Nutritional Quality Control of Foods and Feedstuffs

Food and feed quality begins with the selection of the best-quality ingredients, which are evaluated in terms of physical properties that include color, smell, taste, and texture, and proximate and chemical analyses that include amino acids, fatty acids, minerals, and vitamins. The amino acid profile is usually determined by ion-exchange chromatography or HPLC systems equipped with fluorescent detectors. The fatty acid composition is, in most instances, analyzed via gas chromatography coupled with a flame ionization detector. New capillary columns allow the analysis of fatty acid isomers, such as trans configured, that need to be declared in food labels in many countries around the globe. 

Minerals are usually analyzed by the traditional method of atomic absorption spectroscopy or with the newer induced coupled plasma analyzers. Most vitamins are analyzed by HPLC systems or colorimetric assays. Many laboratories still quantify folic acid with the use of a microbiological assay. The analysis of dietary and detergent (neutral and acid) fibers are critically important for foods and feeds, respectively. Raw materials and feeds should be examined for rodent contamination, pathogenic bacteria, molds and mycotoxins, and undesirable toxicants such as PCB, insecticides, herbicides, and heavy metals. The proper selection of ingredients will ensure the production of high-quality foods that satisfy sensory properties required for humans, and feeds that are palatable and can meet sensory properties required for domestic animals (Chapter 18). 

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