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8
1
Environmental samples
2
(d)
Sample collection devices can be a sponge hydrated with a neutralizing solution to
3
inactivate the effects of the sanitizers. 3M recommends the use of a biocide-free
4
cellulose sponge. Neutralizing solution can be Dey-Engley (D/E) Neutralizing Broth
5
or Letheen broth. It is recommended to sanitize the area after sampling.
6
7
WARNING: Should you select to use Neutralizing Buffer (NB) that contains aryl
8
sulfonate complex as the hydrating solution for the sponge, it is required to perform a
9
1:2 dilution (1-part sample into 1-part sterile enrichment broth) of the enriched
10
environmental sample before testing in order to reduce the risks associated with a
11
false-negative result leading to the release of contaminated product. Another option is
12
to transfer 10 µL of the NB enrichment in the LS tubes.
13
14
(e)
The recommended size of the sampling area to verify the presence or absence of the
15
pathogen on the surface is at least 100 cm
2
(10 cm x 10 cm or 4”x4”). When sampling
16
with a sponge, cover the entire area going in two directions (left to right then up and
17
down) or collect environmental samples following your current sampling protocol or
18
according to the FDA BAM, USDA FSIS MLG or ISO 18593 [11] guidelines.
19
1.
Allow the Demi-Fraser Broth enrichment medium (includes ferric ammonium
20
citrate) to equilibrate to ambient laboratory temperature (20-25
o
C).
21
2.
Aseptically combine the enrichment medium and sample according to Table
2A
.
22
3.
Homogenize thoroughly by
blendingvortexing or ,
stomaching
, or hand mixing
23
for 2 ±0.2 minutes. Incubate at 37 ±1°C for 24-30 hours.
24
25
E.
P
REPARATION OF THE
3M™M
OLECULAR
D
ETECTION
S
PEED
L
OADER
T
RAY
26
(a)
Wet a cloth or paper towel with a 1-5% (v:v in water) household bleach solution and
27
wipe the 3M™ Molecular Detection Speed Loader Tray.
28
(b)
Rinse the 3M Molecular Detection Speed Loader Tray with water.
29
(c)
Use a disposable towel to wipe the 3M Molecular Detection Speed Loader Tray dry.
30
(d)
Ensure the 3M Molecular Detection Speed Loader Tray is dry before use
31
32
Specific Instructions for Validated Methods
33
AOAC® Performance Tested Method
SM
#111501
34
35
36
37
Formatted:
Line spacing: single