How much aflatoxin is too much?
Christensen (1972), over a period of several years, examined 100 different samples of black pepper from all over the world. In dilution cultures of these samples, the number of fungus colonies in whole or ground black pepper averaged 52,000 per gram/black pepper and the upper range was over half a million per gram. These colonies were mostly of A. flavus, A. ochraceus and A. versicolor. All three species are known to be aflatoxin producers. Some samples of ground pepper were caked lightly with fungus mycelium when first opened in the laboratory and with time, a number of these became solidly caked with mycelium. How heavily contaminated is 52,000 to 500,000 colonies of fungi, per gram? Lets make a comparison for what is acceptable levels of fungal colonies isolated in other food products at the time Christensen published his results. Wheat, for example, that is intended for milling into flour seldom contains no more than a few thousand colonies of fungi per gram of grain. If barley has
