Natural occurrence of aflatoxins in groundnut (Arachis hypogaea L.) from eastern Ethiopia

Aflatoxins are highly toxic and carcinogenic chemical substances produced by Aspergillus spp. on variety of agricultural commodities including groundnut. This study was conducted with the objective to assess total aflatoxin concentration in groundnut samples. One hundred and twenty groundnut samples collected from farmers' stores and markets were used for aflatoxin analysis in an ELISA test. Of these, 93 were positive while the remaining 27 were negative. The total aflatoxin levels in the positive samples varied between 15 μg/kg and 11,900 μg/kg. The current results clearly revealed heavy contamination of groundnut samples in Ethiopia, which is far beyond the Food and Agricultural Organization of the United Nations/World Health Organization (FAO/WHO) standard (15 μg/kg) and the European Union (EU) limit i.e. 4-15 μg/kg, depending on the end use of groundnut, suggesting the urgent need to apply control measures against toxicogenic fungi and associated mycotoxins. The major factors for contamination of groundnuts by aflatoxin were suggested to be pre- and post-harvest environmental factors, and poor management practices including delayed harvesting, mechanical damage at the time of harvesting, and limited curing and drying before storage.