According to the Lower Saxony ministry of agriculture and food, the eggs that were found to have more than the legal limits of dioxins and dl-PCBs were found on a farm in the Emsland district.

The legal limit is 5 pg/g (picograms per gram of egg fat), and the ministry said the test results showed the eggs contained 19.5 pg/g.

The producer is a free range operation with 12,000 birds and the authorities closed the farm down on 18 June.

Following the discovery of the contamination the sale of further eggs was stopped and those that had already been sent to market were recalled, although the ministry said it is possible that some of the eggs have already been eaten.

The ministry said that eggs with the code 0-DE-0,356,091th and a sell by date of 14 June and later should be destroyed or returned.

However, the Lower Saxony authorities said there were was no risk from the eggs.

The authorities have now launched an inquiry into the incident.

Dioxin was found in eggs on farms in Lower Saxony and in North Rhine Westphalia in April and May.

In January, there was a health alert of potential contamination of eggs, poultry meat and pork after feed had been found to be contaminated.