Ochratoxin A (OTA) is a mycotoxin produced by the fungi Aspergillus ochraceus and Penicillium verrucosum. The presence of OTA is normally associated with poor storage conditions rather than developing in the field, but the factors that affect this are not yet clear. Nevertheless, prevention is achieved by drying and cooling grain promptly after harvest and ensuring that it remains in this condition throughout the storage period. Advice to farmers is available in the HGCA’s grain storage guide.

EU legal OTA Limits

If consumed at high levels, OTA can have a distructive effect on the kidneys. The European Food Safety Authority (EFSA) therefore decided, in 2006, on a tolerable weekly intake (TWI) for OTA of 120 ng/kg bodyweight.

The EU has also set legal limits for OTA in various foodstuffs as follows:

  (OTA (µg/kg)
Unprocessed cereals 5.0
Products derived from unprocessed cereals 3.0
Processed cereals based foods and baby foods 0.5
Foods for special medical purposes intended specifically for infants 0.5

nabim has run a monitoring programme for OTA in wheat used by millers since the 1990s. Any non-compliance with legal limits is extremely rare.