German farmers and food producers came under increasing pressure on Wednesday as China became the second country after South Korea to ban the import of German chicken and pork products.
The announcement by China's general administration of quality supervision, inspection and quarantine came only hours after German state authorities said that traces of dioxin had been found in pigs.
The poisonous chemical had already been found in eggs and chicken, leading to a ban of meat and poultry shipments from around 5,000 farms in the past week.
While it was unclear whether contaminated pork had entered the food chain, tainted eggs reached supermarket shelves in Germany and were exported to several European Union countries.
The agriculture ministry in Lower Saxony, where the contamination was first discovered at Christmas, said 4,100 farms in the northern state were working normally again, while 330 were still waiting for test results.
On Tuesday the ministry ordered the slaughter of 140 pigs on a farm in the state after tests showed the animals contained more dioxin than the legal limit. Some pork may have reached supermarket shelves, officials said.
According to the federal government, 3,000 tonnes of polluted vegetable oil may have been used as an additive to make 150,000 tonnes of animal feed, which was then served to pigs and chickens in November and December.
According to German authorities, the poisonous chemical entered the food chain when contaminated fatty residues from a bio-diesel power plant were mixed with other vegetable fats, a vital ingredient for animal feeds.
Federal farm minister Ilse Aigner repeated her call for the separation of industrial and agricultural uses of vegetable fats, promising an "action plan' for Friday.
Mixed federal and state-level responsibility for farm policy and monitoring standards appears to have slowed Germany's policy response.
A spokesman for the EU's health commissioner said German animal-feed makers failed to propose new measures at a meeting in Brussels. "They did not come back because they said there were other actors involved,' he said.
The industry's reticence means the European Commission may draw up its own proposals, although its main concern ? the better separation between fatty acids designated for industry and those intended for animal feed ? is shared by Berlin.