Millers raise alarm over high aflatoxin in Ugandan maize

Millers have raised concern over the high level of aflatoxin contamination, especially in maize being sold at the border point of Busia.  

The millers said cheap maize coming into the market from Uganda has not dried well, hence the high levels of aflatoxin being reported.

“Those millers with aflatoxin testing kits are shying away from buying the 'cheap' maize but it is still finding its way into the market. #

“The maize we are mopping up locally is well dried and clean but what is coming from the Busia border has not dried according to the required moisture content,” said Kennedy Nyaga, chairman Grain Mill Owners Association.

Aflatoxin contamination in food products is regulated in most countries, with maximum limits ranging from five to 20 parts per billion (ppb) in human food.

Kenya has set a maximum limit of 10 ppb for total aflatoxins in maize and maize products which are similar to limits established by the Codex Alimentarius Commission and the East African Community.

The European Union has the most stringent standard for allowable limits of aflatoxin in maize with a maximum limit of four 4 ppb for total aflatoxin.

Nyaga said most Kenyans have turned to milling maize at the posho mills due to the tough economic times. That has led to low purchasing power and reduced demand for branded maize flour.

“Times are hard but Kenyans should be keen on food safety. Ensure that maize being milled in the posho mills is well dried to avoid aflatoxin contamination,” he said.

In February last year, the Kenya Agricultural Livestock and Research Organization (Kalro) reported of aflatoxin contamination in the maize growing areas of Trans Nzoia and Bungoma counties.

KALRO director general Dr Eliud Kireger attributed this to climate change and the rising temperatures.  

“Due to climate change and the increase in temperatures, we are beginning to see incidences of aflatoxin contamination in areas like Trans Nzoia and Bungoma which are not traditionally known for aflatoxin contamination. We are concerned as these are breadbasket areas,” he said.

He said Kenya is one of the world’s hotspot areas of aflatoxin contamination. Some of the other hotspot areas for aflatoxin are Meru, Tharaka Nithi, Embu, Machakos, Kitui, Makueni, Kilifi, Kwale, Taita Taveta and Kajiado.

Aflatoxin is poison produced by a fungus that resides in the soil and infects crops in the field with the most susceptible crops being maize and groundnuts.

Data from the government shows that about 200 people have died due to consumption of aflatoxin contaminated food in the years 2004 and 2010.

“The hotspots of aflatoxin are in the semi-arid areas, anywhere where the temperature is above 25 degrees Celsius. These areas have been mapped Kireger said.

According to a study published in the Journal of Food Quality in 2023, Kenya is one of the world’s hotspots for aflatoxin contaminations, with a record of what is believed to have been the highest incidence of acute toxicity.

The study was on aflatoxin contamination of maize from small-scale farms practicing different artisanal control methods in Kitui.

The study noted that the country has suffered severe outbreaks of aflatoxin poisoning since the first reported outbreak in 1981. Out of the 20 hospitalised victims, 12 died of liver failure.

In 2004, an acute outbreak of aflatoxin poisoning occurred in Kenya with 317 reported cases and a fatality rate of 39 percent.

“Aflatoxin contamination is known to be prevalent in the Eastern region of Kenya, where home-grown maize is often contaminated during the post-harvest stage of maize grain handling,” the study showed.

The researchers explained that human exposure to aflatoxin occurs mainly through ingestion of contaminated food. The presence of toxins in food can cause acute and chronic effects referred to as aflatoxicoses.

More than five billion people in developing countries are at risk of exposure to aflatoxins through consumption of contaminated foods.

The study shows acute toxicity resulting from exposure to high levels of aflatoxins is a rare event worldwide, although cases have occurred in high-risk regions such as the documented outbreak in the Eastern region of Kenya.

“Acute exposure to high doses of aflatoxin results in patients showing symptoms of jaundice, vomiting, abdominal pain, and liver failure with case fatality rates of up to 40 per cent,” the journal study said.

“Chronic exposure through cumulative ingestion of low quantities of aflatoxin in the diet over a period of time is widespread and is the leading cause of liver cancer in adult populations in developing countries,” the study indicated.

Further, chronic exposure to aflatoxins has been associated with malnutrition and stunted growth in children and suppression of the immune system.

It is estimated that as much as 28.2 percent of annual liver cancer cases in humans globally are linked to exposure to aflatoxin. An estimated 26,000 people in sub-Saharan Africa die annually from aflatoxin-related liver cancers.

The researchers recommended artisanal aflatoxin control technologies that impact aflatoxin contamination.

These include the use of certified maize seeds and drying of maize on tarpaulin mat or raised platforms. Farmers drying maize on bare ground have a high risk of aflatoxins contamination.

They said farms that stored maize in hermetic bags and gunny bags had reduced risk of aflatoxin contaminations.

“We therefore recommend targeted active surveillance to enhance monitoring and changes in levels of aflatoxin contamination of maize,” the researchers said.

“This is in addition to mitigation measures to minimise negative consequences in health and sources of livelihoods for communities,” they said.

“Public health education should be implemented to create awareness amongst the community at risk,” they concluded.

Kalro in collaboration with development partners has developed Aflasafe KE01, which is a biological control agent that suppresses aflatoxin producing fungi in the soil.

A 2kg bag of Aflasafe retails for Sh400.

Experts have urged the government to subsidise Aflasafe as subsidise fertiliser to encourage farmers to use the product.