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3M Petrifilm RYM Collaborative Study
June 2014
OMA-2014-June-XXX
beef
(80% lean,
20% fat)
ATCC 201382
~500 cfu/g
4
3
between 100-
199
~5000 cfu/g
4
3
Raw
almonds
Aspergillus
aculeatus
ATCC 56925
0 cfu/g
4
3
Random
number
between 200-
299
~50 cfu/g
4
3
~500 cfu/g
4
3
~5000 cfu/g
4
3
*Two plates incubated at 25°C and two plates incubated at 28°C
1.2.
Study Schedule
1.2.1.
One matrix will be tested each week of the study. All data should be sent
to the co-Study Director by the 3
rd
week of study.
1.2.2.
One co-Study Director will prepare the test portions and ship the test
portions refrigerated via overnight courier to the collaborators to arrive on
a Friday. Test portion processing and analysis will begin on Monday.
Data forms will be completed and faxed or emailed back to the co-Study
Director by the following Friday.
4.
Test Portion Preparation
4.1.
Matrix spiking
4.1.1.
Obtain 4 lots (~2100g/lot) of each of food product. Determine the
background levels of aerobic bacteria by Bacteriological Analytical
Manual Chapter 3 Aerobic Plate Count (January 2001) and any yeast/mold
counts by Bacteriological Analytical Manual Chapter 18: Yeasts, Molds
and Mycotoxins (April 2001).
.
4.1.2.
If the lots are naturally contaminated
, each lot should be manipulated
(temperature abused to increase levels or mixed to decrease levels) so as to
produce 4 different contamination levels. The goal is to have each batch
approximately 10-fold higher than the previous.
4.1.3.
If there is no natural contamination
in any of the 4 lots then all 4 lots
should be combined to form one large batch. It should then be divided into
4 sub-batches, 3 of which will need to be artificially contaminated with a
yeast or mold (Table 1) at the following levels targeted: low, 10-100 cfu/g;
medium: 100-1000 cfu/g; high: 1000-10,000 cfu/g
.
The fourth batch will
serve as the control.
4.1.3.1.
Raw frozen ground beef
(80% lean/20% fat) will be
thawed, inoculated with a liquid inoculum (
Trichosporon mucoides
6
DRAFT DOCUMENT
AOAC Research Institute
Expert Review Panel Use Only
OMAMAN-16A/ Collaborative Study Protocol
ERP Use Only - December 2014