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3M MDA 2
Listeria
species and
L. monocytogenes
Collaborative Study
OMA-2016-MONTH-XXX
5/4/16
4.6.1.2
Raw chicken breast
- aseptically add the 25g test portion to 475
mL Demi Fraser broth.
4.6.1.2.1
Homogenize thoroughly in a filter bag for 2 ± 0.2 min
4.6.1.2.2
Incubate 28-32 hr at 37 ± 1°C.
4.6.2
Prepare the 3M Molecular Detection speed loader tray, chill block insert,
heat block insert and instrument. Equilibrate the LS tubes to room
temperature (20-25 ºC) by setting LS tube overnight 16-18 hours. Or on
the laboratory bench for at least 2 hours.
4.6.3
Invert the capped LS tubes to mix, up to 4 hours before use.
4.6.4
Transfer 20 µL enriched sample into a LS tube.
4.6.5
Transfer 20 µL Negative Control [NC], sterile enrichment medium (e.g.
Demi-Fraser Broth) into a Lysis Solution [LS] tube after all enriched
samples have been completed. Do not use water as a NC.
4.6.6
Place uncovered LS tubes in 3M Molecular detection Heat block, heat
15±1 min at 100±1°C. LS Solution will change from pink (cool) to yellow
(hot).
4.6.7
Place LS tubes (without rack lid) in chill block insert (at ambient
temperature) for 5-10 min. Lysis solution in LS tube will revert to pink
color.
4.6.8
Transfer 20 µL sample lysate from the upper portion of fluid in the LS
tube into regent tube. Mix gently by pipetting up and down 5 times.
4.6.9
Transfer 20 µL of NC lysate into a reagent tube.
4.6.10
Transfer 20 µL of NC lysate into a Reagent Control (RC) tube.
4.6.11
When all samples have been transferred, load capped tubes into speed
loader tray and close lid.
4.6.12
Start assay.
4.6.13
Results and Interpretation - An algorithm interprets the light output curve
resulting from the detection of the nucleic acid amplification. Results are
analyzed automatically by the software and are color-coded based on the
result. A Positive or Negative result is determined by analysis of a number
of unique curve parameters. Presumptive positive results are reported in
real-time while Negative and Inspect results will be displayed after the run
is completed. Presumptive positive results should be confirmed using your
preferred method or as specified by local regulations.
NOTE:
Even a negative sample will not give a zero reading as the
3M MDS and 3M MDA amplification reagents have a “background”
relative light unit (RLU).
In the rare event of any unusual light output, the algorithm labels this
as “Inspect.” 3M recommends the user to repeat the assay for any
Inspect samples. If the result continues to be Inspect, proceed to
confirmation test using your preferred method or as specified by local
regulations.
AOAC Research Institute
Exp rt Review Panel Use Only
OMAMAN-29/OMAMAN-30 Combined Collaborative Study Protocol
OMA ERP - June 2016
ERP Use Only