German officials said Friday that a carcinogenic substance had been discovered in animal feed delivered to more than 3,500 farms but stressed that any risk to humans was unlikely.
The contamination originated from a delivery of maize from Serbia which went into making animal feed for 3,560 farms in western Lower Saxony state, the region's ministry for food, agriculture and consumer protection said.
The substance, Aflatoxin B1, is a substance with "a strongly carcinogenic effect" that comes from mould, it said.
However, preliminary investigations showed there was a negligible risk to humans either through milk from cows fed with the contaminated feed or from eating meat.
"A danger for consumers through Aflatoxin-affected milk can be considered unlikely given the processes undertaken by dairies," the ministry said in a statement.
Unprocessed milk from several farms is mixed together and then processed by dairies, which conduct monthly checks for high levels of Aflatoxin, the ministry explained.
Thus far, no excessive levels had been discovered.
The original delivery from Serbia contained 45,000 tonnes of maize.
Ten thousand tonnes were stopped in the port and 25,000 tonnes in a granary.
The remaining 10,000 tonnes were delivered to 13 animal feed producers in Lower Saxony, processed, and then sent on to regions throughout Germany and a small amount to the Netherlands.
Regional authorities have informed the federal ministry.
Aflatoxin is the same substance that has been found in infant formula in China.
According to the World Health Organisation, it can be found in milk after cows consume feed contaminated by mould and can increase the risk of cancer.
Like much of Europe, Germany has been affected by a growing food scandal, finding horsemeat in several "beef" products and, more recently, discovered that "organically produced" eggs do not conform to the proper standards.