Aflatoxin Testing for Groundnuts and Maize in Africa (2026)

Few quality problems can cost a groundnut or maize business as much as aflatoxin. A buyer who rejects a consignment on a test result is rejecting your money, your time and your name. This guide to aflatoxin testing for groundnuts and maize in Africa explains what aflatoxins are, where the risk comes from, which steps reduce it on the farm, in the store and in the factory, and why buyers and regulators ask for test results. We rely on WHO, the African Union's aflatoxin partnership and NAFDAC documents. We do not give medical advice, and we do not quote legal limits except where a source states them. Check the current limits and test methods with your regulator and buyer (information as of October 2026).

What aflatoxins are and which crops are at risk

The WHO fact sheet on mycotoxins (dated 2 October 2023) describes aflatoxins as toxins produced by moulds that can grow on foods. It lists cereals such as maize, sorghum, wheat and rice, and oilseeds such as groundnuts among the commonly affected foods, along with spices and tree nuts. WHO says mould often grows in warm, damp and humid conditions, can develop before harvest or during storage, and that damaged grain is more vulnerable. It also says mould usually does not grow in properly dried and stored foods. That one point explains most of the practical advice that follows: keep the crop dry, undamaged and clean.

WHO adds that aflatoxins are a serious health concern, that large doses can cause acute poisoning, and that aflatoxin M1 can pass into milk from animals fed contaminated feed. That is why poultry feed makers and dairy suppliers also pay attention to maize quality. Read the WHO mycotoxins fact sheet.

Why aflatoxin testing matters for trade in Africa

A WHO document on mycotoxins in Africa says maize and groundnuts, along with sorghum and millet, are often heavily contaminated staples. Its authors argue that aflatoxin contamination has blocked Africa's groundnut exports to Europe and that a compliant supply chain could help the continent regain market share. They also say no single measure is enough and recommend interventions across the whole value chain, from resistant crops, good agricultural practices, improved storage and biocontrol to hand-sorting, optical sorting and dry milling. You can read it as The Need for Integrated Approaches to Address Food Safety Risk: The Case of Mycotoxins in Africa.

The African Union Commission is involved in the Partnership for Aflatoxin Control in Africa (PACA). The PACA website lists five strategic areas: research and technology, policies and standards, capacity, public awareness, and growing commerce and trade while protecting human health. If you sell groundnuts, maize or products made from them in Kano, Kaduna or Kampala, following good practice on drying, storage and testing can help you answer careful buyers.

Limits and what they mean for you

WHO says Codex sets maximum levels for aflatoxins in foods including nuts, grains, dried figs and milk, and that the maximum levels it lists fall in a range from 0.5 to 15 micrograms per kilogram. The level that applies to your product depends on the food, the country and the buyer. Do not assume that one number fits everything. Ask your regulator for the limit that applies to your product and ask your buyer what they require, then test against that figure.

Where to act: farm, store and factory

Because mould grows when conditions allow, control is a chain of small actions:

• At harvest. WHO advises avoiding damage to grain before and during drying.
• Drying. Dry quickly and thoroughly. WHO says mould usually does not grow in properly dried and stored foods.
• Sorting. The WHO paper lists hand-sorting and optical sorting among methods used to cut contamination. Discard visibly mouldy, discoloured or shrivelled kernels.
• Storage. WHO advises keeping food dry, free of insects and not too warm. See our guide to cold chain and storage for storage points.
• Processing. Keep records for each batch so a problem can be traced to a supplier and a date.
• Biocontrol and varieties. The WHO paper lists biocontrol and resistant crops as options. Your agricultural extension service or research institute can advise on what is available in your area.

How testing usually works for a food business

The exact method is something to agree with your lab and your buyer, not something to guess. In practice, there are three common situations:

1. Check at intake. If you buy groundnuts or maize from farmers or traders, decide in advance how incoming lots will be sampled and tested before you accept them, so a bad lot does not contaminate a good one.
2. Test finished lots. Many buyers ask for a certificate of analysis for a batch. Ask the buyer which tests, which method and which laboratories they accept.
3. Test for registration. NAFDAC's guidelines for registration of food products made in Nigeria list a Certificate of Analysis (section 3.1.7) among the documents for registration. Read them on the NAFDAC website, and see our guide to NAFDAC registration for food products.

Sampling matters as much as the test: a small sample must represent a large lot, and the method for taking it should follow what your laboratory or buyer specifies. Keep the report with the batch records.

Products where this matters most

Groundnut oil, peanut butter, roasted nuts, maize flour, grits and poultry feed all start with crops at risk. Our guides on groundnut oil and peanut processing in Nigeria and maize processing for flour and poultry feed cover the products. Selling in bulk across borders, for example in Uganda, adds the buyer's own specifications on top, so ask for them early.

Frequently asked questions

What is aflatoxin? According to WHO, aflatoxins are toxins produced by moulds that can grow on crops such as maize and groundnuts, often in warm, damp and humid conditions.

Can I see aflatoxin on the grain? Not reliably. WHO suggests inspecting and discarding visibly mouldy, discoloured or shrivelled grain, but a test is the way to know what is in a lot.

What is the legal limit for aflatoxin in my product? It depends on the food and the country. WHO says Codex maximum levels for various foods fall within a range from 0.5 to 15 micrograms per kilogram. Ask your regulator and buyer for the level that applies.

Does drying remove the risk? Good drying and storage help prevent mould growth, but prevention is not a test result. Sorting and testing show what is actually in a lot.

Which laboratory should I use? Ask your buyer and your regulator which laboratories they accept, and ask the lab about its methods and reporting.

Getting started

Strong aflatoxin control and testing for groundnuts and maize in Africa builds the trust that bulk buyers look for. When your records and test reports are ready, apply as a supplier for free at /apply-manufacturer and choose the category that fits your products. Admin review is stated on the form as about 24 to 48 hours, and we cannot promise that any application will be accepted.