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WORLD HEALTH DAY 2025: FRESH BUT RISKY – ARE YOUR VEGGIES SAFE FROM WASTEWATER URBAN AGRICULTURE?
By Dr. Prince Antwi-Agyei, Environmental Health Researcher, UENR – Ghana
In the heart of Accra, where land is scarce and water even scarcer, urban farming is a lifeline. On the fringes of drains and in vacant plots and undeveloped lands, urban farmers grow vibrant leafy vegetables – lettuce, cabbage, spring onions – destined for local markets, street food stalls, and family kitchens. This form of urban agriculture supports livelihoods and contributes to food security. But beneath the green leaves lies a risk that many consumers know little about: the widespread use of untreated wastewater to irrigate these crops.
In a city where clean water for irrigation is costly or unavailable, wastewater from open drains becomes the default. Rich in nutrients, this water helps crops grow faster and reduces the need for chemical fertilizers. But along with nutrients come disease-causing organisms, invisible to the eye yet potent enough to make entire communities sick. This hidden danger was the focus of this research, which set out to follow produce from farm to fork (farmgate, markets, hotels and restaurants, and street vending sites) and assess how exposure to contaminated vegetables affects human health in Accra. My team and I tested for the water used for irrigation, the soil that nurtured the crops, the hands that harvested and prepared them, and the final product eaten by consumers.
We collected over 800 samples from irrigation water, farm soil, fresh produce, market vegetables, and street-vended salads. The results were alarming. The irrigation water used in urban farming had an average E. coli concentration of 5.0 log10 E. coli/100 ml, far exceeding international safety guidelines. Even at the farm level, lettuce showed contamination, with an average of 3.3 log10 E. coli per gram. By the time these vegetables reached street food vendors, E. coli levels had increased to 4.2 log10 per gram, confirming that contamination continues through the supply chain. In fact, 98% of ready-to-eat salad samples from street food vendors were found to be positive for E. coli, followed by market lettuce (97%), farm lettuce (96%), market cabbage (89%), and restaurant salads (80%).
But bacteria weren’t the only concern. We also detected norovirus and adenovirus – common viral culprits of diarrhoea and gastroenteritis in several samples. These pathogens can cause serious illness, particularly among children and vulnerable populations.
To understand how people interact with these contaminated foods, we observed over 700 individuals, including farmers, traders, vendors, and consumers. Farmers often worked without gloves or protective clothing, walking barefoot through wet fields and handling soil and wastewater directly. At markets, vegetables were often rinsed in the same bowl of water multiple times or not at all and were rarely rewashed before sale – observations showed that washed water for produce was used without changing it for an average of 22 minutes and the washed water was always contaminated. Again, the storage duration and temperature were found to influence the quality of produce sold on the markets . On the streets, vendors frequently handled money and food without washing their hands in between. The high concentrations of street food salad in this study could also be attributed to the poor sanitation (e.g. dust, refuse) and hygiene practices (e.g. uncovered salad, use of chopping board for multiple purposes) at the vending sites. The cut or sliced nature of the prepared salad also facilitated the growth of microorganisms or increased their persistence. At hotels and restaurants, the source of raw produce and operating with a valid hygiene permit were also found to be associated with the quality of salad sold at these places.
Interestingly, in interviews, over 70% of vendors and consumers acknowledged the risk of illness, yet few reported changing their behaviour. Not surprisingly, the study found that consumers did not prioritize health indicators when buying produce from vendors. Instead, they were motivated by factors such as taste, friendship, cost, convenience, and the freshness of the produce. In fact, only 2% of consumers reported choosing a vendor based on food safety considerations.
Despite the widespread contamination, this story isn’t one of hopelessness – it’s one of opportunity. There are simple and effective ways to make produce safer. Washing vegetables thoroughly with clean water, salt, and even better, using a mild disinfectant like vinegar, significantly reduces harmful microbes. Cooking vegetables is another easy step to reduce risk. Choosing vendors who maintain good hygiene – washing hands, using clean water, and storing food properly can make a real difference.
Beyond individual actions, policy change is critical. Authorities must enforce food safety regulations, especially among informal vendors. Municipalities should promote low-cost water treatment solutions for urban agriculture and support training programs on hygiene for farmers and street vendors alike. Investments in public awareness – especially through schools, markets, and health centres can also foster behaviour change.
The implications go beyond health. Urban agriculture is key to food security and employment in Ghana and other parts of sub-Saharan Africa. Making it safer strengthens both individual well-being and the economy and urban resilience. What’s needed now is collaboration between governments, researchers, communities, and consumers.
This research serves as a wake-up call. Urban-grown vegetables nourish our cities, but unless we address the risks hidden in wastewater and poor hygiene practices, we risk turning food into a source of illness. Safe food is not a luxury; it is a right. With the right steps, it is a goal well within our reach.
As we celebrate World Health Day today, let’s commit to safer food from farm to fork – because protecting our health starts with how we grow, handle, and eat what’s on our plate. Let’s work together to ensure that the food nourishing our cities doesn’t make us sick.