Germs in a bowl, Nairobi’s deadly sukuma wiki

Almost all the three million mouths residing in Nairobi today, and thousands of local and foreign visitors to the fastest growing city in East Africa, eat sukuma wiki (kales) on a regular basis.

And the government estimates that, in the next decade, the number of people residing in the city will have reached 25 million — quite a mouth-watering market for practising and aspiring farmers.

Currently, it is estimated that there are about 3,700 farmers within a 20-kilometre radius of Nairobi who practise irrigation agriculture, with about half of them using poor quality water.

This water, reports a new research by the universities of Nairobi and Sweden, contains the full spectrum of disease-causing organisms found in the urban population, many of which can survive for several weeks when discharged onto the fields

Sukuma wiki, which for years has been the perfect accompaniment for one of Kenya’s most popular culinary offers — a plateful of ugali — is now one of the most consumed leafy vegetables in the city.

No longer the staple for those who cannot afford meat, and because of a spirited campaign by nutritionists who preach “the greener it is, the better”, kales are now a major commercial crop grown on small plots on Nairobi’s road sides, and even along the capital’s sewer lines.

For example, in Athi River, home to several manufacturing industries — which, of late, include a meat processing plant, wine distilleries and skin and hide processing plants — that discharge their wastes into the River Athi, a number of farmers use this untreated effluent water to grow kales. And the sad story is repeated across the city and its environs.

The result of this stomach-churning version of urban agriculture, says the report published in the current issue of the East African Medical Journal, is that quite a considerable number of Nairobi residents are eating highly contaminated sukuma wiki, the product of poor quality water and unhygienic handling and transportation to the market.

Researchers sampled kales grown in Athi River, Ngong and Wangige and those sold in markets in Kawangware, Kangemi and Githurai, and the results from all these areas were the same: the vegetables on sale in the city are a major health hazard.

And it does not matter whether you get your daily fix of the vegetable from a roadside hawker or a supermarket or other high-end specialty stores, the risks are the same.

The researchers tested the kales for coliforms, a broad class of bacteria found in the environment, including in human and animal waste, and returned a positive result.

Other organisms tested for was E.coli, a group of bacteria that causes stomach upsets, diarrhoea, urinary and respiratory ailments; and salmonella bacterium, which can cause serious food poisoning.

Sukuma wiki from the open markets of Kangemi and Kawangware and supermarkets that source the vegetable from the same suppliers were found to have higher disease-causing organisms associated with faecal matter than those still in farms, which points to the possibility of more contamination in transit.

“Faecal coliforms in water used on farms for irrigation and in the markets for washing the vegetables exceeded levels recommended by the World Health Organisation,” says the study.

Contamination by faeces or urine, the study says, originated from animals or human waste disposed into water sources used for irrigation and also from wrong use of manure. In some of Nairobi’s vegetable-growing hubs, farmers were found to be using liquid slurry from sewers which, apart from providing water to the crops, is also regarded to be “rich in nutrients”.

In Kibera last week, we found Khadija Shamim watering her sukuma wiki, planted in a soil-filled sack at her doorstep, with water from a highly suspect source. The vegetables, planted two weeks ago, are almost ready for harvesting, but this speedy growth and the lush, inviting leafs are now the focus of scientific wrath.

Khadija, however, is not amused.

“We fetch our water from an open borehole in the neighbourhood,” she told us. “We know that a number of people here use plastic containers to relieve themselves at night and probably wash them in the same well in the morning, but we still rely on the water for our vegetables to flourish.

We have, however, devised a plan to ensure the safety and hygiene of the vegetables by watering the stems and roots of the crop rather than the leaves.”

That plan, however, may not be working. An earlier study by both the UoN and Kenyatta University, which was carried out in Khadiha’s Kibera neighbourhood and Maili Saba along the Ngong River, a tributary of the Nairobi River Basin, found kales in the area to be heavily laced with heavy metals and germs.

“(These contaminants) were recorded mostly in the stem and leaves, (and) raise health concerns since the leaves are harvested for human consumption. As expected, the soils and the plant samples contained high bacterial and parasitic loads,” reported the study, published in the journal Tropical and Subtropical Agroecosystems

The quality of water used to irrigate the crops along the Ngong River was blamed for both the presence of germs and heavy metals. High levels of contamination with salmonella were also detected on samples collected from farms in, again, Wangige and the open market of Kawangware.

An earlier study on sukuma wiki by the same group in Nairobi had indicated the presence of heavy metals, pesticides and fertiliser residue in the samples.

At the same time, say the researchers, to keep the kales fresh and appealing, most retailers sprinkle or moisten them with unclean and sometimes polluted water.

Shamim says: “Majority of those who buy vegetables from me do not query where I get the water from. They are interested in the product and not the process that leads to its maturity.

“We make a killing; I sell five or six leaves for Sh10. This is a lot of money given that my only inputs are the seedlings that I purchase.”

Although big supermarkets have inspectorates that supervise contract farmers, the latter were found to be outsourcing some vegetables from other unpoliced farmers to meet the agreed quantities. “It therefore seems that post-harvest contamination is a major risk, in event of presence of disease causing bacteria.”

The study also documented possible contamination during transportation of the commodity. Most traders in Githurai and Kangemi transported the vegetables using open trucks, while in the former people carry them on their backs.

The City Council of Nairobi, through Public Health Officer Robert Ayisi, now says it will conduct investigations to verify the findings of the study.

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For farmers, the end justifies the means

Visits to the estates and slums highlighted in the report confirm the sad news: greedy farmers have taken to short cuts to produce this Kenyan piece of cuisine also known as ‘collard greens’.

In Kibera, for instance, sukuma wiki is either grown in earth-filled sacks, a small garden or besides a sewer that leads to the main Nairobi dam.

The farmers are aware of the hazardous methods used to irrigate the plants and even the location of their plantations, but do not seem to care.

“The consumer rarely asks where the vegetables come from,” says Khadija Shamim of Kibera. “My neighbour has a farm near the sewage trench and yet supplies supermarkets. It’s a win-win situation. As long as the vegetables are pest-free and their leaves are huge, you are in business.”

Kale farmers in Nairobi say that growing the commodity along sewer lines and dams relieves them of the burden of expensive fertilisers. And because they have invested little money in the process, they sell the commodity cheaply, which attracts a lot of customers, especially slum dwellers and other Kenyans suffering the effects of high inflation.

Other than sukuma wiki, other vegetables planted in these most unlikely of places include arrow roots, spinach, traditional vegetables, tomatoes and herbal medicine.

“The location of our shambas is good enough in the sense that you do not have to rely on the rainy season. I can harvest up to four times in a week and make a lot of money,” says Mary Mulinge, who owns a small piece of shamba near Nairobi Dam.

Mulinge is a vegetable vendor and supplies traders in Kangemi and Kawangware.

“Sometimes the prices of these commodities at Marikiti and Gikomba markets are too high, but because of our low production costs, we somehow remedy the price curve. Our only investment in the whole process, other than the initial seedlings that we buy, is weeding, which we do mechanically and at minimal or no cost,” she says.

Horticulturalists advise that sukuma wiki seedlings should be bought from known dealers who have sprayed them with insecticides. Pesticide spray is mandatory because the vegetables are prone to moth balls and black rots, while compost manure should only be applied a month before planting of the vegetables.