ABSTRACT
In the food industry, quality, freshness, as well as safety of the products, are major concerns to both consumers and producers. During production of a food material, these parameters are ensured by routine conventional analytic techniques such as chromatography, spectrophotometry, electrophoresis, titration, and microbial analysis, of which some are a part of the Hazard Analysis and Critical Control Points (HACCP) routine. The periodic evaluation of these parameters via chemical and microbial tests is not always suitable for continuous in situ process control and monitoring, for they need sample pretreatment and/or puri‘cation and are expensive and time-consuming. In addition, most of these methods require experienced staff. The
2.1 Introduction .................................................................................................... 53 2.2 Optical Biosensing ..........................................................................................54 2.3 Principles of Optical Detection ...................................................................... 55 2.4 Types of Optical Biosensors ........................................................................... 55
2.4.1 Direct Optical Detection ..................................................................... 55 2.4.1.1 Re—ectometric Detection ..................................................... 55 2.4.1.2 Re—ectometric Interference Spectroscopy ...........................56 2.4.1.3 Ellipsometry ......................................................................... 56 2.4.1.4 Evanescent Field Techniques ...............................................56 2.4.1.5 Mach-Zehnder Interferometer ............................................. 58 2.4.1.6 Young Interferometer ........................................................... 58 2.4.1.7 Resonant Mirror Sensor ....................................................... 59 2.4.1.8 Surface Plasmon Resonance ................................................ 59 2.4.1.9 Grating Couplers .................................................................. 61
2.4.2 Labeled Systems Detection ................................................................. 61 2.4.3 Fiber-Optic Biosensors ....................................................................... 62
2.5 Optical Biosensors for Food Quality and Food Safety ................................... 63 2.6 Conclusion ......................................................................................................66 References ................................................................................................................66
