Researchers from the Makerere University in Kampala have warned that Ugandans are at high risk of contracting liver cancers and hepatitis B after laboratory tests revealed high concentrations of fungi-produced aflatoxin in staple food crops that include maize, millet, sorghum and cowpea.
According to a report released by Professor Archileo Kaaya of the Makerere University Department of Food and Technology, laboratory tests dating back to the year 2000 have revealed that nearly 60% of locally produced grains may are unfit for human consumption.
The research found that most of the maize, groundnuts, beans and sorghum sold on the local market are infected with high levels of aflatoxins, which contain carcinogens that cause liver cancer.
Babies were found to be more exposed to aflatoxins because they get the more toxins from their mothers’ milk. HIV positive people were also found to be at risk as the high concentration of toxins in foods further weakens the immune system.
“Groundnuts are much more contaminated than maize, but sorghum is even worse, especially the new variety called ‘epur pur’, which is commonly used for brewing beer. We found that the levels can be as high as 1 000 parts per billion, which is hazardous when compared to just 10 parts per billion stipulated by East African regional standards,” he said.
HANDLING AND STORAGE
Kaaya attributed the aflatoxin contamination to improper product handling procedures by farmers, who dry produce on bare ground and increase chances of pollution due to ground moisture or rain.
Apart from the staple foods, improperly stored animal feeds were identified as another source of the aflatoxins that end up threatening public health. The study found that the widespread tendency to use spoilt or rotten grains to make livestock feed allows for the passing of toxins down the value chain as animals that eat infected feeds may die or infect milk, meat or eggs intended for human consumption.
“So the grains that you think have been thrown away end up in milk and meat and in addition to causing liver cancer. They are also associated with the effects of enhancing the hepatitis B virus. They are also linked to stunting in children. Remember, these are our staples and we start giving them to children very early and we continue to do so throughout their lives,” said Kaaya.
To reduce aflatoxin contamination in grains, farmers have been urged to use dry surfaces that are less prone to ground moisture to dry crops,to and store them in cool, dry places to avoid contamination.
Farmers were also advised to feed their animals using natural grasses as opposed to commercial stock feeds, which can be a source of aflatoxin infection. The study also found grains from lowland areas to be at higher risks of contamination due to high tropical temperatures, which favour the breeding micro-organisms.