"The ability of biosensors to detect the presence of pathogens or toxins is critical to ensure product safety."

Optical biosensors for food pathogen detection

Investigator: Arun K. Bhunia (Department of Food Science)

Project Report 2007 - 2008

» Download Project Report 2007 - 2008

Project Rationale

The ability of biosensors to detect the presence of pathogens or toxins is critical to ensure product safety. Biosensors employing specific antibodies are being widely used and shown to be effective. Our goal was to develop a fiber optic sensor using antibodies for detecting foodborne pathogens, including Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Enteritidis. We developed a fiber optic sensor for L. monocytogenes and E. coli O157:H7. We also developed a sensitive and specific fiber optic detection assay for S. Enteritidis in poultry. The assay was compared to time-resolved immunofluorescence (TRF) for confirmation. An efficient multi-pathogen array using a flow-through immobilization protocol was also developed for detecting L. monocytogenes, E .coli, and S. Enteritidis. Pilot studies are underway to analyze the binding efficiencies of an antibody-pathogen complex using selected surface chemistries in order to gain a better understanding of the molecular nature of these interactions. This approach will enable us to increase sensitivity and specificity of binding on the sensor.

Project Objectives

  • Develop and evaluate an antibody-coupled fiber optic biosensor [ANALYTE 2000™] for detecting S. Enteritidis.
  • Develop an efficient multi-pathogen array using a fiber optic biosensor. This requires screening and identifying monoclonal and polyclonal antibodies, developed in our laboratory, for L. monocytogenes, E. coli O157:H7, and S. Enteritidis, and developing efficient surface chemistry protocols for evaluating and quantifying the binding interactions of an antibody-pathogen complex on the surface of a fiber optic sensor.

Project Highlights

We obtained the antibodies required to detect multiple pathogens using a fiber optic sensor. The antibodies were labeled with fluorophor (Alexa-Fluor) and thoroughly characterized according to their reaction patterns to target pathogens when grown on a multi-pathogen selective enrichment broth, SEL (Salmonella, E. coli, and Listeria). Initial experimental trials indicate that we can detect these three pathogens simultaneously using a fiber optic sensor. Cross-reactions with heterologous bacteria were minimal.