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the reverse transformed mean difference \were calculated on each contamination level for each
1
matrix to determine if a statistical significant difference existed between the methods.
2
Repeatability (s
r
), reproducibility (s
R
), standard deviation of repeatability (RSD
r
) and standard
3
deviation of reproducibility (RSD
R
) were determined for each contamination level for both the
4
3M Petrifilm RYM Count Plate and FDA BAM/ISO 21527 methods. The results of the
5
interlaboratory data analyses are presented in Tables 2014.1 and 2014.2. The result for each
6
collaborating laboratory’s aerobic plate count analysis for each matrix is presented in Table
7
2014.3.
8
9
10
11
Frozen Raw Ground Beef Patties (77% lean)
12
13
Frozen raw ground beef patties test portions were inoculated at a low, medium and high
14
contamination level and were analyzed (Tables 2-5) for the enumeration of yeast and mold.
15
Uninoculated controls were included in each analysis. Fifteen laboratories participated in the
16
analysis of this matrix.
17
18
3M RYM Count Plate incubated at 25
o
C and enumerated at 48 hours
19
20
The mean log
10
counts of the 3M Petrifilm RYM Count Plate and FDA BAM/ISO 21527
21
results were compared statistically. One (1) laboratory in the FDA BAM/ISO 21527 low
22
contamination level was identified as an outlier as defined by the Cochran’s tests for outliers.
23
However, no evidence of physical cause or suspicion of cause was noted and it was determined
24
that they would be included in the statistical analysis.
25
There were no statistically significant differences at the 5% level in log transformed means
26
between the 3M Petrifilm RYM Count Plate and FDA BAM/ISO 21257 methods, at any of the
27
three contamination levels.
28
.
29
30
3M RYM Count Plate incubated at 25
o
C and enumerated at 60 hours
31
32
The mean log
10
counts of the 3M Petrifilm RYM Count Plate and FDA BAM/ISO 21527
33
results were compared statistically. One (1) laboratory in the FDA BAM/ISO 21527 low
34
contamination level was identified as an outlier as defined by the Cochran’s tests for outliers.
35
However, no evidence of physical cause or suspicion of cause was noted and it was determined
36
that they would be included in the statistical analysis.
37
There were no statistically significant differences at the 5% level in log transformed means
38
between the 3M Petrifilm RYM Count Plate and FDA BAM/ISO 21257 methods, at any of the
39
three contamination levels.
40
41
3M RYM Count Plate incubated at 28
o
C and enumerated at 48 hours
42
43
The mean log
10
counts of the 3M Petrifilm RYM Count Plate and FDA BAM/ISO 21527
44
results were compared statistically. One (1) laboratory in the FDA BAM/ISO 21527 low
45
contamination level was identified as an outlier as defined by the Cochran’s tests for outliers.
46
However, no evidence of physical cause or suspicion of cause was noted and it was determined
47
that they would be included in the statistical analysis.
48
Candidates for 2016 Method of the Year
82