GRAIN from experimental field trials of GM rice in the United States has been contaminating European food supplies, including baby food, for months.

All shipments of rice from the United States was banned by the European Union last week after the US Government admitted that the banned long-grain rice, developed by Bayer CropScience, was widespread in exports to Europe.

US rice will only be allowed into Europe after tests to prove it is GM-free.

The contamination was discovered in January but Bayer only informed the US Government on July 31, and the Bush administration waited another 18 days before making the information public.

Britain has imported large quantities of long-grain rice from the US since the problem was first discovered and no one knows how much of this was contaminated, but the Food Standards Agency is planning tests on unsold rice.

A spokeswoman for FSA Wales said, "The agency will act to implement the necessary controls required of EC member states.

"These involve requesting local authority enforcement authorities to step up border-control checks on US long-grain rice consignments for the required GMO-free certification, as well as carrying out sample testing on products already on the market."

It appears that American long-grain rice has been contaminated with the banned GM organism for years. Bayer decided not to market the grain after field tests on US farms between 1998 and 2001. The reasons for the decision are not known.

In Arkansas, one of several areas of the US involved in the crisis, the state government believes that the problem originated when pollen spread from GM rice to conventional crops.

Richard Bell, the Arkansas agriculture secretary, admitted that the contamination is "widespread" and predicted that it would show up again in this year's crop.

The campaign group GM Free Cymru yesterday called on supermarkets to remove all products containing long-grain rice from the southern United States off their shelves until they have proof that they are free from contamination.

Spokesman Dr Brian John said the contamination was much more serious than the Bt10 incident which made the headlines last year.

"American long-grain rice is a primary food consumed in a virtually unprocessed form by millions of consumers across the EU," said Dr John.

"It is also widely used in baby food as a cereal, recommended for use early in the weaning process."

Dr John said the contamination was "hushed up" by Bayer and by the American government and long-grain rice from the southern Unites States continued to be shipped to the EU at a rate of more than 20,000 tonnes a month.

"That adds up to 140,000 tonnes and it is absolutely certain that rice containing LL601 is already in the food supply chain," he said.

"In our book that amounts to criminal negligence by Bayer and the US administration."

Wales Euro-MP Jill Evans described the contamination as "very serious" and said it undermined any confidence the EU had left in the US regulatory system.

"The fact that Bayer knew about it months before disclosing this means we can't rely on the information and tests that they give us," she said.

Ms Evans said current EU restrictions were "inadequate".

"There must be an immediate ban on all long-grain rice imports from the USA and shops should be advised to withdraw stock that contains recent unprocessed US long-grain rice," she said.

"But a longer-term solution is needed. We can't keep on reacting to these contamination 'accidents'.

"I am writing to the European Commission urging them to identify countries and products that have high risk of contaminating our food with GMOs and to implement strict screening and testing on these products before they can enter our food market."