3M MDA2LMO96 Mode D'emploi page 11

In the context of the NF VALIDATION, all samples identified as positive by the 3M Molecular Detection Assay 2 - Listeria
monocytogenes must be confirmed by one of the following tests:
Option 1: Using the ISO 11290
Option 2: Implementing a confirmation method consisting of the following: Transfer 0.1 mL of the Demi-Fraser broth.
Streak directly onto Ottaviani Agosti agar described in ISO 11290
Option 3: Using nucleic acid probes as described in EN ISO 7218
selective agar (see Options 1 or 2).
Option 4: Using any other method certified NF VALIDATION, the principle of which must be different from 3M Molecular
Detection Assay 2 - Listeria monocytogenes. The complete protocol described for this second validated method must be
used. All steps prior to the start of confirmation must be common to both methods.
In the event of discordant results (presumptive positive with the alternative method, non-confirmed by one of the means
described above) the laboratory must follow the necessary steps to ensure the validity of the result obtained.
NOTE: Even a negative sample will not give a zero reading as the system and 3M Molecular Detection Assay 2 - Listeria
monocytogenes amplification reagents have a "background" relative light unit (RLU) reading.
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
Appendix A. Protocol Interruption: Storage and re-testing of heat-treated lysates
1. To store a heat-treated lysate, re-cap the lysis tube with a clean cap (see "Lysis", 4.5)
2. Store at 4 to 8°C for up to 72 hours.
3. Prepare a stored sample for amplification by inverting 2-3 times to mix.
4. Decap the tubes.
5. Place the mixed lysate tubes on 3M Molecular Detection Heat Block Insert and heat at 100 ±1°C for 5 ±1 minutes.
6. Remove the rack of LS tubes from the heating block and allow to cool in the 3M Molecular Detection Chill Block Insert
at least 5 minutes and a maximum of 10 minutes.
7. Continue the protocol at the 'Amplification' section detailed above.
If you have questions about specific applications or procedures, please visit our website at www.3M.com/foodsafety or
contact your local 3M representative or distributor.
References:
1. US Food and Drug Administration Bacteriological Analysis Manual. Chapter 10: Detection and Enumeration of Listeria
monocytogenes in Foods. January 2016 Version.
2. US Department of Agriculture (USDA) FSIS Microbiology Laboratory Guidebook 8.08. Isolation and Identification of
Listeria monocytogenes from Red Meat, Poultry and Egg Products, and Environmental Samples. Effective Date: May 1,
2013.
3. ISO 11290-1. Microbiology of Food and Animal Feeding Stuffs – Horizontal Method for the Detection and Enumeration
of Listeria monocytogenes. Amendment 1, 2004-10-15.
4. ISO/IEC 17025. General requirements for the competence of testing and calibration laboratories.
5. ISO 7218. Microbiology of food and animal feeding stuffs – General rules for microbiological examination.
6. 3M Installation Qualification (IQ) / Operational Qualification (OQ) Protocols and Instructions for 3M Molecular
Detection System.
7. ISO 18593. Microbiology of food and animal feeding stuffs – Horizontal methods for sampling techniques from surfaces
using contact plates and swabs.
8. ISO 6887. Microbiology of food and animal feeding stuffs – Preparation of test samples, initial suspension and decimal
dilutions for microbiological examination.
9. ISO 16140-2. Microbiology of the food chain - Method validation - Part 2: Protocol for the validation of alternative
(proprietary) methods against a reference method.
Explanation of Product Label Samples
www.3M.com/foodsafety/symbols
standard starting from Demi-Fraser enrichment
(3)
.
(3)
standard, performed on isolated colonies, from
(5)
10
(English)
EN