626-627 / 1195
Table 5.
Comparison of LPT and FDA-BAM Methods for Detection of
Listeria
in Food
a
American Type Culture Collection
b
X
2
is defined by Mantel-Haenszel as (n-1)(AF-(B+C+D)E)
2
/(A+B+C+D)(A+E)B+C+D+F)(E+F) where n+A+B+C+D+E+F. A X
2
value greater than 3.84 indicates significance at
p
>0.05.
Matrix/Strain
Test
Portion Size
Contaminatio
n Level
MPN/25g
Total
Samples
VIDAS LPT
Reference
Method
Chi
Sq.
b
Positive Confirmed
Cooked shrimp
L. grayii
ATCC
a
700545
25g
Uninoculated
NA
5
0
0
0
-
Low
0.95
20
16
16
13
1.10
Smoked salmon
L. monocytogenes
ATCC 19115
25g
Uninoculated
NA
5
0
0
0
-
Low
0.95
20
14
14
15
0.12
Cantaloupe
melon
L. welshimeri
ATCC 43549
25g
Uninoculated
NA
5
0
0
0
-
Low
12
cfu/sample
20
12
12
10
0.40
Bagged mixed
salad
L. monocytogenes
ATCC 1971
25g
Uninoculated
NA
5
0
0
0
-
Low
1.31
20
20
20
15
5.57
Peanut butter
L. seeligeri
ATCC 35697
25g
Uninoculated
NA
5
0
0
0
-
Low
1.13
20
15
15
16
0.14
Black pepper
L. innocua
ATCC 33090
25g
Uninoculated
NA
5
0
0
0
-
Low
0.79
20
8
8
10
0.40