High levels of toxins in food causing damage

The news, buried in a small brief at a corner of the inside pages of the newspaper, elicited little reaction from the public. Maybe it was the shortness of the piece — all of 50 words — that led to this disinterest, or maybe it was the frequency with which such news is today reported in the national dailies. Either way, there was not hubris, no protests, no press conferences and releases. All was quiet, so eerily quiet.

“A university lecturer has raised alarm over contaminated maize being sold through informal channels,” the piece, in the Daily Nation towards the end of last month, started. “Prof Sheila Okoth of the University of Nairobi School of Biological Sciences said most food sold in local markets did not go through any quality control testing, posing health risks to consumers. She said the government had a duty to save Kenyans.”

That same week, several bags of contaminated maize were found to be unfit for human consumption in Thika. While that may sound too coincidental, it was, in fact, not. Cases of contaminated food on sale across the country have become so common in the past few years that, like the brief above, they rarely generate any national debate.

Unfit for consumption

In 2010, the government, through the Kenya Bureau of Standards, warned of high levels of maize contamination in Eastern and Coast provinces. A year later in 2011, the Centre for Disease Control and the Ministry of Public Health carried out research in 20 maize milling companies which revealed that 65 per cent of commercial maize meal contained unsafe levels of aflatoxins and, hence, was unfit for human consumption.

That same year, Sheila Sendeyo, then a reporter at Citizen TV, did a news feature about vegetables grown in certain parts of Nairobi and irrigated using sewage with high content of estate waste and factory effluent. While vegetables grown in such conditions are said to be greener and better-yielding, research has also shown that they contain harmful metal elements that we shall discuss in a moment.

The thing about food is that it is personal. Every lump that lies on your table, every slice that you hold in your hand, every crumb that you turn in your mouth, every bolus that goes down your gullet, and every drop of water that you take to push it down... is personal. It is personal as it is intimate, and it is intimate as it is crucial for your survival.

It is personal because from food you get energy. It is personal because from food you up your immune system. It is personal because from food springs your health.

Every tiny or large bit that you take as your food is personal because from that food cometh your life. That is why, when you read these reports in the papers, you need to be very concerned.

The enduring message throughout has been that the food on your plate may not be as safe as you think, but for purposes of this article we will study three key food elements on any Kenyan table. First is the national staple — maize — followed by two of its compatriots — beef and vegetables. At any given meal time in any part of the country, one of these will be served, so it is only right that we focus on them.

For maize and most cereals, contamination from aflatoxins is common. The bugs occur as a natural contaminant in maize but require a particular temperature and humidity to produce harmful toxins.

Dr Christine Bill, a researcher at the Kenya Medical Research Institute (Kemri) and specialist in the area of food storage and handling, explains that poor storage of grains leads to most of the spoilage. When maize is stored under moist conditions after inadequate drying or in plastic bags, those conditions promote the growth of mycotoxicogenic fungi (aflatoxins and fumonisin), which leads to spoilage.

Mycotoxin exposure in Kenya is high, though people do not know about it. Most breakfast cereals and sorghum, maize, and rice are affected. The outcome of this includes liver and oesophageal cancer and fast progression to HIV/Aids due to the immunosuppressive nature of mycotoxin.

Upon ingestion, aflatoxin poisoning is known to cause liver and/or kidney failure and, at times, liver cancer. When ingested in large quantities, the reaction is immediate. Yellowing of the eyes, diarrhoea, and death are possible within 48 hours. But when consumed in low quantities, the effects will be slow in showing.

Prof Okoth explains that tests conducted on rats in order to understand the effects of aflatoxin poisoning show inhibition of protein absorption, nervous dysfunction, and a weak immune system.

Heat-stable contaminants

“The problem is that the contaminants are heat-stable,” explains Prof Okoth. This means that they cannot be easily broken down by heat except at temperatures beyond 200C. Normal cooking, therefore, cannot destroy the toxins.”

The best way to limit contamination is by proper drying of maize to prevent the fungus from producing the toxins. This can be done through the construction of special silos where temperature control is possible. But once there is contamination, the only thing to do is to destroy the maize since even if it is fed to animals, it will still be dangerous as the toxins will be passed on via milk, eggs, and meat.

The beef and meat industry in Kenya is even harder to police. Concerns have been raised about the origins and handling of most meat sold around the country and every now and then Kenyans are treated to the tragicomedy of police officers chasing suspects in the donkey meat underworld.

Between 2010 and 2012, Dr Sam Kariuki, a scientist and researcher at Kemri, was part of a core team studying food safety in meat value chains across Kenya.

The study, whose findings were presented recently, was undertaken in Mombasa, Nairobi, Kisumu, Eastern, and other parts of the country and followed the meat chain from the farm to the fork. Their findings bear few good tidings.

From the farm, to the animal trader, to the slaughter house, to the delivery process, and finally to the handling of the final product, even the laziest germ will get on board. And they do, a lot.

Take chicken, for example. Farmers in the poultry business have a morbid fear of disease outbreaks. And that is for a good reason; when there is a poultry disease outbreak, the farmer most of the time loses the entire population. So, to prevent this, most have decided to increase their usage of poultry antibiotics to vaccinate their birds against the possible dangers.

But those farmers are not veterinary officers, so they end up abusing the antibiotics, which leads to the development of resistance against the drugs. Some bacteria like E. coli and Campylobacter have shown such resistance and can be passed on to humans.

In the course of their study, Dr Kariuki and his colleagues found after surveying several abattoirs in different parts of the country that beef contamination starts at the abattoirs (that is hoping that the animal being slaughtered was tested and clinically approved as being of sound health). This is due to the number of people handling the meat from this point (the more the number of handlers, the higher the risk of contamination) and the hygiene conditions of the abattoirs themselves.

After the slaughter comes the transportation from the abattoir to the butchery. Distribution and delivery accounts for a good percentage of contamination that occurs in most meat products. Challenges of proper equipment for transportation have led to contamination in cases where substandard containers are used or where trucks used for transporting other products are re-used without disinfection.

But the pinnacle of contamination is at the butchery, where one would assume that the meat will be safe. Here, there are two problems; the storage and the handling.

“If meat is not refrigerated, after 24 hours it becomes a culture medium, meaning it promotes the growth of bacteria. This mostly explains the difference in meat quality and safety standards in higher-class or upmarket areas compared to low-class butcheries,” says Dr Kariuki.

Salmonella poisoning and staphylococcus aureus poisoning, depending on the quantity of food and amount of bacterium per gramme, can lead to immediate symptoms like cramping of the abdomen, stomach upsets, and diarrhoea.

Dr Kariuki, who is the head of the Centre for Microbiology Research (CMR) at Kemri, says whereas most of the contamination that occurs in meat products can be cooked away as heat breaks down the micro-organisms, there are others like staphylococcus aureus that produce toxins which cannot be broken down by heat.

As for sewage vegetables, they may be greener and larger and look healthier, but real danger lurks within that attractiveness. The problem with sewage water, says Prof Okoth, is that during the process of water and nutrient absorption in plants through active transport, minerals are taken up alongside metal elements like cadmium, chromium, lead, and even mercury, which probably came in as factory effluent.

Since these metal elements cannot be broken down by heat, they accumulate in the body and since they are cancer-causing, lead to cell malfunctioning and eventually serious harm. Some of them accumulate in the kidneys, leading to renal problems.