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3M Petrifilm SALX Collaborative Study
July 2013
OMA-2013-July-XXX
DRAFT DOCUMENT
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5.5.3
Sterile serological pipettes. –
capable of 1mL
1
5.5.4
Pipettes
. – capable of 100µL
2
5.5.5
Sterile pipette tips.
– capable of 100µL
3
5.5.6
Stomacher®
. – Seward or equivalent
4
5.5.7
Filter Stomacher® bags
. - Seward or equivalent
5
5.5.8
Incubators
. – capable of maintaining 41.5° ± 1°C
6
5.5.9
Incubator -capable of maintaining 35°C± 1°C
7
5.5.10
5.5.10Waterbath- capable of maintaining 42°C± 0.2°C(circulating,
8
thermostatically controlled)
9
5.5.11
Freezer
. – capable of maintaining -10° to -20°C, for storing opened SALX
10
pouches , hydrated SALX plates, SALX plates after incubation
11
5.5.12
5.5.11Refrigerator
. – capable of maintaining 2° - 8°C, for storing unopened
12
3M SALX plates and SALX disks
13
5.5.13
Sterile distilled water
14
5.5.14
Sterile reverse osmosis water
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5.5.15
Sterile Butterfield’s Phosphate Diluent
16
5.5.16
3M Petrifilm Flat Spreader
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5.6
Enrichment
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5.6.1.1
Raw ground beef (25g, high microbial load)
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5.6.1.1.1
Aseptically add the 25g test portion to 225 mL pre-warmed (41.5°C)
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3M
Salmonella
Enrichment Base with supplement.
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5.6.1.1.2
Mix in a Stomacher® bag with filter for 2 min.
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5.6.1.1.3
Incubate 18-24 hr at 41.5 ± 1°C.
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5.6.1.1.4
After primary enrichment incubation, transfer 0.1 mL of the primary
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enrichment into 10.0 mL Rappaport-Vassiliadis R10 (R-V R10) Broth.
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Incubate at 41.5 ± 1.0°C for 8-24 hours.
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5.6.1.2
Dry dog food (375g, low microbial load)
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5.6.1.2.1
Aseptically add the 375g test portion to 3375 mL pre-warmed
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(41.5°C) 3M
Salmonella
Enrichment Base with supplement.
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5.6.1.2.2
Mix in a Stomacher® bag with filter for 2 min.
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5.6.1.2.3
Incubate 18-24 hr at 41.5 ± 1°C.
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5.7
Plate Hydration
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5.7.1
Use prescribed sterile diluents to hydrate the 3M Petrifilm SALX Plates:
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Butterfield’s Phosphate Diluent, distilled water, or reverse osmosis water.
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5.7.2
Place the 3M Petrifilm SALX Plate on a flat, level surface (figure A).
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5.7.3
Lift the top film and with the pipette perpendicular dispense 2.0 mL ± 0.1 mL of
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sterile diluent onto the center of bottom film (figure B). Do not close the top
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film before dispensing the entire 2.0 mL volume.
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5.7.4
Gently roll down the top film onto the diluent to prevent trapping air bubbles
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(figure C).
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5.7.5
Place the 3M
TM
Petrifilm
TM
Flat Spreader (Catalog #6425) on the center of the
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plate. Press gently on the center of the spreader to distribute the diluent evenly.
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OMAMAN-08/Collaborative Study Protocol
March 2014
Expert Review Panel Use Only
AOAC Research Institute
Expert Review Panel Use Only