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Comparative Evaluation of the VIDAS®
Listeria
monocytogenes Express (LMX) for the Detection of
Listeria monocytogenes
in a
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variety of foods: AOAC
Performance Tested Method
SM
MMYYNN
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Abstract
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The VIDAS®
Listeria
monocytogenes
Xpress (LMX) test is an enzyme-linked fluorescent immunoassay (ELFA) designed for use
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with the automated VIDAS® or mini-VIDAS® instruments for the specific detection of
Listeria
monocytogenes
using a 26-hour
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proprietary enrichment broth. The VIDAS LMX method was validated according to harmonized AOAC Research Institute (RI) and
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Official Method of Analysis (OMA) guidelines in both the AOAC The
Performance Tested Method
SM
(PTM) and GovVal programs.
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In the PTM comparison studies, the VIDAS LMX method was compared to the USDA/FSIS MLG, FDA-BAM and AOAC Official
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Methods. The comparative food studies consisted of two main parts: internal testing and AOAC independent laboratory testing, which
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included seven food matrices (deli-ham, processed cheese, vanilla ice cream, cooked shrimp, smoked white fish, frozen spinach and
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peanut butter). As part of the AOAC® Research Institute GovVal program, the VIDAS LMX method was compared to the Health
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Canada MFHPB-30 method for the detection of
Listeria monocytogenes
in five “ready to eat” (RTE) meats (hot dogs, deli turkey, deli
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ham, fermented sausage, and liver paté). Twenty replicates of each inoculation level and five uninoculated controls were evaluated in
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each study. The LSX method also included the use of chromogenic media, chromIDTM Ottaviani Agosti Agar (OAA) and
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chromIDTM Lmono, for confirmation of LMX presumptive results.
In both the PTM and GovVal evaluations there were no
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significant differences in the chi-square values for the LMX method when compared to reference methods. The additional parameters
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tested in the PTM evaluation (inclusivity, exclusivity, ruggedness, stability, and lot-to-lot) satisfied the AOAC RI performance
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requirements. In both the PTM and GovVal validation studies the VIDAS LMX method demonstrated reliability as a rapid qualitative
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method for the next day detection of
Listeria monocytogenes
in a variety of foods including RTE meats.
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Method Authors
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Ron Johnson and John Mills
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bioMérieux, Inc.
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595 Anglum Drive
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Hazelwood, MO 63042
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USA
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Jean-Louis Pittet
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BioMerieux SA
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Chemin de l'Orme,
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69280 Marcy l'Etoile
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France
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PTM Certification Report