How to minimise erucic acid risks in oilseed rape

Higher than expected levels of erucic acid have been found in seed grown from double-low oilseed rape (OSR) varieties. These guidelines* highlight the key points where management of erucic acid levels can make a difference.

Erucic acid is a naturally occurring fatty acid found in both OSR and related species (including several weed species associated with arable systems).

Most UK-grown OSR varieties are ‘double-low’ – also called ‘double-zero’ and ‘00’. Such varieties have a low erucic acid content, making seeds suitable for both human and animal consumption.

For rapeseed oil use in food products, the law states that erucic acid levels must not exceed 5%. The current maximum level in most contracts is set to 2%. The European Commission plans to change the legal food standard to 2%.

The detection of higher than expected levels of erucic acid in seed grown from some double-low varieties recently, with some deliveries exceeding the 2% level, is a concern. With standards becoming tighter, it is essential to minimise erucic acid in double-low OSR to meet standards and avoid penalties or rejections.

There are several risk points during the production cycle where management can make a difference to erucic acid levels – from seed source to harvested crop.

It is also important to keep records, sample grain and be aware of the testing involved with the investigation of any exceedance of legal and/or contractual limits.

The risk of erucic acid contamination from certified seed is likely to be low. However, farm-saved seed sources are associated with elevated risk. Find out the steps you can take to manage seed-source risks.

Shed seeds of oilseed rape can remain viable in fields for many years. Such seeds are associated with variable levels of erucic acid, which can contaminate the main crop. Because a single volunteer OSR plant can produce around 2,000 to 10,000 seeds, it is clear to see why their management is essential.

Although OSR volunteers are the principal cause of elevated levels of erucic acid, the high erucic acid status of some weed species means both require management across the rotation. Find out about the key erucic-acid-producing weeds and access our weed management resources.

There are several steps you can take during the harvest period to manage erucic acid risks. Firstly, to harvest the crop at the optimum stage of maturity (to avoid shed seeds). Secondly, to segregate crops at higher risk. Thirdly, to keep representative samples. Finally, to be aware of the common pitfalls associated with grain contracts.

The following organisations contributed to the development of this guidance.