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Table 5. Variables in ruggedness study
Variable
Normal level Low level
High level
1) Sample volume lysed
5 µL
4 µL
6 µL
2) Incubation temperature (lysate)
37ºC
30ºC
44ºC
3) Incubation time (lysate)
20 minutes
18 minutes 22 minutes
4) Inactivation temperature
95ºC
92ºC
98ºC
5) Inactivation time
10 minutes
8 minutes
12 minutes
6) Total hydration volume
30 µL
24 µL
36 µL
7) Incubation temperature (enrichment)
41 ºC
31 ºC
44 ºC
The ruggedness factors were tested at both high and low levels with five replicates of two
557
Salmonella
strains (DD1261,
S
. Newport and DD1333
S
. Agona) and one non-
Salmonella
558
(DD8990
C. freundii
). Two un-inoculated samples will be tested at each level.
559
Results and Discussion –
The results of the ruggedness study are shown in Table 8. All
560
Salmonella
inoculated samples returned positive results. All non-
Salmonella
inoculated and un-
561
inoculated samples were negative. These results indicate that the variables studied did not
562
affect the performance of the BAX® System assay within the ranges tested.
563
564
Table 6. Results of ruggedness study
Variable
Normal
level
Pos -
Salmonella
Pos
Non-
Salmonella
Pos
Uninoc.
Low
level
Positive
Salmonella
Positive
Non-
Salmonella
Positive
Uninoc.
High
level
Positive
Salmonella
Positive
Non-
Salmonella
Positive
Uninoc.
1) Sample
volume lysed
20 µL
10/10
0/5
0/2
16 µL
10/10
0/10
0/2
24 µL
10/10
0/10
0/2
2) Incubation
temperature - lysis
37ºC
10/10
0/5
0/2
33ºC
10/10
0/10
0/2
41ºC
10/10
0/10
0/2
3) Incubation
time - lysis
20 min
10/10
0/5
0/2
18 min
10/10
0/10
0/2
22 min
10/10
0/10
0/2
4) Inactivation
temperature
95ºC
10/10
0/5
0/2
92ºC
10/10
0/10
0/2
98ºC
10/10
0/10
0/2
5) Inactivation
time
10 min
10/10
0/5
0/2
8 min
10/10
0/10
0/2
12 min
10/10
0/10
0/2
6) Total hydration
volume
30 µL
10/10
0/5
0/2
24 µL
10/10
0/10
0/2
36 µL
10/10
0/10
0/2
7) Incubation
temperature
(enrichment)
41 ºC
10/10
0/5
0/2
31 ºC
10/10
0/10
0/2
44 ºC
10/10
0/10
0/2
565
Dupont BAX Salmonella PTM Report
PTM Certification No. 081201 (08/07/2012)
For Expert Review Panel Use Only
Do Not Distribute