Recent accusations that certified organic cotton from India may contain genetically modified organisms (GMO) have prompted a textile testing agency to highlight that cotton can be screened for genetic modification.

While the global market share of organic cotton is on the rise, its higher market price can only be justified if organic cultivation is verified.

For cotton to be considered organic, the use of genetically modified plants is prohibited. In spite of this, genetically modified organisms (GMOs) are repeatedly found in textiles allegedly produced from organic cotton, for reasons that include contaminated seeds, cross pollination during cultivation, and contamination of cotton fibres during processing.

The Hohenstein Institute in Boennigheim, Germany says its laboratory testing can verify whether cotton and cotton-based end products are genuinely organic or contain genetic modifications.

Its detection systems were specifically designed for textile products, and testing can be carried out on raw cotton, yarns and fabrics, as well as ready-made items.

The GMO testing consists of two steps. First the sample is crushed and cotton fibres are mechanically and enzymatically digested. The genetic material (DNA) is then isolated from the fibres and purified through a multi-stage process.

If a specific target sequence (marker gene) is found in the DNA, this indicates a genetic modification that is confirmed by molecular biological evidence. Control reactions serve to verify unaltered cotton DNA and also to exclude an inhibition of the detection reaction.

Brands and manufacturers offering organic cotton products are among those who would benefit from GMO screening, as well as certification organisations wishing to label the cotton as organic, and consumer protection agencies.

German organic fashion brand Cotonea last month raised concerns that Global Organic Textile Standard (GOTS) certified cotton from India contains GMO.

GMO cotton was first cultivated in India in 2002, and now accounts for more than 90% of the country's crop. But there have long been concerns that manipulated genes would mix with non-manipulated plants through cross pollination.

Call for GOTS to investigate GMO India cotton claims