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Table 31.
Comparison of repeatability between the 3M Petrifilm RYM
1
method ISO 21527:2008 part 1 and FDA-BAM Chapter 18.
2
Product
Level
Low
Medium
High
Low
Medium
High
48 Hr RYM vs Reference
Method Repeatability
3.24
1.96
4.00
48 Hr RYM vs Reference
Value Repeatability
2.25
1.96
4.00
Yogurt
1.56
1.23
1.56
1.56
2.25
4.00
Frozen Beef
Patty
3
4
Summary of Independent Laboratory Results
5
The low inoculated yogurt had a mean level of yeast of 2.3 Log CFU/g (Table 29). There was no
6
significant difference between the 48h RYM counts and the reference method or the 60h RYM and the
7
reference method (p>0.05). The medium inoculated yogurt had a mean level of yeast of 3.5 Log CFU/g.
8
There was no significant difference between the 48h RYM counts and the reference method or the 60h
9
RYM and the reference method (p>0.05). The high inoculated yogurt had a mean level of
10
yeast of 4.5 Log CFU/g. There was no significant difference between the 48h RYM counts and the
11
reference method or the 60h RYM and the reference method (p>0.05). The repeatability of all
12
methods was less than 0.1 and when compared between the RYM and the reference methods was
13
less than the critical value (<6.39, Table 31).
14
15
The low inoculated frozen ground beef patties had a mean level of yeast of 1.9Log CFU/g (Table 30).
16
There was no significant difference between the 48h RYM counts and the reference method or the 60h
17
RYM and the reference method (p>0.05). The medium inoculated frozen ground beef patties had a
18
mean level of yeast of 2.78-2.95 Log CFU/g. There was a significant difference between the counts on
19
the 48h RYM and the 60h RYM and those on the reference method (p<0.05) with the RYM plates with a
20
higher number of organisms. The high inoculated yogurt had a mean level of yeast of 3.63-3.81 Log
21
CFU/g. There was a significant difference between the counts on the 48h RYM and the 60h RYM and
22
those of the reference method (p<0.05) with the RYM plates with a higher number of organisms. The
23
repeatability of all methods was less than or equal to 0.1 and when compared between the RYM and
24
the reference methods was less than the critical value (<6.39, Table 31).
25
The independent laboratory stated that the 3M Petrifilm RYM Plate method:
26
41
AOAC Research Institute
Expert R view Panel Use Only
OMAMAN-16D/ PTM Report
ERP Use Only - December 2014