The US Food and Drug Administration (FDA) has introduced a new rule that foods labelled gluten-free must contain less than 20 parts per million of gluten. Additionally, these foods must not contain wheat, rye, barley or any of their cross-bred hybrids, unless the gluten is removed from the grains.

Companies that label their products as free of gluten, without gluten, or no gluten but fail to meet the new requirements will be subject to regulatory action.

The rules were first announced by the FDA last August, giving companies around a year’s time to make the necessary packaging changes.

Prior to this announcement, there were no federal standards or definitions for the food industry to use in labelling products gluten-free.

FDA food labeling and standards director Felicia Billingslea said: "This standard gluten-free definition eliminates uncertainty about how food producers label their products. People with coeliac disease can rest assured that foods labeled gluten-free meet a clear standard established and enforced by the FDA."

People suffering from coeliac disease face potentially life-threatening illnesses on consumption of breads, cakes, cereals, pastas and many other foods that contain gluten.