alternative confirmation procedure for both the 18 hour
37
and 24 hour primary enrichment time points. The confidence intervals obtained for dPOD
CP
indicated no
38
significant difference between the presumptive and confirmed results.
39
40
Cooked Chicken Nuggets
41
For cooked chicken nugget test portions, there were 6 confirmed positives by the 3M Petrifilm SALX
42
method at both the 18 hour and 24 hour primary enrichment time points and 6 confirmed positives the
43
USDA/FSIS-MLG method. All un-inoculated control samples were negative for both methods. A χ
2
value of
44
0.0 was obtained between the reference and candidate method using both the traditional and alternative
45
confirmation procedures, indicating no significant difference between the candidate and reference
46
methods at any of the time points.
47