Coloring agents, additives permitted

The types of additives discussed here lead to important physical changes. Thus blowing agent use permits the production of cellular structures flame retardants improve thermal and combustion characteristics pigments and colorants change the aesthetic aspect while physical and mechanical properties are modified by active fillers and reinforcements. 

The U.S. Food and Drug Administration (FDA) regulates the addition of nitrate and nitrite salts to fish products. Maximum permitted levels vary among products and types of fish, with up to 500 ppm residual sodium nitrate or 200 ppm sodium nitrite permitted as a preservative and color fixative in smoke cured sable fish, shad, or salmon (Code of Federal Regulations, 1981a,b Committee on Nittite and Alternative Curing Agents in Food, 1981). 

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