Mutagenicity of chemicals added to foods.

Much attention has recently been brought to the fact that many natural components of the diet are mutagenic and/or carcinogenic. Approximately 2700 distinct chemical entities, chemical mixtures, and plant extracts are allowed as direct food additives by the US F.D.A. These include chemicals found in the body, natural components of foods, and synthetic chemicals. In addition to the chemicals among these additives that are mutagenic, there are a number of mutagens that are normally present in the plant products that are consumed as part of the normal diets. The mutagenicity in Salmonella of these food additives was identified using the National Toxicology Program and US E.P.A. Gene-Tox databases. Relatively few of the chemicals deliberately added to foods have been tested for mutagenicity. Among the chemicals tested, approximately 15% were mutagenic in Salmonella. The mutagens include both organic and inorganic substances. Many of the natural plant components, such as flavonoids, hydrazides, and tannins also have been shown to be mutagenic. However, these natural components are not considered as food additives. A large proportion of the mutagenic food additives appear to act through the generation of oxygen- or free radicals. Although the relationships between mutagenicity and carcinogenicity of electrophilic chemicals has been well studied, the potential hazard of low-level increases in free-radical generating substances on tumor incidences is unknown.