The fungus that has killed over 100 people in Kitui, Machakos and Makueni districts might be just the tip of the iceberg as far as aflatoxin contamination is concerned.
Even those who buy only from exclusive supermarkets are not spared, according to research findings by Dr George Siboe, Senior Lecturer at the Department of Botany, University of Nairobi .
Dr Siboe has isolated aflatoxins, among other mycotoxins, from popular brands of maize flour currently in the Kenyan market.
In a comprehensive study, Dr Siboe and his colleagues collected 174 samples of flour packed in 90 kg bags and 2kg packets in Nairobi from different selling points that included ordinary grocery stores, kiosks, supermarkets and open air- markets. The samples were tested for fungal infestation and were all found contaminated with moulds that produce aflatoxins, fumonisins and ochratoxins, among other mycotoxins.
Sixteen fungal species were isolated from the flour with 70 per cent of the 172 samples found to be contaminated with aflatoxins. Fifty-five percent of the samples were also laced with similar fungal poisonous substances.
The high infestation of maize flour seems to be an eye-opener that disaster is lurking as a result of poor quality control of food commodities from the farm to the market.
According to the health officials, aflatoxins are highly poisonous chemical compounds usually found in moulds that affect maize, millet, sorghum, wheat, rice, cassava, yams and groundnuts among other food crops.
A consultant food technologist and biotechnologist based in Nairobi, Mrs Jane Ngigi, says that aflatoxins cannot be found in soil as some people have claimed. "They are the products of two fungi, Aspergillus flavus and Aspergillus parasiticus and they need a substrate to grow. Poorly dried and stored maize provides an excellent growth medium for the fungi," she says.
The issue is that unless taken in large quantities, aflatoxins, like the rest of mycotoxins do not produce immediate symptoms but the long term consequences are devastating.
Medical researchers from the London School of Hygiene and Tropical Medicine, in collaboration with plant pathologists at the International Institute of Tropical Agriculture (IITA) in Benin, identify high exposure of aflatoxins as the main cause of impaired growth leading to stunting of children across Sub-Saharan Africa.
The researchers studied children aged nine months to five years in different climatic regions in Togo and Benin and found a striking association between exposure to aflatoxins and stunting. "Some infants are exposed at an early age and this continues throughout life," said Dr A. Hounsa of the London School of Hygiene and Tropical Medicine.
Besides, the study showed that growth faltering occurred at a time of change to solid food, when there is also additional hazards from a wide range of infections that include malaria, bilharzia, diarrhoea and respiratory infections. "Children partially breast-fed had lower exposure, confirming lower toxic levels in mother's milk than in weaning family foods, observed Prof C.P Wild, a principal researcher at IITA in Cotonou, Benin.
However, this is not the first time in the area that people have died after eating food contaminated with aflatoxins. In 1981, several families in Machakos district cooked and ate mouldy grain with high concentrations of fungal poisonous residues, scientifically known as mycotoxins. Mortality rate of those who feasted on the maize meal was about 65 per cent , according to a study conducted by the Ministry of Health.
So far, scientists have isolated 13 different types of aflatoxins that are produced in nature with aflatoxin B1, one of the culprits in the recent deaths, considered as the most poisonous. Other fungal species that produce aflatoxins in poorly stored food crops, apart from Aspergillus include Fusarium moniliforme and Penicillium cyclopium.
In such cases, too often, family 'food providers' are just keen to put food on the table with little regard for its quality. The problem is not restricted to rural areas where climatic conditions usually compromise food safety standards but fungal infected food products are being sold in supermarkets and other food outlets countrywide.
But whereas whole grains and other food crops may offer ideal conditions for contamination by aflatoxins, researchers have detected mycotoxin-producing moulds in processed foods such as popcorn, bread, cakes and varieties of soy breads sold in some supermarkets, retail grocery shops, budget hotels and restaurants.
According to Dr Siboe, most Kenyans are exposed to low and medium level doses of a wide spectrum of fungal poisoning through regular consumption of maize products. But on average, Kenyans eat maize products at the rate of 0.4 kg per person daily, hence even the lowest amount of exposure is cumulatively likely to be of severe health risk.
Mrs Ngige adds that Kenyans are all too familiar with the bitter taste of some of the ugali that we cook and says that this is a manifestation of a low level of aflatoxin. "Kenyans are slowly being exposed to low levels of afalatoxin poisoning that are asymptomatic and it is only when we reach crisis levels that kill we start to react," says the expert.
The different types of fungal poisonous substances isolated from the commercial maize products being sold in Nairobi and elsewhere in the country suggest many people and livestock are at risk of mycotoxin poisoning. In addition to eating the ugali of sub-standard maize flour available in the market, most Kenyans are exposed to aflatoxin by drinking busaa which is prepared from mouldy maize flour and millet.
Besides, maize is a major component in livestock and poultry feeds, and therefore there is indirect human exposure through consumption of animal products that contain fungal poisonous residues. Available studies show that such gradual ingestion of highly toxic substances might not result to immediate death but could slowly damage body organs, especially the liver where the aflatoxins are metabolised.
Aflatoxins are associated with liver cancer, suppression of the body's immune response, infertility among men, mental disorders and nutritional deficiencies. According to World Bank researchers, aflatoxin exposure is leading to reduced life expectancy in many countries of Sub-Saharan Africa.
Other health disorders linked to mycotoxin poisoning include liver cirrhosis, cancer of the throat and slow damage of body vital organs such as the liver, kidneys, heart and pancreas.
Taking into account that the shelf life of maize flour has a direct influence on the level of contamination by the moulds, there is need to undertake mycotoxin control programmes which would ultimately result in economic gains and reduce health risks. The situation calls for enactment of a comprehensive food safety policy on handling of grains through harvesting, drying, storage, post-harvest processing and marketing.
Food safety professionals have called on governments across Sub-Saharan Africa to advise farmers on merits of early harvesting as a means to reducing the risk of aflatoxin contamination. However, this pratice should be accompanied by modern rapid drying techniques as well as the use of improved storage facilities. However, tested traditional methods of protecting maize such as smoking should be re-introduced in rural areas.
But of immediate concern, Kenya Bureau of Standards must ensure that companies dealing with processing of grains and other food crops adhere to Food and Agriculture Organisation ( FAO) standards on moisture content of grains to be put into the market. The time has come for the government to take responsibility to stop the man's favourite diet from sending him and his family to an early grave.
