Research promises end to aflatoxin contamination and reduction
in $1.2bn global trade losses
By Godwin Atser
Press Release | Sun, 26 Apr 2009
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
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,
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