Ibadan, Nigeria
April 26, 2009
Researchers at the Ibadan-based
International Institute of
Tropical Agriculture (IITA), 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.
Africa has complex problems that plague agriculture and
people's lives. We develop agricultural solutions with our
partners to tackle hunger and poverty. Our award winning
research for development (R4D) is based on focused,
authoritative thinking anchored on the development needs of
sub-Saharan Africa. We work with partners in Africa and beyond
to reduce producer and consumer risks, enhance crop quality and
productivity, and generate wealth from agriculture. IITA is an
international non-profit R4D organization since 1967, governed
by a Board of Trustees, and supported primarily by the CGIAR. |
|
