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3M Petrifilm SALX Collaborative Study
July 2013
OMA-2013-July-XXX
DRAFT DOCUMENT
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1
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3
3.3
Study Schedule
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5
3.3.1
One matrix will be tested each week of the study. All data should be sent to the
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SD by the 4
th
week of study.
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3.3.2
The contract laboratory will prepare the test portions and ship the test portions
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refrigerated via overnight courier to the collaborators to arrive on a Friday. Test
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portion processing and analysis will begin on Monday. Data forms will be
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completed and faxed or emailed back to the co-Study Director by the following
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Friday.
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4.0
Test Portion Preparation
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4.1
Fresh raw ground beef and dry dog food will be obtained from local retail outlets and
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screened for the presence of
Salmonella
. Naturally contaminated test portions will be
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used if available at sufficient levels. Alternatively, the test portions will be artificially
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inoculated to meet the targets of 0.2-2.0 cfu/test portion for the low and 2 – 5 cfu/test
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portion for the high with the appropriate concentration of a wet inoculum for raw
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ground beef and a lyophilized inoculum for dry dog food.
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4.2
Preparation of test portions
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4.2.1
Ground beef:
A liquid inoculum will be added drop-wise to a bulk quantity of
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ground beef for each inoculation level - 0.2-2 cfu/25g and 2-5 cfu/25g. The bulk
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quantity will then be mixed to achieve equal distribution of analyte throughout.
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The test portions will be stored at 2-8
°
C for 72-96 h prior to testing.
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4.2.2
Dry dog food
: A wet inoculums in pellet form will be added to a bulk quantity of
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dry dog food for each inoculation level - 0.2-2 cfu/25g and 2-5 cfu/25g. The bulk
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quantity will then be mixed to achieve equal distribution of analyte throughout.
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The test portions will be stored at room temperature for 2 weeks prior to
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testing. Samples should be checked during the stabilization period to ensure
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MATRIX
Inoculating
organism
Target
Salmonella
Levels
# Test
Portions
(per method)
Test Portion
Codes
Reference
Method
Raw ground
beef (80/20)
25g-SALX
25g-MLG
S. enterica
subsp. Ohio
STS 81
(Fresh)
0 cfu/test portion
12
Random number
between 100-199
USDA/FSIS
MLG Ch.
4.06
0.2-2 cfu/test portion
12
2-5 cfu/test portion
12
Dry dog food
375g-SALX
25g-BAM
Salmonella
enterica
ser.
Poona
ATCC 4840
0 cfu/test portion
12
Random number
between 200-299
FDA/BAM
Chapter 5
0.2-2 cfu/test portion
12
2-5 cfu/test portion
12
OMAMAN-08/Collaborative Study Protocol
March 2014
Expert Review Panel Use Only
AOAC Research Institute
Expert Review Panel Use Only