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3M Petrifilm SALX Collaborative Study
July 2013
OMA-2013-July-XXX
DRAFT DOCUMENT
2
Appendix 8.6 – Flow Diagram for Dry Dog Food
1
(37
2
Dry dog food
25g + 225ml
Lactose broth,
Blend 2 min and let stand 60±5 min at room temp
Mix and adjust pH to 6.8±0.2 if necessary
24±2h h at 35°C
0.1ml sample + 10ml
RV, 24±2h at
42±0.2°C in
circulating waterbath
BAM
375g + 3375mL 3M Salmonella Enrichment +
Supplement (prewarmed to 41.5C)
Homogenize 2 min
18-24h at 41.5±1°C
3M
0.1ml sample +
10ml RV, 24±2h at
42±0.2°C in
circulating
waterbath
Transfer typical colonies
to TSI/LIA slants
24±2h at 35°C
1.0ml sample +
10ml TT, 24±2h
at 35±2°C
Biochemical/serological
confirmation on all
enrichments according to
FDA-BAM
Streak to XLD, HE, BS-
incubate according to specific
plate instructions
3M SALX Method
3M SALX Method
Confirmation
Reference Method
Confirmation
Transfer typical colonies
to TSI/LIA slants
24±2h at 35°C
Biochemical/serological
confirmation on all
enrichments according to
FDA-BAM
Streak to XLD, HE, BS -
incubate according to specific
plate instructions
1.0ml sample +
10ml TT, 24±2h
at 35±2°C
Hydrate SALX plate with
2.0 mL DI water, close top
film gently, use 3M
spreader to distribute
diluent evenly, let sit on
bench at least 1 hr prior to
use, protected from light
Streak enriched sample onto
gel of SALX plate. Close topfilm
and incubate 41.5±1°C for
24±2 hr.
Transfer typical colonies
to TSI/LIA slants
24±2h at 35±1°C
Biochemical/serological
confirmations on all
enrichments according to
FDA-BAM
Place room temperature SALX
confirmation disk onto SALX
plate, under top film and incubate
41.5±1°C for 4-5 h
Circle presumptive Salmonella
colonies (red to brown with
yellow zone or gas bubble)
Record sample as positive if
typical colonies appear on
SALX plate
Record confirmed + results:
green to blue, blue to dark blue
or black or have a blue
precipitate around
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4
OMAMAN-08/Collaborative Study Protocol
March 2014
Expert Review Panel Use Only
AOAC Research Institute
Expert Review Panel Use Only