Alternaria Toxins and Their Importance in Food

Abstract

Members of the genus Alternaria are known to produce compounds that are pathogenic to plants and other test organisms, including animals. Of the more than 30 compounds produced, tenuazonic acid, alternariol, alternariol methyl ether and alterto-xin I are the most toxic to animals. These toxic compounds have been isolated from diseased plant tissue and could be a problem with foods, although only tenuazonic acid has been isolated in small amounts from wholesome foods. A number of Alternaria spp. can produce these compounds and some species produce many of the compounds. Growth conditions under which the compounds are produced are not well-defined; generally the optimum temperature for their production is near 20°C. The genus Alternaria is widely distributed in soil, household dust and decaying organic material. Alternaria spp. require relatively moist conditions for growth, i.e., a water activity above 0.84 (144). Many species of Alter-naria are plant pathogens and some are common post-harvest decay organisms of fruits and vegetables. Many of these plant pathogens are host specific and at least some of their toxins also appear to be host specific. Some Alternaria toxins have adverse effects on other microorganisms and/or animals or mammalian cells. So far, over 30 different metabolites have been isolated as potential toxins from cultures of Alternaria spp.