Mycotoxins: your questions answered

Last updated:
18 February 2010
What are mycotoxins and why are they of concern? Find out the answers to these and other general questions.
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1. What are mycotoxins?

Mycotoxins are a group of naturally occurring chemicals produced by certain fungi that can grow on various foodstuffs such as cereals, nuts, dried fruits and spices. Mould growth can occur either pre-harvest or post-harvest during storage or on the food itself often under warm, damp and humid conditions. Most mycotoxins are chemically stable and survive food processing.

The most commonly observed mycotoxins that may present a concern to human health include aflatoxins, ochratoxin A, patulin, fumonisins, zearalenone and the trichothecenes including nivalenol and deoxynivalenol.

2. Why are they of concern?

Mycotoxins may cause a variety of different adverse health effects in humans. Aflatoxins, including aflatoxin B1, are the most harmful and have been shown to be genotoxic i.e. can damage genetic material such as DNA and potentially cause cancer in animal species. There is also evidence that they can cause liver cancer in humans. Other mycotoxins may cause a range of other health effects including kidney damage, gastrointestinal disturbances, reproductive disorders or suppression of the immune system.

3. What foods do mycotoxins occur in?

Mycotoxins can occur in a wide range of different foodstuffs. These include cereal-based products such as bread, breakfast cereals, pasta, pastries, biscuits and snacks; groundnuts (peanuts), tree nuts, oilseeds, dried fruits, spices, coffee, wine, apple juice and milk.

4. How are consumers protected from mycotoxins?

For most mycotoxins where there are maximum levels set in EU legislation, a Tolerable Daily Intake (TDI) has been established, which is an amount that is considered safe to consume daily over a lifetime without appreciable health risk. This helps to set maximum levels for mycotoxins in food and ensure that consumers are not exposed to levels of mycotoxins that would otherwise be of concern. Within the EU, this work is carried out by the European Food Safety Authority (EFSA) and previously by the EC’s Scientific Committee on Food (SCF).

5. What is the role of the FSA regarding mycotoxins?

The Food Standards Agency aims to ensure that the mycotoxins present in food do not compromise food safety. You can find more information about the Agency’s role on chemical contaminants at the link below.

6. What maximum levels are in place for mycotoxins and what food products are covered by these?

Maximum levels are set for various mycotoxins including aflatoxins, ochratoxin A, patulin and the Fusarium toxins, which currently comprises deoxynivalenol, zearalenone and fumonisins. The maximum levels are set for those foods that are susceptible to mycotoxin contamination and that contribute a significant amount to consumers’ total dietary intake. They are also set based on what is considered reasonably achievable by following good agricultural and manufacturing practices.

The principal piece of EU legislation governing mycotoxins is Commission Regulation (EC) No. 1881/2006, as amended. This Regulation sets out specific rules in relation to mycotoxins and includes specific maximum levels for certain mycotoxins in individual foodstuffs, which are laid down in section 2 to the annexe of the Regulation.

7. Why aren't the maximum levels set at zero?

Mycotoxins are naturally occurring toxins, so their presence in foods cannot be avoided completely. In the case of mycotoxins that are considered to be genotoxic carcinogens, or in cases where current exposure of the population is close to or exceeds the TDI, a limit is set that is considered as low as reasonably achievable. Such approaches ensure that food businesses apply measures including good agricultural practice and good manufacturing practice to prevent and reduce mycotoxin contamination as far as possible in order to protect public health. Very low limits have also been set for the health protection of infants and young children in foods that are specifically intended for this more vulnerable group.

8. Why are there higher maximum levels for some commodities?

The higher maximum levels for unprocessed commodities recognise that sorting or other physical treatments make it possible to reduce the content of some mycotoxins (e.g. aflatoxins) in consignments of nuts, oilseeds, dried fruit, maize and rice. The maximum levels are set taking into account the effectiveness of the various post-harvest treatments. To enable effective enforcement and to ensure that commodities with these higher levels are not placed on the market for direct human consumption, food businesses must label the consignments appropriately.

9. Why are some commodities exempt from the maximum levels?

As aflatoxins are nearly completely removed by the refinement process of vegetable oils, it is appropriate to exclude groundnuts and other oilseeds intended for crushing for refined vegetable oil, crude vegetable oil destined for refining as well as refined vegetable oil itself from the maximum levels. Unprocessed maize intended for wet milling is also excluded from the maximum limit since scientific data have shown that Fusarium toxins are removed during this process and do not end up in the starch fraction.

10. What testing is done for mycotoxins to ensure foods are safe?

A range of tests is conducted on products for which there are maximum levels or which are known to be susceptible to mycotoxins, to ensure that they do not present a concern to consumer safety.

Regular monitoring is carried out by port health authorities on imports of commodities and local authorities also monitor retail products. Additionally, there are special import conditions for some foods that present an increased risk of mycotoxin contamination. These controls ensure further protection to consumers from mycotoxins in imported foods that are placed on the market within the EU. Monitoring is also conducted by industry and enforcement authorities as part of their quality assurance procedures and to ensure that foods are safe for consumption.

Periodic surveillance is also undertaken by the Food Standards Agency to help monitor mycotoxin presence in foods. This surveillance is targeted towards where the Agency considers there could be a potential food safety risk based upon current evidence. You can find details of current and past surveys at the 'Food surveys' link below. The Agency also works with local authorities across the UK to improve the controls over imported foods that may be affected by mycotoxins (see link below).

11. Do mouldy foods contain mycotoxins?

Mouldy foods can potentially be contaminated with mycotoxins, produced by certain fungi, and can be harmful when consumed. It is therefore advisable to discard food if it is showing signs that it is mouldy. More information on mouldy foods can be found in the Natural Toxins Factsheet (see link below).