341 / 363
C
rowley
et al
.:
J
ournal of
AOAC I
nternational
V
ol
.
97, N
o
. 2, 2014
439
portions confirmed positive. For the uninoculated controls, 0
out of 144 test portions confirmed positive.
For the low-level inoculum, dLPOD
C
values of 0.01
(–0.10, 0.13) were obtained between AOAC
993.12
and VIDAS
LPT. The confidence intervals obtained for dLPOD
C
indicated
no significant difference between the two methods. dLPOD
CP
values of 0.00 (–0.12, 0.12) were obtained between presumptive
and confirmed VIDAS LPT results. The confidence intervals
obtained for dLPOD
CP
indicated no significant difference
between the presumptive and confirmed results using either
confirmation process.
For the high-level inoculum, dLPOD
C
values of 0.00
(–0.03, 0.03) were obtained between AOAC
993.12
and VIDAS
LPT. The confidence intervals obtained for dLPOD
C
indicated
no significant difference between the two methods. dLPOD
CP
values of 0.00
(–0.03, 0.03) were obtained between presumptive
and confirmed VIDAS LPT results. The confidence intervals
obtained for dLPOD
CP
indicated no significant difference
between the presumptive and confirmed results. Detailed results
of the POD statistical analysis are presented in Table
2013.10B
,
as supplemental data on the
J. AOAC Int.
website, Tables 2C–D,
and Figures
2
A–D.
ALOA Chromogenic Agar
Confirmatory results obtained from the ALOA chromogenic
Table 3. Individual collaborator results for queso fresco
a
(25 g test portions)
VIDAS LPT
b
High-level test portions
Low-level test portions
Uninoculated test portions
Lab 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
1 + + + + + + + + + + + + + + + – – – – + – + – + – – – – – – – – – – – –
2 + + + + + + + + + + + + + – + – – – – + – – – + – – – – – – – – – – – –
3 + + + + + + + + + + + + – – + + – + – – – + – – – – – – – – – – – – – –
4 + + + + + + + + + + + + + – + + + – + – – + + – – – – – – – – – – – – –
5 + + + + + + + + + + + + + – + – – + + – – – – + – – – – – – – – – – – –
6 + + + + + + + + + + + + + – – – – + – + + – + + – – – – – – – – – – – –
7 + + + + + + + + + + + + – – + + – – – + – + + + – – – – – – – – – – – –
8 + + + + + + + + + + + + + + – + – – + + + + – + – – – – – – – – – – – –
9 + + + + + + + + + + + + + + – + – + – – + – + + – – – – – – – – – – – –
10 + + + + + + + + + + + + – – – + + – – + – + + + – – – – – – – – – – – –
11
c
+ + + + + + + + + + + + – – – + + – – + – + + + – – – – – – – – – – – –
12 + + + + + + + + + + + + + – – – + – + + + + + – – – – – – – – – – – – –
13 + + + + + + + + + + + + – – – + + – + + + – + + – – – – – – – – – – – –
14 + + + + + + + + + + + + – + – + + – – – + + –
d
–
d
– – – – – – – – – –
d
– –
AOAC
993.12
1 + + + + + + + + + + + + – + – + + + – – + – – – – – – – – – – – – – – –
2 + + + + + + + + + + + + + + + + – + – – – – – – – – – – – – – – – – – –
3 + + + + + + + + + + + + + – + + + – – + + – – – – – – – – – – – – – – –
4 + + + + + + + + + + + + + + – + + – – – + – + + – – – – – – – – – – – –
5 + + + + + + + + + + + + + + + – + – – – – – – – – – – – – – – – – – – –
6 + + + + + + + + + + + + – – – – – + + + + – + + – – – – – – – – – – – –
7 + + + + + + + + + + + + – – – – + + – + + + + + – – – – – – – – – – – –
8 + + + + + + + + + + + + – – – – – – + + + + + + – – – – – – – – – – – –
9 + + + + + + + + + + + + – – – – + + – + + + + + – – – – – – – – – – – –
10 + + + + + + + + + + + + – – + + – – + – + – + + – – – – – – – – – – – –
11
c
+ + + + + + + + + + + + – +
e
+ + + + – – + – + + +
e
+
e
+
e
– – – +
e
+
e
– – +
e
+
c
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
Results were not used in statistical analysis.
d
Sample was presumptive positive on VIDAS LPT but confirmed negative indicating a false-positive result.
e
Result reported as
L. grayi
(doubtful API Profile).
Candidates for 2016 Method of the Year
340