Protect Stored Grain from OTA Contamination

Simple steps to prevent mycotoxin buildup in stored cereals 

Preventing ochratoxin A (OTA) contamination in stored cereal grains is essential to protect both farm investments and market access. OTA is a naturally occurring mycotoxin produced by Penicillium verrucosum, a soil fungus that thrives under high moisture conditions.  

Unlike field-based toxins such as deoxynivalenol (DON), OTA forms exclusively in storage, making post-harvest management critical. 

The main causes of OTA contamination include contaminated soil, unclean grain handling equipment, leftover grain from the previous year, and residue buildup inside bins. Even small pockets of wet grain can allow OTA to form, especially when condensation occurs or water leaks into the bin. All storage facilities, regardless of condition, can be at risk. 

As international grain buyers tighten regulations on OTA limits, farmers must adopt strict on-farm practices to prevent contamination.  

To minimize risks, Keep it Clean recommends several best management practices: 

• Cool grain as quickly as possible after harvest and maintain temperatures well below 10°C, ideally below freezing, to prevent fungal growth. 

• Clean bins and handling equipment thoroughly between grain lots to eliminate dust, debris, and leftover residues. 

• Ensure crops are harvested or dried to safe moisture levels before storage. Avoid blending tough or damp grain with dry grain. 

• Monitor bin temperatures regularly; if any increase is detected, move about one-third of the grain to restore uniform cooling. 

• In spring, recondition grain when ambient air is warm enough for drying. 

By keeping bins clean, grain cool, and moisture under control, farmers can significantly reduce the risk of OTA contamination. These careful storage practices protect grain quality, maintain export readiness, and help ensure stable market access for all producers. 

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