A typical West African menu is not complete without a fermented food or drink, which are foods transformed by natural processes involving ‘friendly’ micro-organisms such as bacteria or yeast. These break down the sugars and other substances in the food, changing its taste and texture, and sometimes even preserving the food.
Some examples of fermented foods from the region are those made from African locust beans, such as iru (Nigeria), dawadawa (Ghana), netetu (Senegal) and afitin (Benin). Other products include okpehe (Nigeria), and Burkina Faso’s bikalga and soumbala.
Fermented foods are rich in proteins, dietary fibre, and essential minerals such as iron, calcium and potassium. Iru and other legume-based products provide essential amino acids and are a rich source of protein and fibre. Dawadawa contains antioxidants that help protect cells from oxidative damage (cell damage caused by stress).
Although many of these foods are used as condiments, they also serve as low-cost meat substitutes due to their high protein content and good taste.
The alkalinity of these fermented foods helps preserve them, as micro-organisms (which cause food to spoil) don’t grow easily in alkaline substances. Nonetheless, there are safety concerns with some of these foods. Risks can arise in the way they are prepared and the quality of the fermentation process.
Food safety risks
As a microbiologist, I have studied West African alkaline-fermented foods and highlighted several safety issues they present. I’ve also suggested ways to make these foods safer.
One safety concern is the risk of contamination by mycotoxins and bacteria related to poor hygiene. Mycotoxins are toxic substances produced by certain moulds that can contaminate crops during growth, harvest, storage or processing.
They are capable of causing diseases or even death in humans and other animals. The adverse health effects of mycotoxins range from acute poisoning to long-term effects such as immune deficiency and cancer.
Heavy exposure to aflatoxin, a type of mycotoxin, causes liver damage, jaundice, haemorrhage and oedema. Lower exposure to aflatoxin over a long time may cause immuno-suppression and cancer.
Unregulated traditional practices, which may involve unhygienic utensils and handling, can pose a threat to food safety by introducing bacteria able to survive alkaline conditions. In addition, fermented food products often use salt as a preservative. Consuming too much salt may adversely affect health, worsen conditions such as cardiovascular diseases, and increase the risk of stroke.
To minimise the safety risks of fermented foods, it is important to reduce the amount of salt and store foods properly. Grains and seeds should be inspected and any that look mouldy, discoloured or shrivelled should be discarded. Damage to grains before and during drying, and in storage, should be avoided.
Five approaches to safer fermented foods
Food safety requires action in five related areas: agriculture, food technology, nutrition, microbiology and regulations.
The quality and safety of fermented foods lie in the quality of the ‘substrate’ it is made from, such as legumes. Starting a fermentation process with a low-quality substrate creates a high risk of introducing potentially pathogenic bacteria and fungi, or toxins produced by them. Seeds and other agricultural produce used must also be of high quality and certified safe for human consumption.
- Food technology
Safe alkaline fermentation requires careful control of production conditions. Inadequate fermentation time and suboptimal temperatures may not produce the enzymes that kill pathogens and prevent toxins.
Generally, very little research has been conducted on the nutritional composition of fermented products. There is a need for more data on this. Studies should explore what influences the nutritional content of the products, such as soil characteristics, climate and the state of maturity at harvest. Data should be collected and analysed throughout the process, from the farm to processing and consumption stages. A robust measure of nutrient composition will help to formulate recommendations on daily intakes.
The safety of the particular strains of organisms used in fermentation needs more investigation. Molecular and genomic tools could be used to identify the enzyme-producing species and strains in these fermented foods.
Food regulations, policies and monitoring are needed in West African countries to overcome local challenges. Food handlers should be educated by food safety bodies on essential microbiology, hygiene and sanitation practices as they concern their products. Monitoring of compliance during production, packaging and storage in the market is essential.
The culinary traditions of West Africa offer a treasure trove of flavours and experiences. Alkaline-fermented foods, with their distinctive tastes, textures and aromas, also offer potential health benefits.
With high-quality substrates, appropriate starter cultures, the right hygiene practices, optimal pH and temperature in production, and proper storage and packaging, consumers can enjoy the region’s fermented delicacies with confidence.