Keeping deadly poison off key crops along the value chain in Tanzania
Increasing crop production does not always lead to more food and a healthier population. In some cases, the consumption of the crops and their products may instead lead to serious health problems in both human beings and livestock and even death. One such instance is when the crops are contaminated with mycotoxins, poisonous substances produced by naturally occurring fungi that attack crops while in the field and in all handling practices before, during, and after storage.
Some of the well-known mycotoxins include aflatoxins, which are produced by the Aspergillussp.; and fumonisins which are produced by Fusarium sp. Aflatoxins are carcinogenic and can lead to death in acute poisoning cases. Fusarium is suspected to reduce body immunity and retard the growth of children.
One of the objectives of Africa Rising is to ensure the food produced by farmers in the target areas is free from mycotoxins or has levels that are within the allowable limits and therefore fit for human and livestock consumption and for regional and international trade. This is done by analyzing the levels of mycotoxins in maize and beans along the value chain.
So far, over 700 samples of maize and beans have been collected from households in three villages in Babati District (Tanzania): Seloto, Sabilo, and Long. The researchers collected samples of maize and beans from the field and beans from storage. The team will soon collect maize from storage to complete the targeted quantity of samples required for the analysis.
The researchers also used the opportunity to create awareness on mycotoxins among farmers, village heads, and extension staff and distributed factsheets which have been translated into Swahili on mycotoxins.
“Once all the samples are collected and the analyses accomplished, we will be able to determine if the levels of myctotoxins in the targeted villages are alarming or not and this will determine the next course of action. The results from the analyses will be compared and related to the information collected from each household that provided samples to be able to determine if there are any practices contributing to mycotoxin contamination,” says Simon Boniface from IITA, who is working on the project.
Boniface says contamination of the crops occurs either in the field as these fungi are naturally found in the soil or at any stage during harvesting, handling, and storage. Contaminated crops remain infected as currently there are no effective and reliable means of decontamination.
“The most available means of controlling and managing the problem is to avoid creating a conducive environment for the fungi. Alternatively, biological control using a strain of the same fungi but which do not produce toxins has proved very effective in controlling the toxin producing strain in other countries like USA and Nigeria to control aflatoxin produced by Aspergillus sp.,” he said.
He points out that the common practice of spreading maize and beans on the bare ground to dry can lead to contamination of the two important food crops in the area as the fungi are found in the soils.
This component of the project is being led by Fen Beed of IITA in partnership with Dr Martin Kimanya from the Nelson Mandela African Institute of Science and Technology (NM-AIST). It also involves an MSc student from Sokoine University of Agriculture (SUA).
Story by Catherine Njuguna (IITA)
This story was published as part of an Africa RISING special issue of the IITA Bulletin (1 August 2013)