Genetically modified food could soon contain a DNA barcode to make it easily identifiable, thus helping regulators to recognise food or crops that have been contaminated with GM material.

The National Institute of Agricultural Botany (NIAB) in Cambridge, UK, was granted a patent this week on a DNA bar-coding technique, reported the New Scientist magazine.

The technique works by adding a unique DNA sequence to all GM organisms so that a simple DNA test would identify any product as genetically modified if it contains that sequence. The DNA sequence would be one that does not code for any protein and would therefore not alter the plant’s properties.

A spokesman for Britain’s Department for Environment, Food and Rural Affairs (DEFRA) said it was too early to commit to any one method, but told New Scientist that such technology would be “actively encouraged”. A recent European Union directive gives governments the power to make it compulsory.

“We have been talking about techniques for encoding unique identifiers in the context of GMOs for some time,” says Howard Dalton, DEFRA’s chief scientific adviser. “Any development which would help in the process of detecting and identifying GMOs would be welcomed.”