Tropentag, October 5 - 7, 2004 in Berlin "Rural Poverty Reduction through Research for Development and Transformation"

Strategies for the Management of Mycotoxins in Maize in Benin, West Africa

¹International Institute of Tropical Agriculture (IITA), Biological Control Center for Africa, Benin
²International Institute of Tropical Agriculture (IITA), Nigeria
³University of Bonn, Institute for Plant Diseases, Germany

Abstract

According to the FAO, 25% of the world's food crops are affected by mycotoxin, which negatively impact human health, food trade, food availability and consumption. People are primarily exposed to aflatoxin through consumption of contaminated foods. It was shown that 99% of children monitored in Benin and Togo had high aflatoxin levels in the blood, with some of the highest AF-alb levels ever measured in children. The study showed a striking association between aflatoxin exposure and impaired growth. Depending on ecozone and season, up to 57% of stored maize samples were contaminated with aflatoxins. Aflatoxin contamination is influenced by the populations of toxin producing fungi that reside in the soil, cob feeding lepidopteran insects, invading weevils and other beetles; cultural management of the crop, environment and plant stress; and genotype.

In participatory trials in Benin and Togo, crop and store management options were developed to reduce mycotoxin contamination of maize and their economic viability was assessed. Drying and sorting of maize are techniques that can reduce aflatoxin contamination in maize. Similar technologies have been identified for fumonisin contamination in Benin. The study showed that F. verticillioides was the predominant Fusarium species found in all maize samples. Fusarium incidence was significantly higher when maize was stored on a cemented floor in a house (40.3±17.4%) than in the other systems. The lowest Fusarium incidence was recorded when maize was stored in a bamboo granary (25.5±13.5%) (p = 0.04). This suggests that storage systems used by farmers may affect Fusarium and Aspergillus infection on maize, if these systems create conditions favourable to fungal growth. Damage by lepidopterous pests was significantly and positively correlated with both Fusarium infection (r = 0.802, p < 0.01) and fumonisin contamination (r = 0.852, p < 0.01). Insect damage was positively correlated to aflatoxin content (r=0.20, p < 0.01).

The control of mycotoxigenic fungi with management practices easily accessible and affordable to farmers' will lower the risk that mycotoxins pose to human health and improve health and human well being.

Keywords: Aflatoxin, food quality, fumonisin, management

Contact Address: Kerstin Hell, International Institute of Tropical Agriculture (IITA), Biological Control Center for Africa, 08 BP 0932 Tripostal, Cotonou, Benin, e-mail: k.hellcgiar.org