The term 'natural' is used on many different foods, but it is not always clear what it actually means, unlike the term 'organic' which is strictly regulated.

The FDA said that a formal definition of the term had not been established. However, the FDA currently considers the term “natural” to mean that nothing artificial or synthetic (including all colour additives regardless of source) has been included in, or has been added to, a food that would not normally be expected to be in that food.

But the regulator said this policy did not take into account food production or processing methods, such as the use of pesticides, thermal technologies, pasteurisation, or irradiation. The FDA also did not consider whether the term “natural” should describe any nutritional or other health benefit.

The FDA said it is taking action because it received three Citizen Petitions asking that the agency define the term “natural” for use in food labelling and one Citizen Petition asking that the agency prohibit the term “natural” on food labels.

Court cases had also resulted in a need to define whether food products containing ingredients produced using genetic engineering or foods containing high fructose corn syrup may be labelled as 'natural'.

Interested parties can comment on the use of a 'natural' label by going to http://www.regulations.gov and typing FDA-2014-N-1207 in the search box.