Aspergillus flavus colonization and aflatoxin contamination of groundnut in Sudan
1989
Ahmed, N.E. | Younis, Y.M.E. | Malik, K.M.
The effects of irrigation regimes and date of harvesting on preharvest infection by Aspergillus flavus and aflatoxin contamination of seed of four commercial and two other groundnut cultivars were studied. Groundnuts watered at 1-, 2-, and 3-week intervals and harvested at the normal time, and at 1 week after this time were free from A. flavus colonization and aflatoxin contamination. A. flavus colonized a low percentage (2.7-7 per cent) of groundnuts left in the soil for 6 weeks after harvest. No aflatoxin contamination was detected. Wilt diseases and insect damage predisposed seeds to preharest A. flavus infection and aflatoxin contamination. Groundnuts stored for 3 months in a well-ventilated room with an average temperature of 15 deg C were colonized at a low level but with no aflatoxin contamination. Infection increased with time in storage. Groundnuts harvested 1 week before maturity were most affected by A. flavus infection of seeds in storage, but there were no differences between genotypes. Groundnuts stacked in sacks at shelling sites were sampled, 4 per cent were contaminated, with an average aflatoxin content of 11 micro g/kg. Those sampled at oil mill sites were 15 per cent contaminated with an average aflatoxin content of 20 micro g/kg. Groundnuts left in the soil for 2-3 weeks after harvest in trials on the Gezira and Rahad irrigation schemes had 12 per cent of samples contaminated, with an average aflatoxin content of 10 micro g/kg
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