The Center for Science in the Public Interest (CSPI) is again at odds with the US soft drinks industry, this time over the safety and labelling of caramel colouring 4-MI.

The US consumer body has petitioned that Food & Drug Administration (FDA) to force companies to rename 4-methylimidazole (4-MI) on labels to flag up its chemical composition. Currently, companies are simply allowed to refer to "caramel colouring", it said.

In addition, CSPI said today (5 March) that commissioned laboratory tests on Coca-Cola and Pepsi-Cola found 4-MI in drinks above levels that would require regulatory intervention in the state of California. The drinks tested were bought in Washington DC. The CSPI also cited animal studies as showing that 4-MI raises the risk of some cancers in animals.

The American Beverage Association (ABA) issued a strong rebuttal of the CSPI's claims. "This is nothing more than CSPI scare tactics, and their claims are outrageous," it said today. "The science simply does not show that 4-MEI [sic] in foods or beverages is a threat to human health."

Currently, the FDA treats 4-MI as 'generally recognised as safe', or GRAS, while neither the European Food Safety Authority nor Health Canada have found health risks associated with the colouring. Criticising the stance of California, the ABA said: "A person would need to drink more than 2,900 cans of cola every day for 70 years to reach the lowest dose levels mice received in the single study upon which California based its decision."

A spokesperson for The Coca-Cola Co added: "The 4-MEI levels in our products pose no health or safety risks."