782-783 / 1195
1
Table 3. Individual Collaborator Results for Queso Fresco
a
, (25 gram Test Portions)
High-Level Test Portions
Low Level Test Portions
Un-inoculated Test Portions
1
2
3
4
5
6
7
8
9 10 11 12 1
2
3
4
5
6
7
8
9 10 11 12 1
2
3
4
5
6
7
8
9 10 11 12
VIDAS LMX
b
Lab
1
+ +
+
+
+
+
+
+
+
+
+
+
+
+
-
+
-
+
-
+
-
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
2
+ +
+
+
+
+
+
+
+
+
+
+
+
+
-
+
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
3
+ +
+
+
+
+
+
+
+
+
+
+
+
-
+
-
+
+
+
+
+
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
4
+ +
+
+
+
+
+
+
+
+
+
+
+
+
-
-
-
-
-
+
-
-
c
-
c
-
-
-
-
-
-
-
-
-
-
-
-
5
+ +
+
+
+
+
+
+
+
+
+
+
-
-
+
-
+
+
+
-
-
-
+
-
-
-
-
-
-
-
-
-
-
-
-
-
6
+ +
+
+
+
+
+
+
+
+
+
+
+
-
-
+
+
+
-
-
-
+
+
-
-
-
-
-
-
-
-
-
-
-
-
-
7
+ +
+
+
+
+
+
+
+
+
+
+
+
+
-
-
+
-
-
+
+
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
8
+ +
+
+
+
+
+
+
+
+
+
+
-
+
-
+
+
+
-
-
-
-
+
+
-
-
-
-
-
-
-
-
-
-
-
-
9
+ +
+
+
+
+
+
+
+
+
+
+
-
+
+
+
-
-
-
-
-
+
+
-
-
-
-
-
-
-
-
-
-
-
-
-
10
+ +
+
+
+
+
+
+
+
+
+
+
+
+
-
+
+
-
-
-
-
+
+
-
-
-
-
-
-
-
-
-
-
-
-
-
11
j
+ +
+
+
+
+
+
+
+
+
+
+
+
+
+
d
+
-
-
-
+
e
+
-
-
-
-
-
-
-
-
-
-
-
+
d
-
-
+
d
12
+ +
+
+
+
+
+
+
+
+
+
+
-
-
+
+
+
-
-
+
+
-
+
+
-
-
-
-
-
-
-
-
-
-
-
-
13
+ +
+
+
+
+
+
+
+
+
+
+
-
-
-
+
+
+
-
+
+
+
-
+
-
-
-
-
-
-
-
-
-
-
-
-
14
+ +
+
+
+
+
+
+
+
+
+
+
+
-
+
-
+
-
-
+
-
+
-
+
-
-
-
-
-
-
-
-
-
-
-
-
AOAC OMA 993.12
1
+ +
+
+
+
+
+
+
+
+
+
+
-
-
+
-
-
+
+ +
+
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
2
+ +
+
+
+
+
+
+
+
+
+
+
-
+
-
-
-
-
-
+
+
+
-
+
-
-
-
-
-
-
-
-
-
-
-
-
3
+ +
+
+
+
+
+
+
+
+
+
+
-
+
-
-
-
+
+
+
+
+
-
+
-
-
-
-
-
-
-
-
-
-
-
-
4
+ +
+
+
+
+
+
+
+
-
+
+
-
-
+
-
-
-
+
+
-
-
+
-
-
-
-
-
-
-
-
-
-
-
-
-
5
+ +
+
+
+
+
+
+
+
+
+
+
+
-
-
-
+
+
+
-
+
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
6
+ +
+
+
+
+
+
+
+
+
-
-
-
+
-
+
+
-
-
+
+
-
+
+
-
-
-
-
-
-
-
-
-
-
-
-
7
+ +
+
+
+
+
+
+
+
+
+
+
-
-
-
-
-
-
+
+
+
-
-
+
-
-
-
-
-
-
-
-
-
-
-
-
8
+ +
+
+
+
+
+
+
+
+
+
+
-
+
-
+
+
+
-
-
-
-
+
-
-
-
-
-
-
-
-
-
-
-
-
-
9
+ +
+
+
+
+
+
+
+
+
+
+
-
-
+
+
-
+
-
-
-
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
10 + +
+
+
+
+
+
+
+
+
+
+
-
+
+
+
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
-
-
-
11
j
+ +
+
+
+
+
+
+
+
+
+
+
+
+
f
+
f
+
+
g
+
+
+
h
+
+
-
+
g
-
+
g
-
-
-
+
g
-
-
+
i
-
-
-
12 + +
+
+
+
+
+
+
+
+
+
+
-
+
-
-
+
-
-
-
+
+
-
+
-
-
-
-
-
-
-
-
-
-
-
-
13 + +
+
+
+
+
+
+
+
+
+
+
+
+
+
+
-
+
-
-
-
-
+
+
-
-
-
-
-
-
-
-
-
-
-
-
14 + +
+
+
+
+
+
+
+
+
+
+
-
+
-
+
-
+
-
-
+
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
a
+=
Listeria
spp. were detected in samples; -=
Listeria
spp. were not detected in sample;
b
Confirmed results from OXA and ALOA were identical for each test portion
c
Sample was presumptive positive on VIDAS LMX and confirmed negative,
d
Sample presumptive negative on VIDAS LMX, result was reported positive as
L.seeligeri,
e
Sample was presumptive positive on VIDAS LMX but result was reported positive as
L. welshimeri
f
Result was reported positive as
L. innocua,
g
Result was reported positive as
L. ivanovii,
h
Result was reported positive as
L. grayi,
i
Sample confirmed positive as
L. monocytogenes
j
Results were not used in statistical analysis
16