Germany has escaped a European Union ban on organic food exports, after discovering that tainted grain had been fed to organic chickens.

A banned carcinogenic herbicide, nitrofen, was found in grain, of which 550 tons was distributed to farmers.

Following an emergency meeting on Tuesday the European Commission ruled that Germany had implemented adequate safeguards after it discovered the contamination, so further action was not needed for the moment.

The German government has promoted organic farming

A grain store used to house pesticides and weed killer during the days of communist East Germany appears to have been the sole source of the herbicide, the German government has said.

Hundreds of thousands of organic chickens have been slain and organic eggs and poultry taken off the shelves.

Production of organic chickens, eggs and other poultry has been halted in 93 German farms.

Strict inspections

Belgium has already passed emergency legislation blocking entry of German foodstuffs unless they carry a certificate showing they are free of nitrofen.

In France, there are reports that bakeries need to be on alert for tainted wheat after an organic miller said he had imported and sold on more than six tonnes of potentially contaminated grain from Germany.

Gerald Herrmann, head of Naturland - a German association of organic producers and consumers - told the BBC's World Business Report that these scares were difficult to avoid.

"What we can do is install a system which inspects on a very strict level," he said.

"But we will find from time to time, in food, residues coming from the conventional system.

"Organic agriculture... is being surrounded by conventional farms, by the conventional system, which is still using pesticides."

The number of organic farms was rising in Germany before the scare, said Thomas Dosch, head of the ecological farming association, Bioland.

"Now conventional farmers are very careful when thinking of converting to organic farming and it will take time to convince them again," Mr Dosch said.