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Table 11. BAX® System vs. Reference Method Results – Dairy Products
Sample Type
Media
MPN
a
Test
Portions
BAX® Method
Reference Method
dPOD
C
e
95% CI
f
X
b
POD
C
c
95% CI
f
X
b
POD
CC
d
95% CI
f
Nonfat dry milk (25 g)
Brilliant Green
Water / BHI
Control
5
0
0
(0, 0.43)
0
0
(0, 0.43)
0
(-0.45, 0.45)
1.2 (0.79, 1.8)
20
11
0.55
(0.34, 0.74) 11
0.55
(0.34, 0.74)
0
(-0.14, 0.14)
9.4 (5.7, 16)
5
5
1.0
(0.57, 1.0)
5
1.0
(0.57, 1.0)
0
(-0.45, 0.45)
Ice cream (25 g)
LB
Control
5
0
0
(0, 0.43)
0
0
(0, 0.43)
0
(-0.45, 0.45)
0.31 (0.17, 0.49)
20
9
0.45
(0.26, 0.66)
6
0.30
(0.15, 0.52)
0.15
(-0.14, 0.41)
1.8 (1.1, 2.7)
5
3
0.60
(0.23, 0.88)
4
0.80
(0.38, 1.0)
-0.20
(-0.62, 0.27)
Ice cream (25 g)
BPW
Control
5
0
0
(0, 0.43)
0
0
(0, 0.43)
0
(-0.45, 0.45)
0.31 (0.17, 0.49)
20
6
0.30
(0.15, 0.52)
6
0.30
(0.15, 0.52)
0
(-0.14, 0.14)
1.8 (1.1, 2.7)
5
4
0.80
(0.38, 1.0)
4
0.80
(0.38, 1.0)
0
(-0.45, 0.45)
Ice cream (25 g)
Brilliant Green
Water
Control
5
0
0
(0, 0.43)
0
0
(0, 0.43)
0
(-0.45, 0.45)
0.31 (0.17, 0.49)
20
6
0.30
(0.15, 0.52)
6
0.30
(0.15, 0.52)
0
(-0.27, 0.27)
1.8 (1.1, 2.7)
5
5
1.0
(0.57, 1.0)
4
0.80
(0.38, 1.0)
0.20
(-0.27, 0.62)
a
MPN = Most Probable Number based on the POD of reference method test portions using the AOAC MPN calculator (with 95% confidence interval)
2
b
X = Number of positive test portions
3
c
POD
C
=
Confirmed candidate method positive outcomes divided by the total number of trials
4
d
POD
R
= Confirmed reference method positive outcomes divided by the total number of trials
5
e
dPOD
C
= Difference between the candidate method and reference method POD values
6
f
95% CI = If the confidence interval of a dPOD does not contain zero, then the difference is statistically significant at the 5% level
7
8
9
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