Natural non-nutrient substances in the food chain

Abstract

The toxic potential of a limited number of mycotoxins, biologically active natural products and trace elements has been reviewed from a primary focus of selection as to their contamination of the food supply whether by direct consumption or via domestic animals used for milk production or meat consumption. An assessment of potential toxicants requires knowledge of the chemical form of the contaminant as well as its origin. In addition to contamination of food, air, water and soil are the other routes that must be considered when assessing what part of the total human bond of a given contaminant is due to a specific source. Additional focus has given in this review to environmental agents which are teratogenic, mutagenic and/or carcinogenic although it is recognized that there have been few reports cited to establish the interrelationship of teratogenesis, oncogenesis, mutagenesis, and chromosome damage and the subcellular or molecular basis for these abnormalities may be obscure and unrelated. However, this does not preclude the necessity of drawing attention to the possible or potential toxic nature of the agents discussed. Although trace metals such as selenium, lead, arsenic and cadmium have been shown to be carcinogenic in experimental animals, to date there appears to be no epidemiological evidence that oral ingestion of these metals in the average amounts in which they are normally found, is associated with a carcinogenic hazard in man. It must also be emphasized that although several epidemiological surveys in such regions as Africa, Southeast Asia, India and Japan have contributed important presumptive evidence in regard to liver and gastrointestinal neoplasia, the difficulty of unequivocally ascribing a definitive etiological agent is realized when one considers the myriad aspects of the presence and concentration of various food contaminants, e.g. pesticides, mycotoxins, plant and seed toxicants, radionuclides, trace metals and processing degradation products. an added problem arises in regard to the difficulty of focusing on specific food items consumed rather than on the basis of general classification such as meats, fruits, cereal products or vegetables. The etiology of a disease may also be dependent upon one or more foods, as well as genetic and previous environmental interrelationships. The possibility of potentiation or synergism in regard to hazards presented by foodstuffs contaminated by several toxin-producing molds or by several mycotoxins must also be considered.