The influence of storage practices on aflatoxin contamination in maize in four agroecological zones of Benin, west Africa

Aflatoxin level in 300 farmers' stores in four agro-ecological zones in Ben in, a west African coastal country, were determined over a period of 2 year s. At sampling a questionnaire was used to evaluate maize storage practices . Farmers were asked what storage structure they used, their storage form, storage period, pest problems in storage and what was done against them. Be ninese farmers often changed their storage structures during the storage pe riod, transfering the maize from a drying or temporary store to a more dura ble one. Most of the farmers complained about insects damaging stored maize , Often, storage or cotton insecticides were utilized against these pests. Regression analysis identified those factors that were associated with incr eased or reduced aflatoxin. Maize samples in the southern Guinea and Sudan savannas were associated wit h higher aflatoxin levels and the forest/savanna mosaic was related to lowe r toxin levels. Factors associated with higher aflatoxin were: storage for 3-5 months, insect damage and use of Khaya senegalensis-bark or other local plants as storage protectants. Depending on the agroecological zone, stora ge structures that had a higher risk of aflatoxin development were the "Ago ", the "Secco", the "Zingo" or storing under or on top of the roof of the h ouse. Lower aflatoxin levels were related to the use of storage or cotton i nsecticides, mechanical means or smoke to protect against pests or cleaning of stores before loading them with the new harvest. Fewer aflatoxins were found when maize was stored in the "Ago" made from bamboo or when bags were used as secondary storage containers. (C) 2000 Elsevier Science Ltd. All r ights reserved.