Researchers at the University of Glamorgan in Wales tested 25 soya foods bought from health food stores and supermarkets for the presence of GM ingredients. Forty per cent, or 10 of those tested, contained GM ingredients.
The researchers said this was surprising because eight out of the 10 GM-positive samples were either labelled as 'GM free' and/or were labelled as 'organic', both of which imply absence of GM ingredients.
The team said current labelling practices that may be misleading about the presence of GM ingredients in many organic and vegetarian foods should be reconsidered in the interest of consumers.
Soya is a key ingredient in many organic and health foods and has also become a widely consumed ingredient in more mainstream foods. A report published last year by the Prosoy organisation said that per capita consumption of soya-based drinks and desserts in Europe has grown by over 20 per cent in 2002 and is currently as large (valued at €1.3 billion) as the consumption of meat-free and tofu products.
"We have recently observed that many soya products now carry 'GM free' or 'organic' labels, both of which imply an absence of GM ingredients in these foods," said Professor Denis Murphy, head of the biotechnology unit at Glamorgan university.
"However, most of the soya now produced in the world comes from GM varieties. Nearly all our soya is imported from the USA (80 per cent GM), Argentinean (95 per cent GM), and Brazilian (over 30 per cent GM and growing)."
One food tested by the researchers, a vegetarian sausage mix that was labelled 'GM free', contained 0.7 per cent GM soya. This is close to the 0.9 per cent mandatory EU threshold that would require it to be labelled as a GM product.
Three other foods contained 0.1-0.4 per cent GM soya; this is above the limit for organic foods, required by the UK organic certification body the Soil Association.
"Given that GM soya production is set to increase even more over the coming years, it is difficult to see how 'GM free' labels can be justified unless there is much more rigorous testing of such foods," continued Professor Murphy.
"In view of these findings, the organic food industry may need to reconsider the 0.1 per cent threshold for GM presence in organic foods; an alternative is to remove organic status from all soya products, unless these have been rigorously tested for GM," he added.
The study, conducted in South Wales and Yorkshire during the summer of 2003, used an EU-approved method, called an ELISA, to detect any GM proteins.
A full account of the complete study will be published on 2nd April, in the British Food Journal (Vol 106 (3) 2004).