Wiley Handbook of Science and Technology for Homeland Security, 4 Volume Set

MID-INFRARED SENSORS FOR THE RAPID ANALYSIS OF SELECT MICROBIAL FOOD BORNE PATHOGENS

LISA J. MAUER AND BRADLEY L. REUHS

Department of Food Science, Purdue University, West Lafayette, Indiana

1 INTRODUCTION

The goal of sensor research is to provide fast, accurate, and inexpensive methods for detecting chemical and biological contaminants. Sensors based on optical technologies have the advantages of sensor longevity and suitability for continuous monitoring. Optical methods are based on absorption, scattering, or fluorescence of light by the component of interest. Near-infrared (IR) and mid-IR spectroscopy are the most promising of the optical technologies available. IR spectroscopy, on which IR sensors are based, is a form of absorption spectroscopy that can provide both qualitative and quantitative information about the molecules being analyzed. With this method, it is possible to establish the presence of functional groups in a sample and the concentration of the sample components [1]. The measurement of concentration for IR sensors is a one-step relation between the concentration of the component of interest and the detector signal. In IR spectra, any deviation from the baseline (spectra of the control sample) shows the change in the concentration or structure of the component analyzed. Naumann et al. [2, 3] characterized the spectra of bacterial cell into five regions, which were associated with specific chemical groups of the different bacterial components, and concluded that ...