The Food and Drug Administration is conducting new studies of the safety of caramel coloring in soft drinks and other foods. Previous research has shown no identifiable health risk.

The agency’s announcement comes in response to a study by Consumer Reports that shows varying levels of an impurity formed in some caramel coloring  in 12 brands of soda from five manufacturers.

The drinks tested were Sprite, Diet Coke, Coca-Cola, Coke Zero, Dr Pepper, Dr. Snap, Brisk Iced Tea, A&W Root Beer, Pepsi, Diet Pepsi, Pepsi One and Goya Malta. Consumer Reports said there was no significant level found in Sprite, and consistently low levels were found in Coke products.

Source: AP