The German Consumer Protection Agency Stiftung Warentest measured aromatic mineral oils in the chocolate of 9 advent calendars, which are suspected to have migrated from the recycled carton of the calendars. Some calendars contained chocolate with mineral oils at levels higher than 10mg/kg of chocolate. The agency suspects the recycled carton out of which the calendars are made to be the culprit. Recycled paper often contains residues of printing inks containing mineral oils but also the newly printed Christmas motives may be partially responsible. Aromatic mineral oils are thought to be carcinogenic. The other types of mineral oils present in the advent calendars have been shown to cause inflammation in the liver in animal studies. Overall, Stiftung Warentest had found mineral oils in every single one of the 24 advent calendars tested and further encountered benzophenone in one calendar.
Stiftung Warentest (in German)
Federal Institute for Risk Assessment (BfR) (in German)