BERLIN — Sales of poultry, pork and eggs from more than 4,700 farms in Germany were stopped by that country on July 7 after animal feed was discovered to be contaminated with cancer-causing dioxin, according to The Associated Press. Meanwhile, authorities are rushing to uncover how far the tainted food had spread.

On Jan. 7, South Korea and Slovakia banned the sale of some animal products imported from Germany, while authorities in Britain and the Netherlands were investigating whether food containing German eggs — like mayonnaise or liquid egg products — was safe to eat.

Prosecutors in the northern state of Schleswig-Holstein have launched an investigation into the German firm Harles & Jentzsch GmbH, suspecting the company knew but failed to tell authorities that fat it had produced for use in feed pellets was tainted with dioxin. AP charged.

Test results released Jan. 7 on the fat showed some of it contained more than 77 times the approved amount of dioxin, the state's agriculture minister said. Out of 30 samples tested so far, 18 contained more dioxin than legally allowed.

Dioxins are contaminants that typically result from industrial combustion and other chemical processes. Exposure to dioxins at high levels is linked to an increased incidence of cancer.

Authorities believe 150,000 tons of feed pellets for poultry and swine may contain the contaminated industrial fat produced by Harles & Jentzsch. They are trying to determine how widespread the contamination may be and how long the tainted feed has been in circulation.

The scandal broke after regular random testing revealed excessive dioxin levels in eggs from chickens in the west of the country earlier this week. More than 8,000 chickens were ordered slaughtered and tainted food fears spread to Germany's famous pork industry.

Germany's Agriculture Ministry said Friday it had no immediate reports of health problems connected to the contaminated food, but it was stopping the sale of products from certain farms as a precaution until more tests could be carried out. About 1% of the country's farms have been affected so far.