Aflatoxins
Aflatoxins are mycotoxins – toxic compounds that are naturally produced by certain types of mould (fungi). Aflatoxins are among the most poisonous mycotoxins and are produced by certain moulds (Aspergillus flavus and A. parasiticus) that grow in soil, decaying vegetation, hay, and grains. Aflatoxins pose a serious health risk to humans and livestock (WHO, 2023).
Primary reference(s)
WHO, 2023. Mycotoxins. World Health Organization (WHO). Accessed 12 May 2024.
Annotations
Additional scientific description
Aflatoxins are among the most poisonous of the mycotoxins and place communities as well as individuals at risk. Mycotoxins are toxic compounds that are naturally produced by certain types of mould (fungi). Moulds that can produce mycotoxins grow on many foodstuffs such as cereals, dried fruits, nuts and spices (see CH0601). Mould growth can occur either before harvest or after harvest, during storage, on/in the food itself often under warm, damp and humid conditions. Most mycotoxins are chemically stable and survive food processing (WHO, 2023).
Aflatoxins are difuranocoumarin derivatives with a bifuran group attached to one side of the coumarin nucleus and either a pentanone ring (B series) or a six-membered lactone ring (G series) on the other side. Major types include: Aflatoxin B1 (AFB1) and B2 (AFB2), Aflatoxin G1 (AFG1) and G2 (AFG2), and Aflatoxin M1 (AFM1) and M2 (AFM2).
Several hundred different mycotoxins have been identified, but the most commonly observed mycotoxins that present a concern to human health and livestock include aflatoxins, ochratoxin A, patulin, fumonisins, zearalenone and nivalenol/deoxynivalenol. Mycotoxins appear in the food chain as a result of mould infection of crops both before and after harvest. Exposure to mycotoxins can happen either directly by eating infected food or indirectly from animals that are fed contaminated feed, especially from milk (WHO, 2023).
Aflatoxins are produced by certain moulds (Aspergillus flavus and A. parasiticus) which grow in soil, decaying vegetation, hay, and grains and the crops that are frequently affected by Aspergillus spp. include cereals (corn, sorghum, wheat, rice), oilseeds (soybean, peanut, sunflower, cotton seeds), spices (chili peppers, black pepper, coriander, turmeric, ginger) and tree nuts (pistachio, almond, walnut, coconut, Brazil nut). Large doses of aflatoxins can lead to acute poisoning (aflatoxicosis) and can be life-threatening, usually through damage to the liver (WHO, 2023). Aflatoxins have been classified as human carcinogens by the International Agency for Research on Cancer (IARC, 2002). Aflatoxins are a particular concern for Africa (WHO, no date).
Metrics and numeric limits
The United Nations food standards body Codex Alimentarius Commission has set the maximum levels for aflatoxin in foods, including various nuts, grains, dried figs and milk (in the range 0.5-15 µg/kg; a microgram is one billionth of a kilogram) (WHO, 2023).
EU 2006: 2 µg/kg for aflatoxin B1 in nuts and dried fruits intended for direct human consumption; 4 µg/kg for total aflatoxins (B1, B2, G1, G2) in nuts and dried fruits.
Codex Alimentarius: 10 µg/kg for total aflatoxins in peanuts intended for further processing; 15 µg/kg for total aflatoxins in other nuts intended for further processing.
Key relevant UN convention / multilateral treaty
Codex Alimentarius (FAO/WHO, no date).
Drivers
Mould growth on food and the conditions that promote it are key drivers of aflatoxin poisoning events. Any event that increases consumption of decaying or contaminated food may increase the incidence of aflatoxin poisoning. Thus famines, or events that cause them (e.g. weather events) may increase this risk.
Impacts
Large doses of aflatoxins lead to acute poisoning (aflatoxicosis) that can be life-threatening, usually through damage to the liver. Outbreaks of acute liver failure (jaundice, lethargy, nausea, death), identified as aflatoxicosis, have been observed in human populations since the 1960s. Chronic exposure is responsible for a significant fraction of liver cancer cases in Africa (WHO, no date).
Aflatoxins also pose a significant economic threat (WHO, no date).
Multi-hazard context
The figure below summarises common interactions between aflatoxins and other hazards. This information should be used with caution and not be solely relied upon in Disaster Risk Management, particularly as some interactions may not have been included. Note that hazardous events occurring together or locally in space or time may not necessarily cause, amplify, or be otherwise related to each other. Specific examples of multi-hazard context can be found in the ‘Hazard drivers’ and ‘Impacts’ sections above.
Multi-hazard diagram
Risk Management
The World Health Organization (WHO) in collaboration with the Food and Agriculture Organization of the United Nations (FAO), is responsible for assessing the risk to humans of mycotoxins – through contamination in food – and for recommending adequate protection. Risk assessments of mycotoxins in food done by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) are used by governments and by the Codex Alimentarius Commission to establish maximum levels in food or provide other risk management advice to control or prevent contamination. Codex standards are the international reference for national food supplies and for trade in food, so that people everywhere can be confident that the food they buy meets the agreed standards for safety and quality, no matter where it was produced (FAO/WHO, no date).
The outcome of such health risk assessments can either be a maximum tolerable intake (exposure) level, or other guidance to indicate the level of health concern (such as the Margin of Exposure), including advice on risk management measures to prevent and control contamination, and on the analytical methods and monitoring and control activities. Tolerable daily intakes are used by governments and international risk managers, such as the Codex Alimentarius Commission, to establish maximum levels for mycotoxins in food. The maximum levels for mycotoxins in food are very low due to their severe toxicity (FAO/WHO, no date; JECFA, no date).
Monitoring
The section and the table below offer an overview of monitoring aflatoxins. This information can be used for forecasting within a national early warning system (EWS). Since EWS capacities and processes differ across countries, the most current and specific information regarding EWS should be obtained from the appropriate national or regional agency/authority responsible for disaster management.
Which institution(s) produce(s) Disaster Risk Data/Information? | World Health Organization, Food and Agriculture Organization of the United Nations, national food and agricultural authorities. |
| How is the Hazard Observed/Monitored/Forecast? | Monitoring weather conditions around crops and temperature/humidity in storage facilities will identify when the conditions are favourable for mould growth. Mould samples should be collected, cultured and analysed. Surveillance monitoring of food for aflatoxins against metrics and numeric standards will provide warning that levels are rising. |
References
European Union (EU), 2006. Commission Regulation (EC) No 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs (Text with EEA relevance) OJ L 364, 20.12.2006, p. 5–24 (ES, CS, DA, DE, ET, EL, EN, FR, IT, LV, LT, HU, NL, PL, PT, SK, SL, FI, SV) OJ L 314M, 1.12.2007, p. 558–577 (MT) Accessed 1 July 2024.
Food and Agriculture Organization (FAO) and World Health Organization (WHO), no date. Codex Alimentarius. Food and Agriculture Organization of the United Nations (FAO), World Health Organization (WHO). Accessed 12 May 2024.
International Agency for Research on Cancer (IARC), 2002. AFLATOXINS (Group 1) - Summaries & Evaluations. International Agency for Research on Cancer (IARC). Accessed 12 May 2024.
Joint FAO/WHO Expert Committee on Food Additives (JECFA), no date. Evaluations of the Joint FAO/WHO Expert Committee on Food Additives: Aflatoxins, WHO | JECFA. Accessed 12 May 2024.
United Nations Economic Commission for Europe (UNECE), 2023. Globally Harmonised System (GHS) of Classification and Labelling of Chemicals (2023). United Nations Economic Commission for Europe (UNECE). Accessed 11 May 2024.
World Health Organization (WHO), 2023. Mycotoxins. World Health Organization (WHO). Accessed 12 May 2024
World Health Organization (WHO), no date. The Need for Integrated Approaches to Address Food Safety Risk: The Case of Mycotoxins in Africa. Accessed 10 April 2025.