628-629 / 1195
Table 6.
Comparison of LPT and AOAC 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
Test Portion
Size
Contaminatio
n Level
MPN/test
portion
Total
Samples
VIDAS LPT
Reference
Method
Chi
Sq.
b
Positive Confirme
d
Vanilla ice
cream
L. ivanovii
ATCC
a
13124
25g
Uninoculated
NA
5
0
0
0
-
Low
1.31
20
18
18
15
1.52
Soft cheese
(fresh queso)
L.
monocytogenes
ATCC 19114
25g
Uninoculated
NA
5
0
0
0
-
Low
0.79
20
9
9
11
0.39
Soft cheese
(fresh queso)
L.
monocytogenes
ATCC 19114
125g
Uninoculated
NA
5
0
0
0
-
Low
0.79
20
11
11
11
0