Zearalenone (ZON) is a mycotoxin produced by the fungi Fusarium graminearum, which is responsible for Fusarium head blight in wheat. The presence of elevated levels of ZON in grain is particularly associated with rainfall at harvest. 

Grain delivered to UK mills is tested (using rapid test kits) for ZON as part of millers ‘due diligence’ procedures.  If levels in the grain exceed the legal or contractual maximum, the grain is rejected. Additionally, a monitoring project is run by the AHDB which examines levels in grain as they are delivered throughout the season.  The presence of ZON in UK crops is usually low and this is reflected in the results from the mill testing and independent monitoring of grain.

Legal limits are established for the presence of ZON in grain, as follows:

UK Legal ZON Limits in Grain Intended for Human Consumption

  ZON (ppb)
Unprocessed common wheat and barley 100
Unprocessed durum wheat and oats 100
Flour 75
Finished products 50
Infant food 20