10 Unsafe Food Processing Practices in Nigeria

Author: Sifon Nsubong, Registered Nurse (RN)

Medical Reviewer: Azuka Chinweokwu Ezeike, MBBS, FWACS, FMCOG, MSc (PH)

Highlights.

• Every day, people provide food to feed themselves and their families using different food processing practices
• Food processing has to do with the way food is changed from its natural or raw form to make it digestible and safer.
• Food processing includes practices like ripening of fruits with calcium carbide, and frying groundnuts with excess salt. While these methods can improve taste, and shelf life, improper methods can reduce nutrition and pose health risks.
• Traditional methods such drying, salting, smoking, and fermentation are not automatically unsafe, risk depends of hygiene water quality, raw materials, and storage
• Consumers can reduce risks by using safer processing methods by cooking foods properly, limiting over- charring or over-smoking food, and limiting the addition of excess salt and sugar.

Introduction

Every day, people process food in order to feed themselves and families using different processing practices, such as freezing, drying, milling, canning, mixing, or adding too much salt, sugar, fat or additives [1].

Recently, former vice president Prof. Yemi Osinbajo raised concerns about food safety involving his wife’s freshly squeezed orange juice. According to him, his wife experienced frequent headaches after making fresh orange juice part of her daily routine; a sample of the juice was later sent for laboratory testing and reportedly found to be “not fit for human consumption’’ 

He linked the concern to chemicals and pesticides that may be used on fruits and vegetables, including calcium carbide, which he said is sometimes used to speed up fruit ripening.

Access to a sufficient amount of safe and nutritious food is key to sustaining life and promoting good health. Unsafe food contaminated with harmful bacteria, viruses, parasites, or chemical substances can cause more than 200 different diseases ranging from diarrhoea to cancers; they result in vicious cycles of disease and malnutrition, particularly affecting young children, older people and the sick. [2]

In this article, we will discuss what food processing means and the different food processing practices that may put our health at risk

What Does Food Processing Mean?

Food processing is defined as any procedure that alters food from its natural state, such as freezing, drying, milling, canning, mixing or adding salt, sugar fat or additives. [1]

It also has to do with the use of various techniques to transform raw agricultural produce into food products for human consumption. Processing can improve safety, preserve food, extend shelf life, and influence the nutritional, physical, and sensory properties of food.[3]

Why Should We be Concerned About How Our Food is Processed or Prepared?

The way a particular food is prepared matters because these practices can affect food safety, nutritional value, and also expose one to harmful substances. In 2021, 1 in 9 people got ill from eating unsafe food.

The World Health Organisation stated that food can be contaminated at any point along the food chain, and improperly or unhygienically prepared or handled food is an important cause of foodborne illness. [4],[5]

10 Food Processing and Preparation Practices You Should Be Concerned About.

Here are 10 different food processing and preparation practices you should be concerned about.

1. Using Calcium Carbide To Ripen Fruits.

Fruits naturally ripen through complex physiological processes regulated by several plant hormones,withethylene playing the central role.Calcium Carbide (CaC2) has sometimes been used as an artificial ripening agent because it reacts with moisture to release acetylene gas, which can mimic the effects of ethylene and speed up ripening. [6]

This practice may make fruits such as bananas, mangoes, and plantain appear ripe more quickly, allowing them to reach the market sooner.

Commercial calcium carbide may contain impurities, including arsenic and other potentially toxic substances. When used to to forcefully ripen fruits  they lose their original nutrients and become poison, exposing consumers to cancer and other related killer diseases

According to the National Agency for Food and Drugs Administration and Control (NAFDAC), calcium carbide poses serious health risks to consumers .

2. Frying Groundnut With Excessive Salt. 

Groundnuts are nutritious food, providing protein, healthy fats, fibre, vitamins, and minerals.  Groundnuts can be roasted or fried and then heavily salted to improve their flavour and make them more appealing as a snack.Groundnuts can be fried with salt, but adding in excess is concerning; our bodies need some sodium, but consuming too much can increase blood pressure. According to the World Health Organisation, over time, consistently high sodium intake can increase the risk of cardiovascular diseases such as heart disease and stroke.

It is recommended that adults consume less than 5 grams of salt per day, equivalent to less than 2grams of sodium. This amount includes salt from all foods consumed throughout the day, not just the salt added to groundnuts.You do not have to stop eating groundnuts; instead, choose unsalted or lightly salted groundnuts, and use herbs and spices to add flavour without relying heavily on salt

3. Reusing Cooking Oil Repeatedly

Have you ever fried something and kept the leftover oil to use again? For many households and food vendors, reusing cooking oil can seem practical; it saves money and reduces waste. But how often is this actually happening?

Reusing cooking oil entails heating oil, allowing it to cool, storing it, and then heating it again for another cooking or frying process.In 2025, a study showed that 80% of respondents in 172 families comprising 672 family members reported reusing leftover cooking oil after frying.

When oil is repeatedly exposed to high temperatures, oxygen, moisture, and food particles, it undergoes chemical changes, including oxidation. Repeated oil can increase the formation of oxidation products, this oxidized compounds promotes chronic exposure to hypertension, metabolic disease, cardiovascular disease, and possibly cancer.

 Repeated frying of oil promotes lipid peroxidation and fatty acid profile changes that predisposes consumers to increased health risk. The oil may become darker, thicker, develop an unpleasant smell or taste, and lose some of its desirable properties. 

4. Poor Hygiene and Use of Unsafe water

Poor hygiene during food processing occurs when hand utensils, equipment water, or food contact surfaces are not kept clean and safe. This includes using dirty or contaminated water to cook meals, or clean utensils and preparation surfaces. Water plays a fundamental role in food safety and production. However, using water that is contaminated with germs, dirt, sewage, chemicals, or other pollutants to wash and cook meals, or clean cooking utensils poses a potential health risk because harmful microorganisms and other contaminants in the water can enter food during preparation.

 Contaminated water may contain bacteria, viruses, and parasites capable of causing diarrhoea, cholera, dysentery, dehydration, typhoid, and other gastrointestinal infections. 

These practices can introduce harmful microorganisms into food and increase the risk of foodborne illness. WHO recommends maintaining 

• Cleanliness
• Separating raw and cooked foods
• Using safe water and raw materials, and cooking food thoroughly as key measures for preventing food contamination.

5. Cooking of meat with Parcacetamol (Acetaminophen)

Meat is the edible portion of domestic and wild animals, it is rich in proteins, essential amino acids, and fats.Paracetamol (Acetaminophen) is an over the counter medicine used to reduce fever and mild to moderate pain. It is one of the most prescribed analgesic drugs globally.Paracetamol must never be used to soften or cook meat. It is a medicine for treating pain and fever, not a food ingredient or meat tenderizer.

 According to Nigeria’s food and drug regulator, NAFDAC, using paracetamol in food preparation is dangerous.When paracetamol is exposed  to cooking conditions, it can break down and form toxic substances including 4-aminophenol. These substances may damage the liver and kidneys.

6. Using Excessive Food Additives and Preservatives

Food additives are chemicals that are added to food to keep it from spoiling, as well to improve its colour or taste and extend shelf life, but problems can occur when added in excess without following recommended safety limits.

Food additives can be derived from plants, animals, or minerals, or they can be chemically synthesised. There are several food additives used, all of which are designed to do a specific job. Excessive consumption or improper use may increase exposure beyond recommended levels and may impose on our health.

7. Over-smoking or Over-charring Food

Over-smoking or over-charring involves exposing food, particularly meat, fish or poultry, to excessive smoke, flames, or very high temperatures for prolonged periods, causing the surface to become heavily blackened or burnt. This can occur during open-fire cooking, charcoal grilling, barbecuing, roasting, or traditional smoking methods.

During high-temperature cooking, especially when fat and meat juices drip onto flames, chemical compounds such as polycyclic aromatic hydrocarbons( PAHs) and Heterocyclic mines(HCAs) can form and accumulate on the food. These substances can damage cells and DNA, affects the liver, lead to increased risk of cancer. T

he WHO/FAO joint expert committee on food additives (JECFA) recommends reducing PAH contamination by avoiding direct contact between food and flames and by reducing contamination during smoking and drying processes.

8. Improper Fermentation of Food

Fermentation is normally a useful food-processing method in which beneficial microorganisms, such as certain bacteria, yeasts, and molds, convert components or food into acids,gases, or alcohol.

Improper fermentation occurs when food is fermented under poorly controlled or unhygienic conditions. This may include using contaminated raw materials or water, unclean equipment, unsuitable fermentation temperatures, inadequate fermentation time, or uncontrolled fermentation by unwanted microorganisms.

Recent Nigerian media reports and community accounts have raised concerns that some processors may use detergent or soap when soaking or washing cassava, reportedly to hasten fermentation or improve the appearance of the finished products.

Detergents are household cleaning products, not food processing ingredients and should never be added to cassava, fufu, or any other food. They can leave chemical residues that may irritate the mouth, stomach, and intestines and may pose additional health risk with repeated or substantial exposure.

9. Adding Dyes to Palm Oil

Adding unapproved dyes to palm oil to make it look redder or fresher is food adulteration, The U.S. FDA describes economically motivated adulteration as intentionally adding something to make food better or more valuable, or substituting a valuable ingredient for financial gain.

Natural pail oil gets its red-orange colour from carotenoids in the f=palm fruit. There is also a recent report according to Lagos State Consumer Protection Agency who identified the use of potentially carcinogenic sudan and azo dyes to alter palm-oil colour as an emerging adulteration risk.

10. Washing Vegetables and Fruits with Detergent or Bleach

Detergent and bleach are made to clean surfaces, not to be eaten. Washing Vegetables and fruits with detergent or bleach is a recognized harmful food-handling practice because it can leave toxic chemical residues on food and make people sick.Some fruits and vegetables have tiny holes and can absorb soap, detergent, or bleach residues, which may change their safety and taste.

What Harm can Unsafe Food Pocessing Practices Cause?

Harmful food-processing and handling practices can turn nutritious food into sources of illness, those practices can introduce harmful substances, encourage the growth of disease-causing micro-organism, or reduce the nutritional quality of food.

Immediate health effects

• Diarrhoea: Contaminated food can cause loose or watery stools, often due to bacteria, viruses, parasites, or toxins. Severe or persistent diarrhoea requires medical attention, especially in young children, older adults, pregnant women, and people with weakened immunity.[4] 
• Cholera: Cholera is an acute diarrheal infection caused by consuming food or water contaminated with the bacterium Vibro cholerae. It may lead to rapid fluid loss.
• Nausea and Vomiting: These are common signs of foodborne illness and may result from germs, toxins, chemical contamination, or spoiled food.
• Abdominal pain or cramps: These are sudden tightening, squeezing, or painful spasms in the stomach or intestines. They are common immediate effects of eating contaminated spoiled, improperly stored or poorly cooked food

Long-term health effects

• High blood pressure: Regular consumption of very salty foods can raise blood pressure. WHO recommends limiting salt intake to less than 5 g per day for adults.
• Heart disease and stroke: High salt intake contributes to hypertension, which raises the risk of heart disease and stroke. Diets high in saturated fats and industrial trans fats also contribute to cardiovascular risk. 
• Tooth decay: Frequent intake of foods and drinks high in free sugars increases the risk of dental caries, also called tooth decay. 
• Overweight and obesity: Regular intake of energy-dense foods high in sugar and unhealthy fats can lead to unhealthy weight gain. Overweight and obesity raise the risk of cardiovascular disease and type 2 diabetes. 
• Type 2 diabetes: Long-term unhealthy dietary patterns, particularly when they contribute to overweight and obesity, increase the risk of type 2 diabetes.
• Liver damage: Certain food contaminants can harm the liver. For example, long-term exposure to aflatoxin B1, a toxin produced by mold in poorly stored foods such as grains and groundnuts can cause liver cancer, especially in people living with hepatitis B infection
• Kidney and nervous-system damage: Metals such as lead, arsenic, mercury, and cadmium can contaminate food and may cause serious long-term health effects. Depending on the substance and exposure, they can affect the kidneys, brain and nervous system, blood, and cardiovascular system.

Does Traditional or Local Food Processing Always Mean the Food Is Unsafe?

Traditional or local food processing does not automatically make food unsafe. Many traditional methods such as fermentation, drying, smoking, roasting, and salting can preserve food and when properly controlled, can reduce spoilage and some harmful microorganisms. The Food and Agriculture Organization of the United Nations (FAO) notes that dying, salting, smoking, and fermentation are established traditional preservation methods. The safety of food depends on proper hygiene, safe water, good quality raw materials, adequate processing, and appropriate storage. 

What Can Food Vendors and Food Handlers Do Differently?

Food vendors and food handlers can reduce the risk associated with unsafe food processing by adopting simple, consistent food-safety practices. Food vendors and handlers should:

• Wash hands properly before handling food
• Separate raw and cooked foods to prevent cross-contamination
• Cook food thoroughly, especially meat, poultry, seafood, and eggs
• Keep meals at safe temperatures and refrigerate perishable foods promptly
• Clean and sanitise utensils, equipment, and food contact surfaces regularly.
• Protect food from insects, rodents, dust, and other contaminants
• Avoid using spoilt or unsafe ingredients
• Receive regular food safety training so that safe handling practices become routine
• Follow tested fermentation methods appropriate for the particular food.
• Store the finished fermented product under the recommended conditions.
• Use safe water and ingredients
• Discard food showing unusual mould growth, off odours, abnormal colours, or other signs of spoilage rather than trying to salvage it.
• Cook with little or no added sodium/salt
• Reduce excess amounts of sugar and additives.
• Use fresh oil and avoid repeated reuse.
• Use proper fermentation methods
• Not add dye to palm oil or other foods unless the specific colour additive is approved for that food and used at the legal level
• Not use industrial dyes or unknown colourants to make products appear fresher, redder, or more attractive. 
• Use only approved food additives and preservatives, and use them only at Cook at moderate heat and stop when the groundnuts are lightly golden, not burnt.
• Allow the nuts to cool before storing them in a clean, dry, airtight container.
• Check packaged products for their sodium content and avoid heavily salted varieties.

What Can Consumers Do to Protect themselves?

Consumers can reduce the risk of foodborne illness by taking the following precautions:

• Buy food from clean and reputable vendors who maintain good hygiene
• Choose packaged foods with a clear label showing the manufacturer or importer ingredient list, batch, or lot number, production date, expiry or best-before date, storage instructions, and relevant regulatory information.
• For packaged regulated products in Nigeria, consumers can use NAFDAC’s verification tools, where applicable, rather than relying solely on verbal assurances from sellers. 
• Wash fruits and vegetables thoroughly with safe, clean water before eating or preparing them
• Keep raw or cooked foods separate when shopping, transporting, and storing food at home.
• Cook food thoroughly, particularly meat, poultry, seafood, and eggs
• Store perishable foods properly and refrigerate them promptly
• Reheat leftover food thoroughly before eating.
• Avoid intake of food that has been exposed to dust, insects, or other contaminants for long periods.
• Food safety is everyone’s business; consumers can reasonably ask vendors how food was prepared, stored, and transported before buying.
• Inspect the appearance of the fruits (Unnaturally bright, uniform colour)
• Be cautious if fruit has a little natural aroma or a faint chemical/garlicky odour,
• Avoid fruits that rot or spoil unusually fast
• Avoid fruits that are soft outside but hard/raw inside, less sweet, or has a bitter/chemical aftertaste

Conclusion

Food processing and preparation practices are very essential for making food safe, nutritious, and enjoyable, but unsafe practices can expose people to biological and chemical hazards. However, food vendors, food handlers, and consumers also have an important role to play by choosing hygienically prepared food, checking food quality and expiry dates, storing food properly, and avoiding foods that show clear signs of spoilage or contamination.By improving food-processing practices from production to consumption, many preventable foodborne illnesses and related health risks can be reduced, helping to ensure that the food we eat is not only available but also safe and healthy.

References

1. Poti JM, Mendez MA, Ng SW, Popkin BM. Is the degree of food processing and convenience linked with the nutritional quality of foods purchased by US households?1234. Am J Clin Nutr. 2015 Jun;101(6):1251–62. PubMed PMID: 25948666; PubMed Central PMCID: PMC4441809. Available from: doi:10.3945/ajcn.114.100925 

2. Food and Agricultural Organization of the United Nations. Basic facts about food preparation [Internet]. [cited 2026 Sep 17]. Available from: https://www.fao.org/4/y5113e/y5113e04.htm

3. Knorr D, M.A Augustin. ScienceDirect [Internet]. [cited 2026 Sep 22]. Food processing needs, advantages and misconceptions. Available from: http://ww547.sciencedirect.com/?tkn=19vnMT3S 

4. World Health Organization. Foodsafety [Internet]. [cited 2026 Sep 22]. Available from:  https://www.who.int/news-room/fact-sheets/detail/food-safety

5. World Health Organization. [Guidance] [Internet]. [cited guidance Sep 17].Guidance on safe and healthy food. Available from: https://www.who.int/tools/compendium-on-health-and-environment/safe-and-healthy-food

6. Mode AM, Magaji UF, Babatunde MS, Dandare A, Dabai IA, Dandare SU. Effects of Chemical Ripening With Calcium Carbide on Nutritional Composition, Antioxidant Capacity and Heavy Metal Accumulation in Climacteric Fruits. Int J Food Sci. 2026 Apr 30;2026:7226409. PubMed PMID: 42079360; PubMed Central PMCID: PMC13129937. Available from: doi:10.1155/ijfo/7226409

Disclaimer:
The information provided on this website is for general educational and informational purposes only. It is not intended to replace professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

Published September 28, 2026