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Dupont BAX Salmonella Pre- Collaborative Study For Expert Review Panel Use Only Do Not Distribute

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Table 12. BAX® System Presumptive vs. Confirmed Results – Environmentals

95% CI f

dPOD CP e

BAX® Presumptive

BAX® Confirmed

CFU/ sample

Test Portions

Sample Type Media

X b POD CP c

95% CI f

X b POD CC d

95% CI f

Control

5

0 9 5 0 6 5 0

0

(0, 0.43)

0

0

(0, 0.43)

0 0 0 0 0 0 0 0 0 0 0 0

(-0.45, 0.45) (-0.14, 0.14) (-0.45, 0.45) (-0.45, 0.45) (-0.14, 0.14) (-0.45, 0.45) (-0.45, 0.45) (-0.14, 0.14) (-0.45, 0.45) (-0.45, 0.45) (-0.14, 0.14) (-0.45, 0.45)

LB

Ceramic tile

60

20

0.45

(0.26, 0.66) 9

0.45

(0.26, 0.66) (0.57, 1.0)

600

5 5

1.0

(0.57, 1.0)

5 0

1.0

Control

0

(0, 0.43)

0

(0, 0.43)

Ceramic tile

BPW

60

20

0.30

(0.15, 0.52) 6

0.30

(0.15, 0.52) (0.57, 1.0)

600

5 5

1.0

(0.57-1.0)

5 0

1.0

Control

0

(0, 0.43)

0

(0, 0.43)

LB

Plastic

107

20

13

0.65

(0.43, 0.82) 13

0.65

(0.43, 0.82) (0.57, 1.0)

1070

5 5

5 0

1.0

(0.57, 1.0)

5 0

1.0

Control

0

(0, 0.43)

0

(0, 0.43)

Plastic

BPW

107

20

11

0.55

(0.34, 0.74) 11

0.55

(0.34, 0.74) (0.57, 1.0)

1070

5

5

1.0

(0.57, 1.0)

5

1.0

2 3 4 5 6 7 8

b X = Number of positive test portions

c POD CP = Candidate method presumptive positive outcomes divided by the total number of trials d POD CC = Candidate method confirmed positive outcomes divided by the total number of trials

e dPOD CP = Difference between the candidate method presumptive result and candidate method confirmed result POD values f 95% CI = If the confidence interval of a dPOD does not contain zero, then the difference is statistically significant at the 5% level

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