118-119 / 471
Table 2014.1. Interlaboratory study results of 3M Petrifilm RYM vs. the FDA BAM and ISO 21527 methods For Frozen Raw Ground Beef Patties
3M Petrifilm RYM Method
FDA BAM/ISO 21527 Methods
a
p-
value
d
Difference
of Means
e
Reverse
Transformed
Mean Difference
f
Matrix
Lot
N
b
Mean
c
s
r
s
R
Lot
N
b
Mean
c
s
r
s
R
Frozen Raw
Ground
Beef Patties
25
o
C
48 hours
Control 11(0)
<
1.00
-
-
Control
11(0)
<
1.00
-
-
-
-
-
Low
11(0)
2.12
0.41
0.41
Low
11(1)
2.07
0.36
0.38
0.5323
0.05
14.34
Medium 11(0)
3.52
0.10
0.10
Medium
11(0)
3.47
0.09
0.11
0.1637
0.05
360.10
High
11(0)
4.65
0.13
0.14
High
11(0)
4.59
0.10
0.14
0.2266
0.06
5763.84
Frozen Raw
Ground
Beef Patties
25
o
C
60 hours
Control 11(0)
<
1.00
-
-
Control
11(0)
<
1.00
-
-
-
-
-
Low
11(0)
2.14
0.36
g
0.37
Low
11(1)
2.07
0.36
0.38
0.3773
0.07
20.55
Medium 11(0)
3.52
0.10
0.10
Medium
11(0)
3.47
0.09
0.11
0.1573
0.05
360.10
High
11(0)
4.65
0.14
0.15
High
11(0)
4.59
0.10
0.14
0.1750
0.06
5763.84
Frozen Raw
Ground
Beef Patties
28
o
C
48 hours
Control 11(0)
<
1.00
-
-
Control
11(0)
<
1.00
-
-
-
-
-
Low
11(0)
2.17
0.29
g
0.30
Low
11(1)
2.07
0.36
0.38
0.1391
0.10
30.42
Medium 11(0)
3.53
0.10
0.10
Medium
11(0)
3.47
0.09
0.11
0.0824
0.06
437.23
High
11(0)
4.67
0.08
g
0.11
High
11(0)
4.59
0.10
0.14
0.0966
0.08
7869.00
Frozen Raw
Ground
Beef Patties
28
o
C
60 hours
Control 11(0)
<
1.00
-
-
Control
11(0)
<
1.00
-
-
-
-
-
Low
11(0)
2.16
0.29
g
0.29
Low
11(1)
2.07
0.36
0.38
0.1843
0.09
27.05
Medium 11(0)
3.53
0.09
0.10
Medium
11(0)
3.47
0.09
0.11
0.1095
0.06
437.23
High
11(0)
4.67
0.08
g
0.11
High
11(0)
4.59
0.10
0.14
0.1088
0.08
7869.00
a
Samples were analyzed by a harmonized FDA BAM Chapter 18 and
ISO 21527 methods using 0.1% peptone as the sample diluent
b
Number of laboratories that reported complete results. Outliers are
presented in parentheses.
c
Log
10
yeast and mold CFU/g.
d
Significant difference (p<0.05)
e
Significant difference if absolute value is >0.5
f
Results presented as CFU/g
g
Results indicate that the candidate method is more repeatable then the
reference methods
s
r
– Repeatability;
s
R
– Reproducibility;
1
Candidates for 2016 Method of the Year
96