Decision on the control of a dietary carcinogen -- aflatoxin.

The sequence of events is described whereby decisions are made by the scientific community and national or international legislative bodies in evaluating a dietary carcinogen. This is proposed on the basis of experience gained from the aflatoxins. Suspicion arose first after the deaths of large numbers of poultry and fish; the agent was soon identified as aflatoxins. This was followed by laboratory investigations of their toxic and carcinogenic effects in experimental animals, which showed them to be the most potent liver carcinogen known to experimentalists. Field studies were established to assess a possible association with liver-cell cancer in humans, and a significant correlation was found. An intervention programme was therefore set up to lower exposure and to observe the trend of cancer incidence. Aflatoxins are found in many cereals and nuts exposed to humidity; thus, the staple foods of most of the developing world are at risk. The severity of the economic problem for some countries if prejudice should continue to develop against peanuts as a basis for animal feeds is illustrated. Decisions about control of aflatoxins thus fall into two groups: control measures to prevent contaminated foods from reaching the populations of industrialized countries, and primary prevention for the millions in the developing world. Regulatory actions have been taken in various industrialized countries, but their effect is to make developing countries safeguard exports and still to ignore the hazard within the country. The main problem is thus protection of food supplies, for the indigenous populations of those countries that grow and consume the bulk of the susceptible cereals, by improved husbandry.