The US Department of Agriculture (USDA) issued rules on 20 December for the labelling of genetically engineered foods to ensure they are appropriately disclosed, Reuters reports.

“The National Bioengineered Food Disclosure Standard ensures clear information and labelling consistency for consumers about the ingredients in their food,” Agriculture Secretary Sonny Perdue said in a statement. “The standard also avoids a patchwork state-by-state system that could be confusing to consumers.”

Labelling would come into force on 1 January 2020 or a year later for small companies. The mandatory compliance date is 1 January 2022.

Under the new standard, manufacturers, importers and certain retailers must ensure that ‘bioengineered’ foods are disclosed using text, a symbol or an electronic or digital link including QR codes, said just-food. Small food manufacturers or small packages may also such options such as a phone number or web addresses.

Sugar from beet, soyabean oil and other highly processed ingredients were exempted from mandatory labelling.

Reuters said the details of the new standard were more than two years in the making, with consumer groups pushing for more transparency and food companies claiming the labelling system would be costly and confusing.

Some consumer groups had criticised the USDA, saying that the required term “bioengineered” was not a common enough phrase to see on labels, preferring “GMO” or “genetically engineered” instead.