AOAC-RI ERP Book MICRO Sept 2016.pdf

Document 2 of 2 – 3M Petrifilm Salmonella Express PTM Study Report

Table 22. 3M Petrifilm SALX Method Comparison POD Results for Raw Spinach (Internal Data) 1

3M Petrifilm SALX Method

Reference Method

x c

Strain MPN a /25g

N b

95% CI g

d

e

dPOD C f

95% CI

x

95% CI

Matrix Time Point

POD R

POD C

18 Hr Primary Enrichment – Salmonella 8 Hr 2 0 RV-R10 Enrichment Saint paul 18 Hr Primary Enrichment – ATCC

Fresh Spinach

5

0

0

0.00 - 0.43

0

0

0.00 - 0.43

0 -0.43 – 0.43

0

Vs. FDA/BAM

0.77 (0.41- 1.36)

20

7

0.35 0.18 - 0.57 10

0.5 0.30 – 0.70 0.15 -0.41 - 0.15

0

5

0

0

0.00 - 0.43

0

0

0.00 - 0.43

0 -0.43 – 0.43

24 Hr 2 0 RV-R10 Enrichment 24 Hr Primary Enrichment – 8 Hr 2 0 RV-R10 Enrichment 24 Hr Primary Enrichment – 24 Hr 2 0 RV-R10 Enrichment

0.77 (0.41- 1.36)

9712

20

7

0.35 0.18 - 0.57 10

0.5 0.30 – 0.70 0.15 -0.41 - 0.15

0

0

0.00 - 0.43

0

0

0.00 - 0.43

0 -0.43 – 0.43

0

5

0.77 (0.41- 1.36)

0.35 0.18 - 0.57 10

0.5 0.30 – 0.70 0.15 -0.41 - 0.15

20

7

0

5

0

0

0.00 - 0.43

0

0

0.00 - 0.43

0 -0.43 – 0.43

0.77 (0.41- 1.36)

20

7

0.35 0.18 - 0.57 10

0.5 0.30 – 0.70 0.15 -0.41 - 0.15

d POD C = Candidate method confirmed positive outcomes divided by the total number of trials e POD R = Reference method confirmed positive outcomes divided by the total number of trials f dPOD C = Difference between the candidate method confirmed results and candidate method confirmed result POD values g 95% CI = If the confidence interval of a dPOD does not contain zero, then the difference is statistically significant at the 5% level a MPN = Most Probable Number is based on the POD of reference method test portions across labs using the AOAC MPN calculator b N = Number of test potions c x = Number of positive test portions

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