Zearalenone - possibly the most significant mycotoxin threat
BELINDA JANSE VAN RENSBURG AND DR BRADLEY FLETT, ARC-GRAIN CROPS INSTITUTE
The term mycotoxin is derived from the word “myco” in the name for the division Eumycota of plants to which moulds belong and the word “toxin”, which means poison. The three major genera of mycotoxinproducing fungi are Aspergillus, Fusarium and Penicillium spp. Mycotoxins are a worldwide problem due to three main reasons.
Firstly they affect human and animal health, secondly there are huge economical losses associated with contaminated foods, feeds and loss in animal productivity and thirdly, mycotoxin contamination has a serious impact on international trade commodities. The Food and Agriculture Organisation (FAO) of the United Nations has estimated that 25% of the world’s food crops are contaminated by mycotoxins every year.
Fusarium graminearum is the major fungus species responsible for production of the mycotoxin zearalenone in maize. F. graminearum can infect a number of crop-plant species, which implies that zearalenone could occur in a variety of foods and feeds. In reality cereals grains such as wheat, barley, sorghum and especially maize are the most important sources of zearalenone contamination in human and animal diets. In recent studies by Ms M. Mavhunga of the ARC-Plant Protection Research Institute, levels of zearalenone were determined in maize collected from various cultivar trials conducted all over South Africa.
Zearalenone levels as high as 2 000 parts per billion (ppb) were found at certain localities. It appears that there are strong seasonal and geographic effects on the incidence of zearalenone. These levels are often far above the maximum allowable limits set by the European Union (EU) and the Food and Drug Administration (FDA) of the United States of America (USA).
Publication: January 2010