70 / 596
29
2.
Aseptically combine the enrichment medium and sample according to Table 2. For all meat
1
and highly particulate samples, the use of filter bags is recommended.
2
3.
Homogenize thoroughly by blending, stomaching, or hand mixing for 2 ±0.2 minutes.
3
Incubate at 37 ±1°C according to Table 2.
4
4.
For raw dairy products, transfer 0.1 mL of the primary enrichment into 10 mL of Fraser
5
Broth. Incubate at 37 ±1°C for 20-24 hours.
6
7
Environmental samples
8
Sample collection devices can be a sponge hydrated with a neutralizing solution to inactivate
9
the effects of the sanitizers. 3M recommends the use of a biocide-free cellulose sponge.
10
Neutralizing solution can be Dey-Engley (D/E) Neutralizing Broth or Letheen broth. It is
11
recommended to sanitize the area after sampling.
12
13
14
WARNING: Should you select to use Neutralizing Buffer (NB) that contains aryl sulfonate
15
complex as the hydrating solution for the sponge, it is required to perform a 1:2 dilution (1 part
16
sample into 1 part sterile enrichment broth) of the enriched environmental sample before testing
17
in order to reduce the risks associated with a false-negative result leading to the release of
18
contaminated product.
19
20
The recommended size of the sampling area to verify the presence or absence of the pathogen
21
on the surface is at least 100 cm
2
(10 cm x 10 cm or 4”x4”). When sampling with a sponge,
22
cover the entire area going in two directions (left to right then up and down) or collect
23
environmental samples following your current sampling protocol or according to the FDA BAM
24
(1)
, USDA FSIS MLG
(2)
or ISO 18593
(6)
guidelines.
25
26
1.
Allow the Demi-Fraser Broth enrichment medium (includes ferric ammonium citrate) to
27
equilibrate to ambient laboratory temperature.
28
2.
Aseptically combine the enrichment medium and sample according to Table 2.
29
3.
Homogenize thoroughly by blending, stomaching, or hand mixing for 2 ±0.2 minutes.
30
Incubate at 37 ±1°C for 24-30 hours.
31
32
33
AOAC Research Institute
Expert Review Panel Use Only
OMAMAN-29/OMAMAN-30 Combined Collaborative Study Protocol
OMA ERP - June 2016
ERP Use Only