Research promises end to aflatoxin contamination and reduction in $1.2bn global trade losses

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By Godwin Atser
Press Release | Sun, 26 Apr 2009


Researchers at the Ibadan-based International Institute of Tropical Agriculture, the African Agricultural Technology Foundation, Kenya, and the United States Department for Agriculture have demonstrated the ability of natural Nigerian fungi to reduce the concentrations of aflatoxins in maize and, as a result, reduce global trade losses estimated at $1.2bn.

The researchers through a partnership have created a safe natural biological method of eliminating aflatoxin contamination of food crops, IITA says today.

Aflatoxins are chemical poisons produced mainly by the fungus Aspergillus flavus in maize, groundnuts, cassava, and yam chips. These toxins are also potent causes of cancer and suppress the immune system causing humans and animals to be more susceptible to diseases.

Besides, aflatoxins are also non-tariff barriers to international trade since agricultural products that have more than permissible levels of contamination are rejected in the global market.

Though losses faced by the global economy are estimated at $1.2bn, African economies lose about $450m annually to aflatoxin contamination.

Aflatoxin is a silent killer. It undermines human health and stunts the growth of children but is not often visible on the corn when purchased. says Dr. Ranajit Bandyopadhyay, IITA Pathologist at a meeting organized by the AATF in collaboration with IITA. The meeting, which ended on Friday, examined the prospects of a biological method for drastically reducing aflatoxin contamination.

On-station field trials of the biocontrol method in Zaria, Ikenne, Mokwa and Ibadan showed 50 to 99% reductions in aflatoxin contamination of maize.

Under the biocontrol, native strains of Aspergillus flavus that do not produce aflatoxins (called atoxigenic strains) can be applied in order to alter the fungal community on crops and throughout an area so that maize becomes less contaminated with aflatoxins. When applied appropriately, these native atoxigenic strains competitively exclude aflatoxin producers.

This competitive exclusion principle of biological control will be used as a new type of aflatoxin intervention strategy to mitigate the negative effect of aflatoxins on human health and trade in Kenya and Nigeria.

Dr. Peter Cotty of the Agricultural Research Service, United States Department of Agriculture, who collaborated with IITA on the project, says natural populations of Aspergillus flavus consist of toxigenic strains that produce copious amounts of aflatoxin and atoxigenic strains that lack this capacity. He explains that competitive exclusion works by applying selected native atoxigenic strains to out-compete and exclude aflatoxin-producers during colonization of grains and thereby reducing levels of aflatoxin contamination. There are several atoxigenic strains native to Nigeria that are useful for reducing aflatoxins.

Bandyopadhyay says atoxigenic strains can be directed at reducing aflatoxin contamination in several crops throughout an area simultaneously.

Manipulation of the composition of fungal communities (i.e., replacing high aflatoxin-producers with their cousins that do not produce aflatoxins) so that high aflatoxin-producers are less common, is a viable approach for reducing aflatoxin contamination throughout all crops grown in a target area, he says.

According to Bandyopadhyay, atoxigenic strains for use in biocontrol have been identified for use in Kenya and Nigeria by USDA-ARS and IITA. On April 24th a group of stakeholders including farmers, government officials, the food and feed industry and NGOs expressed the desire to convert this technology into the reality of a readily available product for producing safer maize in Nigeria where this technology will be used for the first time in Africa.

Source: Godwin Atser



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