HAMBURG (Reuters) - The poisonous chemical dioxin has been found at higher-than-permitted levels in eggs from a German farm, following similar discoveries at seven other farms since April, authorities said on Monday.

The poultry farm is near Loehnberg in the central state of Hesse, the federal food warning service said. The dioxin was discovered by the farm's own safety checks, and the eggs are being recalled, it said.

The service said there was no acute danger to public health, because dioxin is dangerous only if consumed over long periods. Small doses are not harmful.

The previous dioxin discoveries were in eggs at farms in Lower Saxony and the neighboring state of North Rhine Westphalia. The cause of some outbreaks in Lower Saxony was contaminated earth.

In January 2011, German officials said animal feed tainted with dioxin had been fed to hens and pigs, contaminating eggs, poultry meat and pork at affected farms, triggering a European Union-wide health alert.

Germany then introduced a series of measures including restrictions on animal feed ingredients and increased inspections of farms and feed.