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3M MDA2 E. coli O157:H7 Collaborative Study
May 2016
OMA-2016-May-XXXX
DRAFT DOCUMENT
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Shipment Schedule
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Test portions will be shipped by overnight express courier to arrive the day before initiation of analysis.
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If the test portions do not arrive by the normal delivery time one day prior to analysis, please contact a
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co-Study Director. All test portions will be shipped refrigerated.
Analysis of test portions must be
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initiated on the day scheduled by the Study Director. Test kits will be sent directly from 3M.
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Proposed analysis schedule
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Food
Date Shipped
Date Tested
Raw ground beef
325 g
Thursday
Monday
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Test Portion Receipt
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Note condition of package on the data sheets and notify the Study Director if any packages appear to
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have been compromised or if the food product does not arrive in the appropriate condition. All products
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should arrive cold to the touch and should be stored at 4
C (refrigerated) until the day of analysis.
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Test Portion Analysis
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Collaborators will be provided with enough test portion to test using the 3M MDA2 -
E. coli
O157
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(including H7) method and the reference method. For raw ground beef testing, collaborators will
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receive: 36 x 325g (3M) and 36 x 325g (MLG). See Appendix 8.5 for detailed instructions on analysis.
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Please review the reference methods carefully before initiating analysis.
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One additional 60 g control (negative) test portion will be provided to each collaborator for each matrix
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to determine the total plate count on the day of analysis. One temperature control sample will also be
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included in the shipment to document the temperature of the sample upon receipt. Record all results on
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the data sheet provided.
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1.
3M Molecular Detection Assay 2 -
E. coli
O157 (including H7) Method
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1.1.
Pre-warm 3M buffered peptone water BPW ISO enrichment medium to the incubation
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temperature: 41.5 ±1°C. For meat and highly particulate samples, filter bags are recommended.
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1.2.
Aseptically add 325 g test portion to 975 mL BPW ISO. Homogenize the sample for 2 ± 0.2 min.
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Incubate at 41.5 ±1°C.
After 10 hr
, pull a sample from ground beef enrichment to run the 3M
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Molecular Detection Instrument following the 3M Molecular Detection System User Manual –
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Reserving enriched test portion for confirmation.
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1.3.
Confirmation of alternative method
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All samples, regardless of presumptive result, must be
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confirmed starting with step 2.3 below.
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2.
USDA/FSIS Reference Method, MLG online Chapter 5.09 –
E. coli
O157:H7
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2.1.
Add 325g into 975 mL mTSB. Stomach each test portion for approximately two minutes.
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Incubate at 42
1
C for 15-24 h.
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2.2.
Perform the screening test for
E. coli
O157:H7/non-motile following the manufacturer
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instructions for the screening method listed in USDA FSIS MLG 5A.
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OMAMAN-35 B: Collaborative Study Protocol
ERP USE ONLY
January 2017
AOAC Research Institute
Expert Review Panel Use Only