Children might love colorful candy, but the azo dyes typically used to make the bright hues contain armful additives, according to the Frankfurt-based Consumer Protection Office in the German state of Hesse.

Additives include tartrazine, carmoisine and quinoline yellow. These dyes not only cause allergic reactions, but they are also believed to cause intensify hyperactivity in children, making difficult for them to concentrate.

There are similar concerns about the food additive, benzoic acid. There are also concerns that the coloring quinoline yellow could be carcinogenic.

Common in supermarkets

A study conducted by the state's Consumer Protection Office found that 44 percent of the supermarkets visited in Frankfurt had food products with azo dyes. Three percent of the food products aimed at children, and drink products in particular, also contained benzoates as preservatives.

According to EU regulations, such products will have to have a warning notice on their packaging by 2010. The states' Consumer Protection Office has called for a complete ban on these additives.