Aflatoxins, a group of deadly toxins, are endangering staple foods in East Africa

A section of just-harvested maize is stored in a local method where they are dried by hot air. Photo by Goodhope Amani, used with permission.

Aflatoxins, a group of toxic compounds produced by certain fungi, are posing a grave threat to agricultural crops in East Africa.

These toxins are commonly found on crops such as maize (corn), peanuts, cottonseed and tree nuts. The main fungi that produce aflatoxins are Aspergillus flavus and Aspergillus parasiticus, which thrive in warm and humid regions. Aflatoxin-producing fungi can contaminate crops at any stage, from crop cultivation to storage.

The problem of aflatoxin is particularly prominent in tropical regions with moderate climates, such as Tanzania, Kenya and Uganda. In 2016, the Tanzania government reported approximately 14 deaths linked to the consumption of aflatoxin-contaminated food.

Global Voices interviewed Dr Masolwa Ng'wanasayi,  a gastroenterologist from the Aga Khan Hospital, Dar es Salaam, who shed light on how aflatoxin slowly kills people. He said the most vulnerable individuals are those living in rural areas:

In urban areas, the situation is somewhat better, especially if you purchase food certified by the Tanzania Bureau of Standards (TBS), which ensures aflatoxin-free products. Aflatoxin's harm is not immediate; it takes 10-15 years to manifest. Prolonged exposure damages liver cells, reducing their ability to regenerate and repair, ultimately leading to the onset of cancer. Past research conducted in Africa reveals that at least 40 percent of liver cancers are attributed to aflatoxin exposure.

Dr Masolwa Ng'wanasayi speaking with Global Voices at the Aga Khan Hospital, Dar es Salaam. Photo by Goodhope Amani, used with permission.

Dr Ng'wanasayi explained that aflatoxin does not only affect human beings, but it can also affect animals such as goats, and cows. Consuming animal products contaminated by the toxin can pose risks to human health. He recommended regular check-ups for early detection and treatment.

In a conversation with Global Voices in Dar es Salaam, Dr. George Mahuku, a senior plant pathologist with the International Institute of Tropical Agriculture (IITA) for Eastern, South and Central Africa, pointed out the impact of climate change on aflatoxin contamination:

Aflatoxin is a major concern, especially in tropical regions, as the environmental conditions are conducive for the growth of this fungus. We are currently witnessing a rise in reports of aflatoxin contamination due to climate change. This fungus thrives in drought or high-temperature conditions, and it particularly flourishes when plants are stressed. This is a significant issue within East Africa.

Dr. George Mahuku after an interview with Global Voices at his office in Dar es Salaam. Photo by Goodhope Amani, used with permission.

Dr. Mahuku adds that the problem begins in the fields since the fungus resides in the soil. To mitigate aflatoxin contamination, it is crucial to protect crops in the field. This involves using improved crop varieties, safeguarding grains from insect damage, ensuring well-drained harvesting, and removing damaged grains. These measures can significantly reduce contamination. Additionally, agricultural researchers have developed a bio-control method called Aflasafe, which farmers can use during crop planting. Aflasafe displaces the toxin-producing fungi, leading to an impressive 80-100 percent reduction in contamination, with 100 percent efficiency if applied in a timely manner.

Dr. Mahuku also noted that the significant challenge of fighting aflatoxin in the region is the limited awareness among farmers, a dangerous situation compounded by the ongoing effects of climate change.

The most substantial issue with aflatoxin is that the damage it inflicts is invisible; it is tasteless and odourless. We are essentially combating an unseen adversary. Convincing farmers to adopt bio-control measures for a problem they cannot readily observe presents a major hurdle.

Eliamani Singo, after a long day at the farm. Photo by Goodhope Amani, used with permission.

Eliamani Singo, a resident of Kabuku village in the Tanga region of eastern Tanzania, has been cultivating maize for over 20 years. While he has taken careful measures, from seed selection to post-harvesting, he is unaware of the issue of aflatoxin and its impact on human health. He told Global Voices:

During harvesting, I make sure that the maize is thoroughly dry and after that I store it in elevated  location to continue the drying process. On the issue of aflatoxin, I don’t have an idea, thus agriculture specialists should visit farmers to disseminate the knowledge.

According to estimates from the World Health Organization (WHO),  approximately 500 million people are exposed to unsafe mycotoxin levels, with the majority of them living in Sub-Saharan Africa. Maize and groundnuts, among other staples in Africa, are highly susceptible to aflatoxin contamination. This underscores the need for governments to prioritize food safety efforts in the region.

There is no doubt that aflatoxin poses a significant threat not only to human health but also to food security in the region. Agriculture research institutes such as the International Institute of Tropical Agriculture (IITA)  are working to discover more effective ways of addressing this issue. The Tanzania government has also taken steps to educate farmers on proper farming practices, seed selection and safe storage methods.

Initiatives like the TANIPAC project focus on constructing modern storage facilities for agricultural crops and teaching farmers best practices, with plans for nationwide expansion. However, addressing the aflatoxin issue necessitates a collective effort as it transcends borders.

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