Fusarium mycotoxins and limits in UK grain

Infection of cereals by fusarium pathogen species can cause various symptoms, with the production of mycotoxins in grain a major concern. Learn about the mycotoxin limits in place to protect consumer safety.

Several of the fungal pathogen species that cause fusarium head blight (FHB) in UK cereals also produce mycotoxins of varying toxicity to humans and animals.

Fusarium mycotoxins include:

• Deoxynivalenol (DON)
• Nivalenol (NIV)
• Zearalenone (ZON)
• T-2 and HT-2

DON, NIV and ZON are mainly produced by Fusarium culmorum and F. graminearum.

T-2 and HT-2 are mainly produced by F. langsethiae (which is the main species that infects oats).

Other mycotoxin-producing species include F. poae and F. avenaceum.

Fusarium species are not the only group of fungi that produce mycotoxins. For example, they are also produced by Claviceps purpurea (ergot alkaloids) in the field and by Penicillium verrucosum (ochratoxin A) in stored grain.

Mycotoxin risk varies between regions and years depending on climate and the intensity of host crops in the region.

Notes

Mycotoxins formed before harvest are stable and likely to remain during storage (but not increase). 

Microdochium nivale and M. majus do not produce mycotoxins.

There are rules and strict limits for mycotoxins in certain foods to protect consumer safety.

Maximum levels (MLs) are established in:

• Assimilated Regulation (EU) 1881/2006 for England and Wales
• Regulation (EU) 1881/2006 for Northern Ireland

The grain owner (farmer, merchant or processor) is legally obliged to ensure grain is safe for human consumption.

This means that all sellers must be able to demonstrate due diligence in determining the levels of mycotoxins that are present.

Generally, mycotoxin levels are much lower in the UK than in mainland Europe and rarely exceed GB and EU limits.

Since Brexit, there has been some divergence in the approaches between Great Britain (GB) and Northern Ireland (NI).

Businesses moving goods between GB to NI should read the Windsor Framework.

Definitions

• Maximum levels (MLs): Legal limits for specific mycotoxins in cereals and cereal products, which are applied at the point of sale (as defined by regulations)
• Indicative levels: Levels where exceedances should be investigated to identify mitigating actions to reduce levels to As Low As Reasonably Achievable (ALARA)
• Guideline limits: Voluntary limits for feed and feedstuffs to guide decisions and management

There are legal limits (L) for DON and ZON in wheat, barley and oats intended for human consumption and guidance limits (G) for grain for animal feedstuffs (see Table 1).

The guidance values are published by the EU (but not laid down in GB legislation).

Table 1. GB limits for DON and ZON mycotoxins (ppb) in grain.

*On 1 July 2024, new reduced maximum levels for DON came into force (only apply to NI and EU countries).

Processors may specify a lower limit at intake than the legal limit for unprocessed cereals to ensure finished products conform to legal limits.

On 1 July 2024, the European Commission published maximum levels for the combined concentration of T-2 and HT-2 in food, which apply to EU Member States and NI (REGULATION (EU) 2024/1038).

In GB, there are currently no legal or indicative limits for T-2 and HT-2. However, GB is voluntarily following the indicative levels for T-2 and HT-2 that were in place prior to 1 July 2024 (these did not form part of retained legislation at the point of EU exit).

Table 2. EU maximum levels for the combined concentration of HT-2 and T-2 (ppb) in unprocessed cereals (only apply to NI and EU countries).