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P2-33 Development and Application of a Rapid Lateral Flow Test Strip-based Method for the Detection of Listeria monocytogenes in Food

Tuesday, July 30, 2013
Exhibit Hall (Charlotte Convention Center)
Mark Muldoon, Romer Lab Technologies, Inc., Newark, DE
Verapaz Gonzalez, Romer Lab Technologies, Inc., Newark, DE
Ann-Christine Allen, Romer Lab Technologies, Inc., Newark, DE
Zheng Jiang, Romer Lab Technologies, Inc., Newark, DE
Meredith Sutzko, Romer Lab Technologies, Inc., Newark, DE
Introduction: Listeria monocytogenes is the causative agent of listeriosis.  The CDC estimates that 1,662 cases of listeriosis occur annually in the US, resulting in 1,520 hospitalizations and 266 deaths.  USDA-FSIS monitoring programs at food processing establishments test ready-to-eat (RTE) foods and food contact surfaces for L. monocytogenes.  Cultural methods require up to 3 days for results to be obtained while rapid instrument-based methods are less than 2 days.   In order to simplify rapid testing, we have developed a test strip-based method for the detection of L. monocytogenes in food.  

Purpose: The purpose of this study was to develop a new test strip-based method for the detection of L. monocytogenes in food. 

Methods: Monoclonal antibodies (39) were screened against L. monocytogenes and L. innocua by sandwich ELISA (1521 combinations).  Antibody pairs that gave the best specificity and sensitivity (84) were further pursued in the test strip format. Inclusivity/exclusivity studies evaluated 50 Listeria spp. strains, including 30 L. monocytogenes strains, and 35 non-Listeria bacterial strains.  One test strip design was coupled to a 40 h enrichment and compared to the USDA-FSIS cultural reference method for the detection of L. monocytogenes in 125 g hot dog samples. 

Results: The new method demonstrated 100% sensitivity and 100% specificity for L. monocytogenes.  Out of 20 inoculated samples, the number of positive results reported for the new L. monocytogenes test strip method was 16 and the USDA-FSIS method was 19.  The number of positive results obtained with the L. monocytogenes test strip method was equivalent to the number obtained with the USDA-FSIS method (X2 = 2.01) for the detection of L. monocytogenes in 125 g hot dog samples.

Significance: The new test strip method should provide the food industry with a rapid and reliable diagnostic tool for monitoring and preventing L. monocytogenes contamination of food.

Back to: Poster Session 2 - Pathogens, Antimicrobials
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