Former Vice-President Prof. Yemi Osinbajo has raised fresh concerns over the use of potentially dangerous chemicals to ripen and preserve fruits and vegetables in Nigeria, calling for stronger regulation, better enforcement and greater public awareness across the country’s food supply chain.
Osinbajo said consumers should not assume that fruits and vegetables are safe simply because they look fresh or because a drink is described as natural.
Speaking at the Open Day for Gardeners’ Seminar held in Lagos with the theme “Leaving the Earth Better Than We Found It,” the former vice-president linked food safety with wider questions of environmental stewardship, responsible agriculture and protection of future generations.
His intervention adds to longstanding concerns among regulators and public-health experts over pesticide residues and the unauthorised use of chemicals in the production, handling and preservation of food.
Osinbajo illustrated his concern with a personal experience involving his wife, Dolapo Osinbajo.
According to him, she had developed a habit of drinking freshly squeezed orange juice after giving up carbonated drinks years earlier.
However, she later began experiencing unusual headaches.
After reviewing other aspects of her diet without identifying an obvious cause, Osinbajo said a batch of the freshly squeezed juice was sent for laboratory testing and reportedly returned a result indicating that it was not fit for human consumption.
The account was presented as an example of why consumers should pay greater attention to what may happen to food between the farm and the dining table.
However, the speech did not identify the specific contaminant detected in the juice or establish that a particular fruit-ripening chemical caused the reported headaches. The broader public-health issue raised by Osinbajo is therefore more significant than drawing conclusions from the individual case.
His warning was simple: food that appears healthy or natural may still have been exposed to inappropriate chemicals during production, transportation, ripening or preservation.
A major focus of Osinbajo’s speech was the use of calcium carbide to artificially ripen fruits.
He said the chemical was sometimes used to make bananas, mangoes, pawpaws, tomatoes and other produce change colour quickly, giving consumers the impression that they had ripened naturally.
A peer-reviewed 2024 study involving consumers and fruit sellers in Ado-Ekiti, Ekiti State, found that 10 of the 20 fruit sellers surveyed reported using calcium carbide as one of their ripening methods. The researchers also found generally poor awareness among sellers about the potential health implications associated with the chemical.
The relatively small number of traders in that part of the study means the findings should not be treated as proof that half of all Nigerian fruit sellers use calcium carbide. Nevertheless, they provide evidence that the practice exists and warrants regulatory attention.
Osinbajo also referred to another study which, according to him, found calcium carbide use among 25 per cent of fruit sellers surveyed.
The former vice-president also cited a 2023 study involving 50 fruit and vegetable retailers in Lagos.
The research found that 22 respondents said they used chemicals to preserve produce.
That represents 44 per cent of those surveyed.
The Lagos study identified substances reportedly used by some traders including Gammalin-20, Sniper, aluminium phosphide, DDT, carbide and brodifacoum.
The findings are concerning because some of these substances have purposes entirely different from direct food preservation and may pose risks when misused.
DDT, for example, appears on Nigeria’s list of banned hazardous chemicals and pesticides under environmental regulations.
Brodifacoum is commonly used as a rodenticide, while aluminium phosphide is a fumigant that requires strict controls because of its toxicity.
The Lagos research, like the Ado-Ekiti study, involved a limited sample and cannot alone establish how widespread such practices are nationwide.
What it does show, however, is that inappropriate chemical handling within parts of the food supply chain is more than a hypothetical concern.
Osinbajo’s intervention comes against a history of regulatory warnings over chemically ripened fruits.
In February 2025, the National Agency for Food and Drug Administration and Control, NAFDAC, again warned fruit sellers against using calcium carbide for commercial fruit ripening.
The agency urged traders to stop the practice and intensified public awareness efforts around the dangers associated with inappropriate chemical treatment of produce.
NAFDAC’s 2025 Food Hygiene Regulations also require raw materials used in food production to come from identifiable sources, remain free of contamination and be handled, stored and transported under conditions that protect their safety and quality.
The challenge highlighted by Osinbajo is enforcement across a vast and highly decentralised food system involving farmers, transporters, wholesalers, retailers and informal markets.
The World Health Organization notes that pesticides have an important role in protecting crops and supporting food production, but they are potentially toxic to humans and must be properly regulated.
Health risks depend on the particular chemical, the amount involved and the level and route of exposure.
For this reason, international food-safety systems establish maximum residue limits designed to ensure that pesticides used correctly do not expose consumers to unacceptable levels.
The issue is not that every pesticide used in farming automatically makes food unsafe. Modern agriculture depends on authorised crop-protection products when they are correctly applied.
The greater concern is misuse, including application of banned products, excessive quantities, failure to observe required waiting periods or use of chemicals that were never intended for direct treatment of food.
That is where Osinbajo’s warning has broader implications for Nigerian consumers.
Most shoppers have little information about what happened to a tomato, mango, banana or orange before it reached the market.
Osinbajo called for stronger regulation and more effective enforcement of existing food-safety rules.
He also urged government agencies to improve public education while helping farmers and traders understand safer methods of preserving and ripening produce.
The issue illustrates the need to treat food safety as an entire supply-chain responsibility.
Regulation at the final point of sale may be insufficient if unsafe practices have already occurred on farms, in warehouses or during transportation.
Better surveillance, testing, traceability and enforcement could help authorities identify unsafe practices earlier.
Regular market inspections and laboratory monitoring are also important because appearance alone cannot determine whether food contains unsafe chemical residues.
Internationally, WHO and the Food and Agriculture Organization continue to evaluate pesticide residues and recommend safety limits through the Joint FAO/WHO Meeting on Pesticide Residues. The latest work continues to assess toxicology, residue behaviour and dietary exposure to support national and international food-safety standards.
Osinbajo argued that government regulation alone would not solve the problem.
He encouraged Nigerians to become more active in their communities, report suspicious practices, and ask questions about how food is produced and handled.
Consumers can also reduce some food-related hazards by thoroughly washing fruits and vegetables.
WHO advises washing or peeling produce where appropriate as one way of reducing exposure to some pesticide residues as well as microbial contamination.
Washing, however, should not be regarded as a guarantee against every hazardous substance or unsafe farming practice. Effective prevention must begin before produce reaches consumers.
Although food preservation dominated the final section of Osinbajo’s address, his wider message went beyond what Nigerians eat.
He called for greater protection of trees, land, natural resources and agricultural diversity.
The former vice-president argued that environmental appreciation must translate into stewardship and ultimately advocacy.
He urged citizens to support tree planting and forest protection and warned against decisions capable of compromising natural resources for future generations.
He also spoke about preserving seed diversity and ensuring that farmers have reasonable access to the seeds required to sustain agriculture.
These arguments fit the overall theme of the gardeners’ seminar, which focused on leaving the environment in better condition for the next generation.
The message is particularly relevant as Nigeria faces interconnected challenges involving food security, climate change, declining agricultural productivity and pressure on natural resources.
Food safety rarely receives the same attention as food prices or food shortages, but all three issues are connected.
Making more food available is not enough if consumers cannot be confident that what reaches their tables has been safely produced and handled.
For households, unsafe produce can translate into preventable health risks.
For farmers and legitimate food businesses, poor practices by some operators can damage public trust and threaten market opportunities.
Nigeria also has ambitions to increase agricultural exports. Meeting recognised food-safety and pesticide-residue standards is therefore important not only for domestic health but also for international trade.
Osinbajo’s message ultimately raises a broader question: who is responsible for what happens to food between the farm and the table?
The answer involves government regulators, farmers, traders, food processors, researchers and consumers.
The former vice-president’s call is therefore not simply for Nigerians to fear fresh produce. Fruits and vegetables remain important components of healthy diets.
Rather, the issue is ensuring that foods promoted as healthy are produced, preserved and sold under conditions that make them genuinely safe.
As Osinbajo argued, protecting the environment and safeguarding the food supply are ultimately part of the same responsibility: preserving the resources on which present and future generations depend.
