418 / 596
For the low inoculation level of the MDA 2 -
Listeria
assay, there were 11 presumptive positives
1
and 11 confirmed positives following the AOAC 993.12 reference method confirmation
2
procedure. There were 9 observed positives for the reference method. For the high inoculation
3
level, there were 5 presumptive positives and 5 confirmed positives following the AOAC 993.12
4
reference method confirmation procedure. There were 5 confirmed positives following the
5
reference method. Detailed results of the POD analyses are presented in Tables 9 and 13.
6
7
4% Milk fat cottage cheese (25 g)
8
9
For the low inoculation level of the MDA 2 -
Listeria
assay, there were 12 presumptive positives
10
and 12 confirmed positives following the AOAC 993.12 reference method confirmation
11
procedure. There were 9 observed positives for the reference method. For the high inoculation
12
level, there were 5 presumptive positives and 5 confirmed positives following the AOAC 993.12
13
reference method confirmation procedure. There were 5 confirmed positives following the
14
reference method. Detailed results of the POD analyses are presented in Tables 9 and 13.
15
16
17
Beef hot dog (25 g)
18
19
For the low inoculation level of the MDA 2 -
Listeria
assay, there were 4 presumptive positives
20
and 5 confirmed positives following the USDA/FSIS MLG 8.09 reference method confirmation
21
procedure, resulting in 1 false negative. There were 6 observed positives for the reference
22
method. For the high inoculation level, there were 5 presumptive positives and 5 confirmed
23
positives following the USDA/FSIS MLG 8.09 reference method confirmation procedure. There
24
were 5 confirmed positives following the reference method. Detailed results of the POD analyses
25
are presented in Tables 9 and 13.
26
27
28
Stainless steel (sponge enriched in 225 mL)
29
30
Results were identical after 24 and 26 hours of sample enrichment. For the low inoculation level
31
of the MDA 2 -
Listeria
assay, there were 5 presumptive positives and 5 confirmed positives
32
following the USDA/FSIS MLG 8.09 reference method confirmation procedure. There were 8
33
observed positives for the reference method. For the high inoculation level, there were 5
34
presumptive positives and 5 confirmed positives following the USDA/FSIS MLG 8.09 reference
35
method confirmation procedure. There were 5 confirmed positives following the reference
36
method. Detailed results of the POD analyses are presented in Tables 9 and 13.
37
38
39
Sealed concrete (sponge enriched in 100 mL)
40
41
Results were identical after 24 and 26 hours of sample enrichment. For the low inoculation level
42
of the MDA 2 -
Listeria
assay, there were 15 presumptive positives and 15 confirmed positives
43
following the USDA/FSIS MLG 8.09 reference method confirmation procedure. There were 11
44
observed positives for the reference method. For the high inoculation level, there were 5
45
presumptive positives and 5 confirmed positives following the USDA/FSIS MLG 8.09 reference
46