Fiber-Optic-Based Modular and Handheld Systems

4 Fiber-Optic-Based Modular and Handheld Systems 

Handheld and portable systems may have less resolution and spectral range than laboratory systems but can be customized for specific applications with customized spectral libraries. Specialized applications for these instruments include measuring the freshness of fish by monitoring the concentration of dimethylamine, which is directly related to age and temperature of processed frozen fish (Herrero et al, 2004). Fat concentration, composition, and saturation index allows a handheld Raman instrument to determine in less than 1 min if edible oils such as olive oil have been adulterated or if cheaper oil is being sold as more expensive olive oil. 

Another critical food safety application is the determination of melamine in human and pet food. Melamine has been found in milk and pet food, deliberately added to watered-down or inferior products to boost the apparent protein concentration. The standard wet chemical method for protein in food is the Kjeldahl method, which actually measures nitrogen and is an indirect measure of protein. Melamine responds to the Kjeldahl method just like protein, but is not a protein and is toxic it combines with uric acid to form kidney stones. The USDA has set a maximum allowable limit of 2.5 ppm melamine for adults. Using their portable Nunavut Raman System, BaySpec, Inc., scientists demonstrated the measurement of melamine at levels down to 3 ppm in the field the analysis takes less than 10 s, is accurate, is repeatable, and is nondestructive. 

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