Antibody Immobilization on Waveguides Using aFlow–Through System Shows Improved Listeria monocytogenesDetection in an Automated Fiber Optic Biosensor: RAPTORTM

Arun Bhunia,Tao Geng,Angela Valadez,Giyoung Kim,Aparna Kothapalli,Byoung-Kwon Hahm,Mark Morgan,Daniel Ess,Viswaprakash Nanduri

doi:10.3390/s6080808

Abstract

Recent outbreaks of food borne illnesses continue to support the need for rapidand sensitive methods for detection of foodborne pathogens. A method for detecting Listeriamonocytogenes in food samples was developed using an automated fiber-optic-basedimmunosensor, RAPTORTM. Detection of L. monocytogenes in phosphate buffered saline(PBS) was performed to evaluate both static and flow through antibody immobilizationmethods for capture antibodies in a sandwich assay. Subsequent detection in frankfurtersamples was conducted using a flow through immobilization system. A two stage blockingusing biotinylated bovine serum albumin (b-BSA) and BSA was effectively employed toreduce the non-specific binding. The sandwich assay using static or flow through mode ofantibody immobilization could detect 1

Highlights

Listeria monocytogenes is one of the major foodborne pathogens and current U.S regulatory policy maintains a “zero tolerance” in ready-to-eat (RTE) foods
A recent risk assessment study estimated the risks of serious illness and death associated with consumption of RTE foods possibly contaminated with L. monocytogenes
A recent risk assessment study conducted by Food and Agriculture Organization (FAO) and the World Health Organization (WHO) indicated that the readyto-eat products are of highest risk for L. monocytogenes and the risk increases with increase dose at the time of consumption [2]

Summary

Introduction

Listeria monocytogenes is one of the major foodborne pathogens and current U.S regulatory policy maintains a “zero tolerance” in ready-to-eat (RTE) foods. It is a gram-positive, rod-shaped intracellular pathogen that causes listeriosis in elderly, those with weakened immune systems, and pregnant women. A recent risk assessment study estimated the risks of serious illness and death associated with consumption of RTE foods possibly contaminated with L. monocytogenes. A recent risk assessment study conducted by Food and Agriculture Organization (FAO) and the World Health Organization (WHO) indicated that the readyto-eat products are of highest risk for L. monocytogenes and the risk increases with increase dose at the time of consumption [2]

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Results