(CNN) -- Lower Saxony, the state hardest hit by Germany's tainted egg scandal, has lifted a quarantine on 3,000 poultry and hog farms after tests proved negative for increased dioxin levels, officials said Monday.
The state may lift the quarantine on more farms once they get additional test results Monday, said the state's ministry for consumer protection and agriculture.
Meanwhile, Danish investigators said Monday they are looking into the possibility that contaminated animal feed from Germany may have been fed to hens in Denmark.
The feed, contamined with dioxin, was purchased by a Danish firm late last year, and brought into the country, said Kim Vandrup Sigsgaard with the Danish Veterinary and Food Administration.
"There is an ongoing investigation to see if the contaminated feed was consumed by breeder hens, which are not meant for consumption," he said.
Such hens are bred for their eggs, and not sold for their meat, he said.
Sigsgaard said his agency was warned about the feed entering Denmark by the European Union's food safety system, the Rapid Alert System for Food and Feed, on Sunday.
Last week, Germany filed criminal charges against the company at the heart of the country's tainted egg scandal.
The company, Harles and Jentzsch, apparently knew for months that fatty acid it was delivering to animal-feed makers was contaminated with dioxin, said Christian Seifert, a spokesman for the agricultural ministry in the German state of Schleswig-Holstein said.
Criminal charges have been filed against the company, Seifert said, "because they did not immediately inform" the agricultural ministry that dioxin levels surpassed the allowed amount.
Authorities allege that the company sold about 3,000 tons of contaminated fatty acids to dozens of companies making animal feed across Germany. In response, the government quarantined more than 4,700 pig and poultry farms.
Harles and Jentzsch laboratory tests from March 2010 showed they exceeded the ceiling level for dioxin, he said.
"At that point they had to stop delivering this product and immediately inform the authorities. They did not do either," Seifert said.
Government officials learned of the higher concentrations of dioxin in December, he said. CNN
