Table of Contents Table of Contents
Previous Page  175 / 596 Next Page
Information
Show Menu
Previous Page 175 / 596 Next Page
Page Background

1

Results were identical after 24 and 26 hours of sample enrichment. For the low inoculation level

2

of the MDA 2 -

Listeria

assay, there were 15 presumptive positives and 15 confirmed positives

3

following the USDA/FSIS MLG 8.09 reference method confirmation procedure. There were 11

4

observed positives for the reference method. For the high inoculation level, there were 5

5

presumptive positives and 5 confirmed positives following the USDA/FSIS MLG 8.09 reference

6

method confirmation procedure. There were 5 confirmed positives following the reference

7

method. Detailed results of the POD analyses are presented in Tables 9 and 13.

8

9

10

Product Consistency (Lot-to-Lot) and Stability Studies

11

12

Methodology

13

Three lots of MDA 2 -

Listeria

test kits, 1 newly manufactured, 1 at the middle of its expiration,

14

and 1 at or slightly beyond expiration were analyzed to determine the stability of the assay. For

15

the MDA 2 -

Listeria

test kit, one

Listeria monocytogenes

ATCC 7644 isolate was analyzed at a

16

fractional positive level (2-8 positives), and testing 10 replicates. One non-

Listeria

isolate,

17

Enterococcus faecalis

ATCC 29212, was analyzed at the growth level achieved in a non-

18

selective broth, testing 5 replicates.

19

20

Results

21

For the lot-to-lot/stability evaluation of the MDA 2 -

Listeria

assay, there were 6 presumptive

22

positives out of 10 replicates for all three lots at the low inoculation level. For the 5 uninoculated

23

control test portions, there were 0 presumptive positives out of 5 replicates for all three lots. The

24

five control test portions were negative. See Table 16 for lot-to-lot/stability results.

25

26

Robustness Study

27

28

Methodology

29

The robustness evaluated the ability of the method to remain unaffected by minor variations in

30

method parameters that might be expected to occur when the method is performed by an end

31

user. Three different parameters were evaluated, which are presented in Table 18. For each

32

parameter, one

Listeria monocytogenes

ATCC 7644

isolate was analyzed at a fractional positive

33

level (2-8 positives), testing 10 replicates. One non-

Listeria

isolate,

Enterococcus faecalis

ATCC

34

29212, was analyzed at the growth level achieved in a non-selective broth, testing 5 replicates.

35

36

Table B: Robustness Parameters

37

38

Parameter

Low Value

Nominal Value

High Value

Lysis Time

13 minutes

15 minutes

17 minutes

Enrichment Volume

18 µL

20 µL

22 µL

Lysate Volume

18 µL

20 µL

22 µL

39

Table C: Robustness Parameter Variations

40

41

Treatment

Lysis Time

Volume

Volume

# of Replicates

AOAC Research Institute

Expert Review Panel Use Only

OMAMAN-29 D/ PTM Validation Report 111501

OMA ERP - June 2016

ERP Use Only