347 / 596
9
In AOAC PTM studies, the 3M Molecular Detection Assay 2 –
Listeria
was found to be an
1
effective method for the detection of
Listeria
species
.
The matrices tested in the study are
2
shown in Table
2A
. The limit of detection of the 3M Molecular Detection Assay 2 –
Listeria
3
method is 1-5 colony forming units per validated test portion size (in Table
2A
).
4
5
6
Table
2A
:
Enrichment protocols using Demi-Fraser Broth at 37 ± 1 °C
7
according to AOAC Performance Tested
SM
Certificate #111501
8
9
Sample Matrix
Sample Size
Enrichment
Broth Volume
(mL)
Enrichment
Time (hr)
Beef hot dogs, Queso
Fresco, Vanilla Ice
Cream, 4% Milk Fat
Cottage Cheese, 3%
chocolate whole milk,
romaine lettuce, bagged
raw spinach, cold
smoked salmon
25 g
225
24-30
Raw chicken
25 g
475
28-32
Deli turkey
125 g
1125
24-30
Cantaloupe
a
Whole
melon
Enough
volume to
allow melon to
float
26-30
Environmental
samples:
Stainless
steel
1 sponge
225
24-30
Sealed
concrete
1 sponge
100
24-30
Plastic
b
1 swab
10
24-30
All samples for the AOAC validation were homogenized by stomaching unless otherwise noted.
10
a = Homogenize sample by hand mixing
11
12
b = Homogenize sample by vortexing
13
F. P
REPARATION OF THE
3M™M
OLECULAR
D
ETECTION
H
EAT
B
LOCK
I
NSERT
14
Formatted:
Superscript
Formatted:
Space After: 10 pt, Line spacing:
single
Formatted:
Indent: Left: 0.5", First line: 0.5",
Line spacing: single
Formatted:
Space After: 10 pt, Line spacing:
single
Formatted:
Font: (Default) Times New
Roman, 9 pt, Not Bold, Not Small caps