Techniques of food inspection

The final message I will introduce chromatographic techniques. Chromatography is a technique of great importance in the field of separation science. Chromatography is a common name for techniques based on the adsorption and/or partition of molecules to be separated between a mobile and a stationary phase. Separation is the result of selective distribution of molecules between the two phases. Chromatographic techniques are one of the more active areas in food analysis. Methods most frequently used in food analysis are HPLC and GC. Becauseof their high separation capacity, chromatographic procedures have found increasing employment in food science for the qualitative and quantitative analysis of a large number of molecules such as normal constituents of foods.

Authenticity of vegetable oils has become an important issue since oils and fats constitute one of the major classes of food products. Among those previously mentioned, olive oil is the most studied. A wide variety of methods has been developed to confirm the authenticity or detect the adulteration of olive oils. Fat and oil authentication by means of the analysis of different component lipid classes by both HPLC and GC analysis can facilitate detection of their adulteration. The percentage values for each fatty acid are compared with those recognized by national and international organizations, and increases or decreases in the levels of certain fatty acids may indicate adulteration. Another case is milk.

As is the case with vegetable oils, detection of adulteration by the substitution of one milk type for another has been achieved by protein analysis. HPLC analysis has been employed to determine individual milk proteins due to the fact that different chromatographic profiles are obtained for milk from different species.