Consumer testing institute Stiftung Warentest said last week it had found mineral oils from packaging in chocolates from such calendars - and that in nine cases the Christmas treats were so badly contaminated that children should not eat them.
Now consumer watchdog Foodwatch says the Agriculture and Consumer Minister Ilse Aigner deliberately failed to publish the results of a study she had commissioned, which showed that potentially dangerous chemicals could be found in the packaging of food like rice, cake mixtures and breakfast oats.
These chemicals could be transferred to the food, the study conducted by a group of institutions including Stuttgart's chemical and veterinary investigation office and Dresden Technical University. The Tagesspiegel newspaper said on Tuesday that the group alleged the report had been withheld since May.
The researchers found 250 substances in food packaging - including carcinogenic chemicals. These were mostly found in packaging made from recycled paper - because that comes from old newspapers, catalogues and other packaging, which has often been printed with oil-based inks. This creates the situation where such chemicals can contaminate food.
The Federal Institute for Risk Assessment, and the Agriculture and Consumer Ministry are pushing for the levels of mineral oils in food packaging to be reduced as far as possible, the Tagesspiegel said.
It said Aigner had introduced two measures over the past fortnight to set limits on the level of acceptable contamination of food, and to institute a ban on oil-containing inks for food packaging in general. "No other country in the European Union is doing anything apart from us," Aigner's spokesman told the paper.
He also denied that the ministry had failed to publish the report on contamination, saying it had been publicly available on the internet.