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P2-35 A Comparative Evaluation of the ANSR™ Listeria Assay for the Detection of Listeria Species on Environmental Surfaces

Tuesday, July 30, 2013
Exhibit Hall (Charlotte Convention Center)
Kiel Fisher, Q Laboratories, Inc., Cincinnati, OH
Megan Boyle, Q Laboratories, Inc., Cincinnati, OH
Erin Crowley, Q Laboratories, Inc., Cincinnati, OH
Patrick Bird, Q Laboratories, Inc., Cincinnati, OH
David Goins, Q Laboratories, Inc., Cincinnati, OH
Michael Wendorf, Neogen Corporation, Lansing, MI
Emily Feldpausch, Neogen Corporation, Lansing, MI
Preetha Biswas, Neogen Corporation, Lansing, MI
Mark Mozola, Neogen Corporation, Lansing, MI
Jennifer Rice, Neogen Corporation, Lansing, MI
Introduction: ANSR™ Listeria is an isothermal, amplified nucleic acid assay for detection of Listeria spp. in a variety of food matrices and environmental samples. The method is based on the Nicking Enzyme Amplification Reaction (NEARTM) technology, preceded by reverse transcription of ribosomal RNA. Target cDNA is amplified through a mechanism of polymerization from the ends of nicks created in double-stranded DNA by the action of a specific endonuclease. Amplified target sequences are detected using fluorescent Molecular Beacon®probes.  Amplification and detection require less than 20 minutes. 

Purpose: The purpose of this evaluation was to compare the assay to the USDA/FSIS-MLG 8.07 reference method for detection of Listeria spp. from stainless steel, plastic, ceramic, sealed concrete and rubber environmental surfaces as part of the AOAC Research Institute™ validation process.

Methods: For both the ANSR and reference methods, 20 replicates were analyzed at an inoculation level intended to produce fractional positive results, along with a minimum of 5 high level samples and 5 uninoculated controls.  Following enrichment of samples in ANSR Listeria Enrichment Broth, samples were assayed by the method after 16 and 24 hours of incubation.

Results: Probability of detection (POD) statistical analysis indicated that there were no significant differences between the ANSR and reference methods for the detection of Listeria species on ceramic, sealed concrete, plastic, and rubber surfaces at both 16 and 24 hours.  For stainless steel, the method produced more positive results than the reference method in two internal trials, but results of the two methods were not statistically different in the independent laboratory trial.

Significance: ANSR Listeria is a rapid, reliable alternative method for detection of Listeria spp. in a variety of environmental samples.

Back to: Poster Session 2 - Pathogens, Antimicrobials
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