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3M Molecular Detection Assay Salmonella Collaborative Study July 2012
OMA-2012-July-XXX
by the USDA/FSIS MLG method. Collaborators will receive 72 samples for wet 1
pet food: 12 uninoculated controls, 12 low level (target 0.2 – 2.0 cfu/test portion), 2
and 12 high level (target 2 – 5 cfu/test portion) for two different test portion sizes: 3
25g and 375g. The 375g test portions will be tested using the 3M Molecular 4
Detection Assay Salmonella and the 25g test portions will be tested by the FDA- 5
BAM method. See flow diagrams 8.5 and 8.6 for the study diagrams. Each 6
laboratory will test all test portions. Each test portions will be inoculated with a 7
variety of Salmonella spp. as listed in Table 1, randomized and blind-coded for 8
analysis. 9
10
Table 1. Overview of Study Design 11
12
13
14
3.4 Study Schedule 15
16
3.4.1 One matrix will be tested each week of the study. All data should be sent 17
to the Study Director by the 4th week of study. 18
19
3.4.2 The contract laboratory will prepare the test portions and ship the test 20
portions refrigerated via overnight courier to the collaborators to arrive on 21
a Friday. Test portion processing and analysis will begin on Monday. 22
Data forms will be completed and faxed or emailed back to the co-Study 23
Director by the following Friday. 24
25
4.0 Test Portion Preparation 26
27
4.1 Products will be obtained from local retail outlets. All food types will be 28
screened for the presence of Salmonella. Naturally contaminated test portions 29
will be used if available at sufficient levels. Alternatively, the test portions will 30
be artificially inoculated to meet the targets of 0.2-2.0 cfu/test portion for the low 31
and 2 – 5 cfu/test portion for the high with the appropriate concentration of a wet 32
MATRIX Inoculating
organism
Target Salmonella
Levels
# Test
Portions
(per
method)
Test Portion
Codes
Reference
Method
Raw ground beef
(80/20)
25 – 3M MDA
25g – USDA
S. enterica
ser. Ohio
STS 81
0 cfu/test portion 12
Random
number
between
100-199
USDA/FSIS
MLG 0.2-2 cfu/test portion 12
2-5 cfu/test portion 12
Wet pet food
375g – 3M MDA
25g – BAM
S. enterica
ser. Poona
NCTC 4840
0 cfu/test portion 12 Random
number
between
200-299
FDA-BAM 0.2-2 cfu/test portion 12
2-5 cfu/test portion 12
DRAFT DOCUMENT 5