634-635 / 1195
Table 8 continued.
Probability of Detection Results – VIDAS LPT Presumptive vs. Confirmed
1
2
Matrix
Strain
MPN
a
/test portion
N
c
LPT Presumptive
LPT Confirmed
dPOD
CP
g
95% CI
h
x
d
POD
CP
e
POD
CC
f
95% CI
Black
pepper
-25g-
L. innocua
ATCC 33090
control
5
0
0
0.00, 0.43
0
0
0.00, 0.43
0
-0.43, 0.43
0.79
20
8
0.40
0.21-0.61
8
0.40
0.21-0.61
0
-0.28, 0.28
Vanilla ice
cream
-25g-
L. ivanovii
ATCC 13124
control
5
0
0
0.00, 0.43
0
0
0.00, 0.43
0
-0.43, 0.43
1.31
20
18
0.90
0.70-0.97
18
0.90
0.70-0.97
0
-0.21, 0.21
Soft cheese
(fresh
queso)
-25g-
L. monocytogenes
ATCC 19114
control
5
0
0
0.00, 0.43
0
0
0.00, 0.43
0
-0.43, 0.43
0.79
20
9
0.45
0.26-0.66
9
0.45
0.26-0.66
0
-0.28, 0.28
Soft cheese
(fresh
queso)
-125g-
L. monocytogenes
ATCC 19114
control
5
0
0
0.00, 0.43
0
0
0.00, 0.43
0
-0.43, 0.43
0.79
20
11
0.55
0.34-0.74
11
0.55
0.34-0.74
0
-0.28, 0.28
Matrix
Strain
Inoculum Level
Added per 100 cm
2
N
c
LPT Presumptive
LPT Confirmed
dPOD
CP
g
95% CI
h
x
d
POD
CP
e
95% CI
x
POD
CC
f
95% CI
Ceramic
L .innocua
ATCC
a
33090
Plus competitor
control
5
0
0
0.00, 0.43
0
0
0.00, 0.43
0
-0.43, 0.43
1.8 x 10
4
20
6
0.30
0.15, 0.52
6
0.30
0.15, 0.52
0
-0.27, 0.27
Stainless
steel
L.monocytogenes
Plus competitor
control
5
0
0
0.00, 0.43
0
0
0.00, 0.43
0
-0.43, 0.43
1.3 x 10
2
20
11
0.55
0.34, 0.74
10
0.50
0.30, 0.70
0.05
-0.24, 0.33
Plastic
L.welshimeri
ATCC 35897
control
5
0
0
0.00, 0.43
0
0
0.00, 0.43
0
-0.43, 0.43
1.6 x 10
5
20
18
0.90
0.70, 0.97
18
0.90
0.70, 0.97
0
-0.21, 0.21
Concrete
L.monocytogenes
NCTC 11994
Plus competitor
control
5
0
0
0.00, 0.43
0
0
0.00, 0.43
0
-0.43, 0.43
8.7 x 10
2
20
14
0.70
0.48, 0.85
14
0.70
0.48, 0.85
0
-0.27, 0.27
a
MPN = Most Probable Number is based on the POD of reference method test portions across labs using the AOAC MPN calculator, with 95% confidence interval
3
b
N = Number of test potions
4
c
x = Number of positive test portions
5
d
POD
CP
=
Candidate method presumptive positive outcomes divided by the total number of trials
6
e
POD
CC
= Candidate method confirmed positive outcomes divided by the total number of trials
7
f
dPOD
CP
= Difference between the candidate method presumptive result and candidate method confirmed result POD values
8
g
95% CI = If the confidence interval of a dPOD does not contain zero, then the difference is statistically significant at the 5% level
9