A US non-profit health watchdog claims guidelines surrounding the labelling of food with artificial colourings are deceiving consumers.

The Center for Science in the Public Interest says food and drink manufacturers are labelling their products with references to fruit and vegetables, even though they don't contain any.

It used the example of General Mill's Betty Crocker Carrot Cake Mix, which the watchdog claims has no carrots, but carrot-flavoured pieces made with corn syrup, flour, corn cereal, partially hydrogenated cottonseed and/or soybean oil, a small amount of carrot powder and artifical colours.

The CSPI has sent the US Food and Drug Administration (FDA) a regulatory filing asking them to require food companies to disclose on the front of food labels whether a product is artificially-coloured.

"Betty Crocker is certainly free to make virtually carrotless carrot cake," said CSPI executive director Michael Jacobson.

"But consumers shouldn't have to turn the package over and scrutinise the fine print to know that the colour in what are mostly junk foods comes from cheap added colourings."

Spokespeople from General Mills and the FDA were not available for comment at time of going to press.