Natural occurrence of mycotoxins in staple cereals from Ethiopia.

The occurrence of mycotoxins in barley, sorghum, teff (Eragrostis tef) and wheat from Ethiopia has been studied. Samples were analyzed for aflatoxin B(1) (AFB1), ochratoxin A (OTA), deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN) using high performance liquid chromatography (HPLC) and for fumonisins (FUM) using enzyme linked immunosorbent assay (ELISA). AFB1 and OTA were detected in samples of all the four crops. AFB1 was detected in 8.8% of the 352 samples analyzed at concentrations ranging from trace to 26 microg kg(-1). OTA occurred in 24.3% of 321 samples at a mean concentration of 54.1 microg kg(-1) and a maximum of 2106 microg kg(-1). DON occurred in barley, sorghum and wheat at 40-2340 microg kg(-1) with an overall incidence of 48.8% among the 84 mainly 'suspect' samples analyzed; NIV was co-analyzed with DON and was detected at 40 microg kg(-1) in a wheat sample and at 50, 380, and 490 microg kg(-1) in three sorghum samples. FUM and ZEN occurred only in sorghum samples with low frequencies at concentrations reaching 2117 and 32 microg kg(-1), respectively. The analytical results indicate higher mycotoxin contamination in sorghum, which could be related to the widespread storage of sorghum grain in underground pits leading to elevated seed moisture contents. This is the first report on the occurrence of OTA in teff.