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Scientists Find Way to Limit Deadly Toxin in Maize


Fears of poisoning by aflatoxin may soon be a thing of the past. The toxin affects many African staples and exports, including groundnuts and maize. Produce contaminated with aflatoxin can kill – and has resulted in a drop in the shipment of some African crops abroad.

But scientists have now found a way to destroy aflatoxin in maize. They say the same method could likely eliminate or reduce the toxin in groundnuts as well. Voice of America English to Africa Service’s Isyaku Ahmed in Kano reports that scientists have discovered a way to drastically reduce the amount of the fungus Aspergillus, which produces the toxin aflatoxin in maize. The effort brought together experts from the International Institute of Tropical Agriculture in Nigeria, the United States Department of Agriculture and three universities.

The institutions of higher learning included the University of Arizona, the University of Ibadan in Nigeria and the University of Bonn in Germany.

The method uses benign forms of the fungus to crowd out the toxic ones.

The researchers collected more than four thousand strains of Aspergillus – nearly one-fourth of which did not produce the toxin. In the end, scientists narrowed their testing to eight strains found in laboratories and in the fields.

They applied the benign samples with the toxic ones to the soil and found the benign strains were able to eliminate almost all of the toxic ones.

The next step is to test the results after releasing a number of strains in large-scale field trials at several sites in Nigeria.

Dr. Ranajit Bandyopadhyay is a plant pathologist with the International Institute of Tropical Agriculture, the IITA. He told the press, “The bio-control project is at an exciting stage, where we need to finally prove that the atoxigenic strains can drastically reduce aflatoxin contaminations in real farming situations in Africa.”

Peter Cotty is a leading scientist from the United States Department of Agriculture and a member of the research team on aflatoxin reduction in crops. He says it’s crucial to use non-toxin-producing but indigenous strains to ensure that the strains they release will be highly competitive under local conditions. They also pose less of an ecological risk compared to imported strains.

The Aspergillus fungus can contaminate a crop before harvest or during storage. Among the plants vulnerable to it are those weakened by drought or high humidity. The fungus thrives in soil and in decaying vegetation, including grains.

Consuming too much aflatoxin can cause liver cancer and suppress the immune system, making the body more susceptible to disease.

And it is a major risk factor among children, where it is linked to Kwashiorkor. That’s because the toxin also reduces the absorption of nutrients when digested.

The toxin also reduces growth and development in children. It can pass from mother to child through the umbilical cord.

In sub-Saharan Africa, about half of the 4.5 million deaths among children younger than 5 years have been associated with malnutrition and growth impairment.

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