Mycotoxins are toxic secondary metabolites of moulds belonging essenti
ally to the Aspergillus, Penicillium, and Fusarium genera. They can be
produced on a wide range of agricultural commodities and under a dive
rse range of situations. Due to their various toxic effects and their
good thermal stability, the presence of mycotoxins in foods and feeds
is potentially hazardous to the health of both humans and animals. Thi
s paper reviews the 6 major chemical types of mycotoxins thought to be
of importance from the agricultural point of view (aflatoxins, ochrat
oxin A, patulin, fumonisins, deoxynivalenol and zearalenone), by givin
g an idea of the levels that tend to be found naturally, and the exten
t and frequency with which they have been reported worldwide. Of prime
importance in the usefulness of such a survey is the reliability of d
ata incorporated, which, in turn, depends on the representativeness of
samples tested and the nature and validity of the analytical methods
used. Thus the present review is essentially based on scientific liter
ature published from the early 1990's until late 1997.