More than 4,700 German farms have been closed after large amounts of animal feed were found to be contaminated with dioxin, a poisonous chemical.

德国超过4700座农场因发现大量动物饲料被二恶英污染而关闭。

Officials insist the levels of dioxin（二恶英） do not pose a risk to humans, and that the closures are only a precaution.

Most of the affected¹ farms are in Lower Saxony region, north-west Germany.

Meanwhile, the EU has warned that eggs from farms affected by dioxin have entered the UK in processed products destined² for human food.

Last week, more than 1,000 farms were banned from selling eggs after dioxin was found in eggs and poultry³（家禽） .

Dioxin is linked to the development of cancer in humans.

It is believed that the poison reached the animal feed after being distributed by a company in northern Germany which supplies additives⁴ for animal feed.

The dioxin was discovered in late December, but the extent of the problem was only revealed earlier this week when German officials said 3,000 tonnes of feed had been affected.

Germany's agriculture ministry⁵ said on Thursday that most of the closed farms were ones raising pigs.

The ministry said the farms would not be allowed to make any deliveries until they had been checked and found to be clear of contamination（污染） .

And European Commission health spokesman Frederic Vincent told a news conference how the problem had now reached Britain.

"Those eggs were then processed and then exported to the United Kingdom... as a 14-tonne consignment⁶（委托，运送） of pasteurised product for consumption," he said.

"Whether it went into mayonnaise（蛋黄酱） , pastries⁷（点心，甜点） , I don't know. So we will probably take a look at this with the UK authorities and see what was done with these eggs."