Survey of some cereal grains and legume seeds for aflatoxin contamination in the Sudan.

Aflatoxins were detected in some cereals and leguminous seeds collected from 2 cities in the Sudan (Wad Medani and Khartoum). The levels of the aflatoxins in these seeds were below the reported hazard threshold. Sound intact seeds contained low or no aflatoxins compared to significantly higher levels detectable in damaged and mouldy seeds of the tested crop plants. The optimum temperature for aflatoxin production was variable for different isolates of A. flavus. The optimum is 30 degrees C for the maize isolate and only 20 degrees C for the haricot bean isolate. Large amounts of aflatoxins B1, B2 and G1 were produced by the 2 isolates while aflatoxin G2 was only produced by the haricot bean isolate at optimum temperature. Aflatoxin B1 had significantly affected seed germination and plant development in both maize and haricot bean plants grown from seeds soaked in aflatoxin solutions. The influence was increasing with increasing concentration of the toxin.