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The 3M Molecular Detection Assay 2 –
Listeriamonocytogenes
method may generate
Listeria
2
monocytogenes
to levels sufficient to cause stillbirths and fatalities in pregnant women and the
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immunocompromised, if exposed.
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To reduce the risks associated with exposure to chemicals and biohazards:
•
It is strongly recommended that female laboratory staff be informed of the risk to a
developing fetus resulting from infection of the mother through exposure to
Listeria
monocytogenes
•
Perform pathogentesting in a properly equipped laboratory under the control of trained
personnel
•
Always follow standard laboratory safety practices, including wearing appropriate protective
apparel and eye protection while handling reagents and contaminated samples
•
Avoid contact with the contents of the enrichment media and reagent tubes after amplification
•
Dispose of enriched samples according to current industry standards
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Enrichment
Sample Preparation
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3M recommends the use of Demi-Fraser Broth (with addition of ferric ammonium citrate) for the
8
enrichment of food and environmental samples.Table 1 presents guidance for the enrichment of
9
food and environmental samples. It is the user’s responsibility to validate alternate sampling
10
protocols or dilution ratios to ensure this test method meets the user’s criteria.
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12
Foods
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a)
Allow the Demi-Fraser Broth enrichment medium to equilibrate to ambient laboratory
14
temperature.
15
b)
Aseptically combine the enrichment medium and sample according to Table 1. For all meat
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and highly particulate samples, the use of filter bags is recommended.
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c)
Homogenize thoroughly by blending, stomaching, or hand mixing for 2 ±0.2 minutes.
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Incubate at 37 ±1°C according to Table 1.
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Environmental samples
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Sample collection devices can be a sponge
hydrated
with a neutralizing solution to inactivate the
22
effects of the sanitizers. 3M recommends the use of a biocide-free cellulose sponge. Neutralizing
23
solution can be Dey-Engley (D/E) Neutralizing Broth or Letheen broth. It is recommended to
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sanitize the area after sampling.
25
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The recommended size of the sampling area
for verifying
the presence or absence of the pathogen
27
on the surface is at least 100 cm
2
(10 cm x 10 cm or 4”x4”). When sampling with a sponge,
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cover the entire area going in two directions (left to right then up and down) or collect
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environmental samples following your current sampling protocol or according to the FDA BAM,
30
USDA FSIS MLG or ISO 18593 (7) guidelines.
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1.
Allow the Demi-Fraser Broth enrichment medium to equilibrate to ambient laboratory
33
temperature.
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2.
Aseptically combine the enrichment medium and sample according to Table 1.
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3.
Homogenize thoroughly by blending, stomaching, or hand mixing for 2 ±0.2 minutes.
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AOAC Research Institute
Expert Review Panel Use Only
OMAMAN-30 D/ PTM Validation Report 081501
OMA ERP - June 2016
ERP Use Only