Mycotoxins are toxic secondary metabolites produced by moulds (fungi) that contaminate food and animal feed. They are among the most widespread food contaminants globally, affecting an estimated 25% of the world's food supply. The most toxicologically significant mycotoxins include aflatoxins (particularly aflatoxin B1 — the most potent naturally occurring carcinogen known), ochratoxin A, fumonisins, deoxynivalenol (DON), zearalenone, and patulin. Climate change is increasing mycotoxin contamination in European crops as temperatures rise.
Where it's found
Aflatoxins: groundnuts (peanuts), tree nuts, maize, dried figs, and spices — particularly in warm, humid regions or poorly stored crops. Ochratoxin A: cereals (wheat, barley, oats, rye), dried vine fruits (raisins, currants, sultanas), coffee, wine, beer, grape juice, dried figs, and spices. Fumonisins: maize and maize-derived products (polenta, tortillas, corn-based breakfast cereals). Deoxynivalenol (DON/vomitoxin): wheat, barley, oats, rye, and derived products — bread, pasta, breakfast cereals. Zearalenone: maize and wheat. Patulin: damaged apples and apple products including juice — patulin is produced by Penicillium expansum in mouldy apples.
Routes of exposure
Dietary ingestion is the sole route of significance. Mycotoxins are chemically stable, heat-resistant, and persist through processing — cooking does not destroy them. Aflatoxins pass into meat, eggs, and milk of animals fed contaminated feed (particularly aflatoxin M1 in milk is a specific concern for infants). Ochratoxin A accumulates in pigs and poultry fed contaminated grain. People in lower-income countries with less food safety infrastructure, who rely heavily on maize and groundnuts as staples, carry the greatest mycotoxin burden globally.
Health concerns
Aflatoxin B1 is the most potent naturally occurring carcinogen known — it is an IARC Group 1 carcinogen causing hepatocellular carcinoma (liver cancer). In regions with high aflatoxin exposure and concurrent hepatitis B infection, the risk of liver cancer is synergistically increased up to 30-fold. Acute aflatoxicosis at very high doses causes liver failure and death. Ochratoxin A is an IARC Group 2B possible carcinogen, nephrotoxin, immunosuppressant, and possible teratogen. Fumonisins are associated with oesophageal cancer and neural tube defects. DON causes nausea, vomiting, immunosuppression, and growth impairment in animals — effects at lower concentrations in humans include reduced immune function and gut barrier disruption. Zearalenone is an oestrogen mimic causing reproductive disruption.
Evidence
Aflatoxin B1 Group 1 carcinogenicity is unequivocally established. Ochratoxin A Group 2B classification has solid animal evidence. The hepatitis B–aflatoxin synergy is one of the most striking gene–environment interaction examples in cancer epidemiology. Fumonisins and neural tube defect association from South African studies is well supported. European dietary exposure assessments by EFSA consistently find some population groups (high cereal consumers, young children) approaching or exceeding tolerable daily intakes for ochratoxin A and DON.
Who's most at risk
Infants and young children are particularly sensitive to the growth-suppressing and immunosuppressive effects of DON and to aflatoxin M1 in formula and dairy. Pregnant women are of concern for fumonisin exposure and neural tube defect risk, and for aflatoxin's fetotoxic effects. Populations in sub-Saharan Africa, South and South-East Asia with high groundnut and maize dependence carry the greatest aflatoxin burden. Hepatitis B carriers face dramatically increased liver cancer risk from aflatoxin co-exposure. Immunocompromised individuals are more susceptible to mycotoxin-induced immune suppression.
Regulatory status
RegulationEU Regulation 1881/2006 sets maximum limits for aflatoxins, ochratoxin A, fumonisins, DON, zearalenone, and patulin in food and feed — with stricter limits for infant and baby foods. UK retained these regulations post-Brexit with minor modifications. The EU and UK regularly test imported produce at borders — groundnuts from certain origins are subject to enhanced checks. EFSA conducts regular dietary exposure assessments and recommends downward revision of limits as evidence develops.
How to reduce your exposure
Buy from reputable sources where food safety standards are maintained. For nuts and dried fruits, purchase from major retailers with supply chain controls rather than loose from unregulated sources. Store nuts, grains, and dried fruits in cool, dry, airtight conditions — moisture and warmth favour mould growth. For apple products, do not use damaged or mouldy apples in home juice making — patulin contamination of visually mouldy fruit is high and does not reduce on juicing. Do not feed mouldy bread or grain to chickens or pigs if planning to consume their eggs or meat. Varied diet across grain types reduces dependence on any one potentially contaminated crop. For infants, ensure formula and cereal products are within date and properly stored.
The nutrition connection
Mycotoxins provide a particularly interesting entry point for Nutriofia's nutritional perspective because certain nutrients directly modulate mycotoxin toxicity. Selenium, vitamin E, and beta-carotene reduce the oxidative damage caused by aflatoxin and ochratoxin. Adequate riboflavin (B2) and niacin (B3) support the liver detoxification pathways that process mycotoxins. Chlorophyllin (from green vegetables) binds aflatoxin in the gut and reduces absorption — a finding directly supported by human intervention studies. A nutrient-rich, varied diet provides multiple layers of biochemical protection against the mycotoxins that inevitably enter the food chain at low levels.