IARC MONOGRAPHS ON THE EVALUATION OF CARCINOGENIC ...

ANNEX. AFLATOXINS IN FOODS AND FEEDS:
FUNGAL SOURCES, FORMATION AND
STRATEGIES FOR REDUCTION
1. Major Mycotoxins and Crops
Five types of mycotoxins of agricultural importance occur in staple crops (Miller,
1995): aflatoxins, fumonisins, ochratoxin A, specific trichothecenes (deoxynivalenol and
nivalenol) and zearalenone. These mycotoxins can cause various forms of poisoning in
animals and in humans, and some are carcinogenic (Table 1). Aflatoxins are produced by
Aspergillus species in nuts and oilseeds, particularly maize, peanuts (groundnuts) and
cottonseed, especially in tropical and subtropical climates. Fumonisins are produced by
Fusarium verticillioides (formerly known as F. moniliforme) and the closely related
F. proliferatum, in maize and sorghum. Ochratoxin A occurs in cereals as a result of
growth of Penicillium verrucosum and in other crops, especially grape products (grape
juice, wines and dried vine fruit), coffee and long-stored commodities as a result of
growth of several Aspergillus species. Deoxynivalenol, nivalenol and zearalenone are
formed as a result of growth of F. graminearum and F. culmorum in maize, wheat, barley
and other small grains (JECFA, 2001). Ergot, the toxic product of the fungus Claviceps
purpurea which grows on rye and to a lesser extent on other grains, was historically a
significant source of epidemic poisoning in Europe, but due to effective inspection of
grain it is rarely a public health problem today in Europe and North America.
Some crops are infected by only one toxigenic fungus: aflatoxins in peanuts and
cottonseed, and ochratoxin A in susceptible crops are usually found by themselves. In
small grains, trichothecenes and zearalenone usually occur together as the result of
infection by one or more Fusarium species. Of greater importance, fumonisins and
aflatoxins, and to a lesser extent trichothecenes and zearalenone, frequently occur simultaneously
in maize. Any conclusions regarding reduction strategies should take this into
account.
This Annex deals only with aflatoxins, but many of the points made have relevance
to the other toxins.
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