Too many sodas with caramel coloring can contain a potentially carcinogenic by-product, according to an investigation by Consumer Reports.

"There is a risk in thee that consumers should be informed about," said Dr. Urvashi Rangan with Consumer Reports.

The magazine recently tested 110 samples of soft drinks bought in the New York area and California, including iced tea, root beer, colas and a non-alcoholic malt drink.   The chemical, 4 MEI, which a government study found caused cancer in mice, showed up at varying levels across all brands tested that had caramel coloring.

"Some sodas were actually fairly low in their levels of 4-MEI, whereas some soft drinks were extremely high," Rangan said.

"The highest levels of 4MEI they found were in Malta Goya and Pepsi One.   All of the Coca Cola samples were lower.

"The limitation in this study is a very small sample," Rangan said. "So, we can't really draw conclusions about any one given brand."

Two types of caramel coloring can contain the potential carcinogen. Two other types do not.  However, labels simply say caramel color or artificial color, so consumers don't know which type they are drinking.

"Consumers who want to avoid this hazard should avoid caramel color in sodas altogether," Rangan said.

There are currently no federal limits on 4 MEI in food products.

When contacted by Consumer Reports, Goya said it was looking into the matter. PepsiCo said its products sold in California meet the state's regulations for 4 MEI and it is voluntarily applying those same standards to the rest of the country within the next month.