Micro December 2018

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Table 2018.1A Interlaboratory Study Results of 3M Petrifilm Rapid E. coli /Coliform Count Plate vs. FDA BAM Chapter 4

3M Petrifilm Rapid E. coli /Coliform Count Plate - Coliform (35 o C)

FDA BAM Chapter 4 Coliform

Difference of Means b

Difference of Means c 95% LCL, UCL

Mean Log 10 CFU/g

Mean Log 10 CFU/g

Matrix

Lot

N a

s r

s R

Lot

N a

s r

s R

Uninoculated

9 9 9 9 9 9 9 9

0.000 1.645 2.687 3.458 0.000 1.422 2.298 3.236

0.00 0.22 0.12 0.10 0.00 0.22 0.12 0.14

0.00 0.25 0.16 0.17 0.00 0.31 0.26 0.22

Uninoculated

9 9 9 9 9 9 9 9

0.000 1.617 2.660 3.474 0.000 1.448 2.292 3.219

0.00 0.18 0.10 0.12 0.00 0.20 0.11 0.15

0.00 0.31 0.12 0.17 0.00 0.32 0.22 0.17

0.00 -0.28 -0.28 0.02 0.00 0.02 -0.01 -0.02

0.00, 0.00 -0.20, 0.14 -0.09, 0.03 -0.06, 0.10 0.00, 0.00 -0.17, 0.22 -0.12, 0.11 -0.14, 0.10

Low

Low

Dry Pet Kibble

Medium

Medium

High

High

Difference of Means b

Difference of Means c 95% LCL, UCL

3M Petrifilm Rapid E. coli /Coliform Count Plate – E. coli (35 o C)

FDA BAM Chapter 4 E. coli

Uninoculated

Uninoculated

Low

Low

Dry Pet Kibble

Medium

Medium

High

High

a Number of collaborators that reported complete results. b ADifference of means <0.5 indicates no statistically significant difference between methods c 95% Lower and Upper Confidence Limits s r – Repeatability s R – Reproducibility

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