UK flour maker Rank Hovis has said that it would stop using North American wheat if the US or Canada began commercial planting of genetically modified varieties of wheat due to fears the biotech wheat may contaminate non-GM grain during shipment.

Hovis Wheat director Peter Jones said that if large scale opposition to GM food remained amongst British consumers, Hovis would be forced to import high-protein grain from countries such as Germany or Australia in order to avoid contamination by GM wheat.

"If in a few years time the British public still felt the same way about GM when this wheat might be grown commercially, we wouldn't be able to use it," Jones told Reuters.

"We say that the US and Canada should beware. They export a lot of grain," Jones added.

US industry sources recently revealed that traces of GM material were managing to enter US wheat supplies. Jones said Hovis finds the odd piece of soybean or corn in its North American wheat that may have been genetically modified, but they are sifted out during processing. GM wheat, however, would be much more difficult to sift out if it found its way into a shipment of non-GM wheat.

Wheat from the US and Canada accounts for around 40% of world exports of wheat. Fearing that Canada could lose its main wheat markets, the Canadian Wheat Board last week called on Monsanto to withdraw its application to test GM wheat in Canada.

For an earlier story on contamination of non-GM wheat, click here.