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3M Molecular Detection Assay Salmonella Collaborative Study
July 2012
OMA-2012-July-XXX
One additional 60 g control (negative) test portion will be provided to each collaborator for each
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matrix to determine the total plate count on the day of analysis. Use these results to determine
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the TT incubation temperature. One temperature control sample will also be included in the
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shipment to document the temperature of the sample upon receipt. Record all results on the data
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sheets provided.
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Food Type Reference
Reference
Pre-enrichment
3M MDA
Enrichment
Wet dog
food
BA
M 4Lactose broth
3M BPW ISO
Raw ground
beef
MLG
5BPW
3M BPW ISO
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Wet dog food – separate test portion preparations -
(See Appendix 8.5 for a flow diagram)
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NOTE
– use stomacher bag with filter for all 3M test portions.
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1.1
3M Molecular Detection Assay
Salmonella
To each 375g test portion, add 3375
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mL 3M BPW ISO. Homogenize each sample for approximately two minutes and
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incubate 18 h at 37 ± 1°C.
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1.2
Prepare the 3M Molecular Detection speed loader tray, chill block insert, heat
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block insert and instrument following the 3M Molecular Detection Assay
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Salmonella
Instuctions for Use [IFU] and 3M Molecular Detection Instrument
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manual.
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1.3
Transfer 20 µL enriched sample into a LS tube.
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1.4
Transfer 20 µL NC into a LS tube after all enriched samples have been
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completed.
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1.5
Invert 3-5 times and heat 15±1 min at 100±1°C.
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1.6
Place tubes (without rack lid) in chill block insert for 10±1 min.
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1.7
Replace rack lid and invert 3-5 times. Allow to sit on bench at least 5 min.
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1.8
Transfer 20 µL sample lysate from the upper portion of fluid in the LS tube into
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regent tube. Mix gently by pipetting up and down 5 times.
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1.9
Transfer 20 µL of NC lysate into a reagent tube.
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1.10
Transfer 20 µL of NC lysate into a Reagent Control (RC) tube.
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1.11
Load capped tubes into speed loader tray and close lid.
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1.12
Start assay.
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1.13
Validation Study Confirmation
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1.13.1
Using the primary enrichment (step 1.1 above), follow steps starting at 2.2
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below (secondary enrichments) to confirm each test portion, regardless of
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presumptive result.
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1.13.2
Transfer typical colonies to TSI/LIA slants. Incubate 35
±
1
°
C for 24
±
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2h.
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1.13.3
Confirm a minimum of one typical colony per sample with
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biochemical/serological procedures prescribed by the FDA-BAM method.
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4
http://www.fda.gov/Food/ScienceResearch/LaboratoryMethods/BacteriologicalAnalyticalManualBAM/ucm070149.htm5
http://www.fsis.usda.gov/PDF/MLG_4_05.pdfDRAFT DOCUMENT
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