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B
ird
et al
.:
J
ournal of
AOAC I
nternational
V
ol
.
99, N
o
.
3, 2016
671
interlaboratory data analyses are presented in Tables
2015.13A
and
2015.13B
.
Raw Easy-Peel Shrimp
Raw easy-peel shrimp test portions were evaluated at a
low, medium, and high contamination level for the presence of
naturally occurring aerobic bacteria. Replicate 3M Petrifilm RAC
Plates were evaluated at both 32 and 35°C (Tables
2015.13D
and
E
) Sixteen laboratories participated in the analysis of this
matrix, with all 16 laboratories submitting data.
3M Petrifilm RAC Plate Incubated at 32°C
For the 3M Petrifilm RAC Plate low and medium
contamination levels and for the FDA BAM low and high
contamination levels, one outlier laboratory was identified
by the Cochran’s tests for outliers. However, no evidence of
physical cause or suspicion of cause was noted and it was
determined that the data would be included in the statistical
analysis.
There were no statistically significant differences between the
3M Petrifilm RAC Plate and FDABAM methods as determined
by the 95% CI of the differences of means at any of the three
contamination levels.
3M Petrifilm RAC Plate Incubated at 35°C
For the 3M Petrifilm RAC Plate medium contamination level
and for the FDA BAM low and high contamination levels, one
outlier laboratory was identified by the Cochran’s tests for
outliers. However, no evidence of physical cause or suspicion
of cause was noted and it was determined that the data would be
included in the statistical analysis.
Figure 3. Youden plots for 3M Petrifilm RAC Plate and SMEDP results for pasteurized skim milk.
Figure 2. Youden plots for 3M Petrifilm RAC Plate and FDA BAM results for raw easy-peel shrimp evaluated at 35°C.