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VIDAS LMX & LPT Collaborative Study
April 19, 2013
OMA-2013-Apr-XXX
There was no significant difference between the VIDAS LMX assay and the
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reference method for any of the matrices tested using the Mantel-Haenszel Chi-
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square test at 5% level with the exception of hot dogs (8.27) where the VIDAS
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method resulted in more positives than the reference method. There was one false
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negative result out of a total of 213 positive test portions.
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All other PTM parameters (inclusivity, exclusivity, ruggedness, stability and lot to
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lot) showed expected results. The method was awarded PTM certification
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number 091103 on September 14, 2011.
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A matrix extension to the current PTM certificate (091103) was granted on
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January 15, 2013 for the following matrices (125g): ground beef, queso fresco,
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deli ham, deli turkey.
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1.4
Summary of the LPT Precollaborative Study
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The VIDAS LPT method was evaluated according to AOAC Guidelines (2002) in
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a precollaborative study. The aim of this study was to demonstrate that the
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VIDAS LPT method could detect
Listeria
spp. in a variety of foods as claimed by
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the manufacturer.
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There were 11 foods tested using 25g test portions sizes, two foods tested using
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125g test portion sizes, two foods tested using both 25g and 125g test portions
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sizes, and four environmental surfaces compared to the appropriate reference
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method: USDA/FSIS MLG, 25g (deli ham, pepperoni, beef hot dogs, chicken
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nuggets, chicken liver paté); USDA/FSIS MLG, 125g (deli ham, ground beef, deli
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turkey); FDA-BAM, 25g (cooked shrimp, smoked salmon, cantaloupe melon,
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bagged mixed salad, regular peanut butter, black pepper); AOAC, 25g (vanilla ice
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cream, queso cheese); AOAC, 125g (queso cheese) and USDA/FSIS MLG,
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environmental surfaces (plastic, stainless steel, ceramic and concrete).
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The inclusivity and exclusivity evaluation data showed no unexpected results.
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The VIDAS LPT method detected all of the
Listeria
strains tested and none of the
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non-
Listeria
strains tested. For the method comparison study, there were no
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significant differences between the LPT method and the reference method for
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detection of
Listeria
for the majority of the foods and surfaces tested using the
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unpaired chi-square test at 5% level and the POD analysis. There were three
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matrices where there was a significant difference (hot dogs, mixed salad and
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stainless steel) with the LPT method showing significantly better recovery. There
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was one false positive result out of the 420 low level samples tested by the LPT
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method.
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1.5
Study Director for Collaborative Study
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The co-Study Directors for this collaborative study:
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DRAFT DOCUMENT
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