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Confronting the aflatoxin challenge in Africa

November 21, 2016

Aflatoxins are one of the many ‘silent’ threats to the African continent’s food supply. A new report points the way to fighting aflatoxin contamination and reducing exposure levels.

Aflatoxins are highly poisonous compounds produced by the Aspergillus fungus, which grows in soil. Several of the food crops grown in Africa, such as cassava, chili, groundnuts, maize, rice, sorghum, teff, and major cash crops such as coffee, cocoa, tea and sugarcane have been found to be contaminated with these dangerous toxins. They have also been found in processed foods such as peanut butter and foods from animal sources like egg and milk.

Aflatoxins also cause cancers in humans and animals. According to the International Agency for Research on Cancer, aflatoxin B1, is the most potent natural carcinogen known. About 26,000 Africans living south of the Sahara die of liver cancer every year through chronic aflatoxin exposure.

Groundnut Maize nigeriaLeft: Aflatoxin B1 contamination in maize in Nigeria. Right: Aflatoxin B1 contamination in groundnuts in Nigeria. Source: Adapted from: Abt Associates, 2012.

Because of their potency and the wide range of commodities they affect, aflatoxins pose serious risks to human health, agricultural production and trade. As part of its increased focus on aflatoxin mitigation for improving nutrition outcomes in Africa, CTA and the Partnership for Aflatoxin Control in Africa (PACA) have launched a working paper entitled Improving the Evidence Base on Aflatoxin Contamination and Exposure in Africa: Strengthening the Agriculture-Nutrition Nexus. The report is the result of a study commissioned by CTA and PACA in 2015.

Led by Professor Sheila Okoth of the University of Nairobi, the report is based on a detailed review of over 800 references in the published literature.

"Aflatoxins can be produced anytime and anywhere along the food and feed value chains. The presence of aflatoxins in food and feed have adversely affected the health of the population and the ability of the continent to trade with the rest of the world,"
Professor Sheila Okoth, University of Nairobi

A substantial body of knowledge is available on the aflatoxin challenge that plagues African farmers, other agri-entrepreneurs and governments, but it is not being put into practice. Judith Francis, CTA's Senior Programme Coordinator, Science and Technology Policy, who oversaw the project said that farmers, consumers, processors, financiers, governments need to act in unison with the research community.

"The report demonstrates that there is enough evidence to support joint action to solve the aflatoxin problem but key stakeholders do not seem to be receiving or are not sufficiently exposed to this evidence-based information, despite the significant research that has been carried out so far in the continent". 
Judith Francis, CTA

Aflatoxin contamination occurs at every stage of the supply chain, from pre-production to post-harvesting, marketing and distribution. Aflatoxin accumulates after harvest, especially when commodities are stored under hot, humid conditions. This is a particular challenge for Africa, where the environmental conditions are just right. In the absence of adequate testing and certification facilities, aflatoxin-susceptible commodities that do not meet internationally accepted standards are often rejected by major buyers, processors and traders and by international regulatory agencies. The continent loses between €400 and €600 million a year in export earnings. However, it is not only international trade that suffers: farmers, processors and traders also lose. The domestic and regional trade also suffer.

At high doses, aflatoxins can cause acute poisoning and death. Contaminated maize in Kenya, cassava in Uganda and cereals in Tanzania have caused deaths in humans, usually due to liver cirrhosis. On the other hand, chronic lower-level doses – which may even be inhaled or absorbed through the skin – can cause liver cancer and chronic immunosuppression. All doses have a cumulative effect on increasing the risk of cancer.

The toxins are also associated with severe under nutrition; kwashiorkor and poor growth in young children. Blood samples from new-born infants in Ghana, Kenya, Nigeria and Sudan have tested positive for aflatoxins.

“Effective management requires wholesale change and is knowledge intensive. Joint public and private investment is key to support holistic actions for aflatoxin mitigation with greater impact. A multi-actor, multi-pronged approach is needed from farm to fork, pre-production to postharvest, marketing and distribution supported by an enabling policy, regulatory and institutional framework, including laboratory infrastructure, public education and adequate financial and trained human resources”.
Amare Ayalew, Program Manager, PACA Secretariat at African Union Commission

African farmers, producers, traders and consumers know little about aflatoxins and the risks associated with them. Knowledge is only high in areas where acute outbreaks have occurred, and more so among educated populations. In fact, the report shows that some food commodities routinely sold on African markets are contaminated in some way. This is compounded when produce that has been rejected for local processing or for export is redirected into local food and feed value chains.

Significant investments have been made by the research, academic and donor communities and a range of technologies and interventions have been developed and piloted. The report demonstrates that no single technology or intervention is enough to fight the aflatoxin issue in Africa. The challenge of controlling aflatoxin contamination persists, with continued negative impacts on human health, agri-businesses, trade and socio-economic development, despite the vast knowledge base. Further research and investment need to be better coordinated and farmers, consumers and governments engaged as key stakeholders in promoting good practices, to achieve greater impact in controlling aflatoxin. Priority should be given to building farmer's capacity in adopting such good practices in agriculture and post-harvest management and manufacturers' (micro, small and medium) in good manufacturing practices.

Investing in public education and communication, especially targeting the poor, must be a priority for countries in the fight against aflatoxins. Studies have shown that consumers and buyers are willing to pay a premium for aflatoxin-free products. This should motivate the governments to enact and enforce legislation to ensure that a wider cross-section of Africans can have confidence in the safety of the food supply.

The CTA/PACA report shows that national regulations to govern aflatoxin contamination are pre-requisites for success in containing the threat. And enforcing regulations at every stage of a commodity's value chain though difficult, given the small-scale farming systems and informal markets and trade that are so common on the continent, must be comprehensively addressed. The ideal situation is for the continental partners to agree on and apply stringent standards for controlling aflatoxins in food and feed and jointly enforce the regulations. Harmonising regional policies and aligning them with those of international trading partners such as the European Union will not only enhance regional trade but increase access to international markets. This must be backed up by sampling and testing of foods available in local markets and for export, as is the case in developed countries.

Building up laboratory infrastructure to conform to international standards, though costly, will also expand market opportunities for African farmers, traders, processors and other value chain actors. And building new and strengthening existing strategic partnerships including with the private sector who are already engaged in good practices such as self-regulation to ensure the quality and safety of the food and feed supplied in local and regional markets will contribute to achieving greater impact in controlling aflatoxin contamination in the continent.

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