The big four supermarkets have disputed a report from environmental group Friends of the Earth claiming their own label tortilla chips contain GM ingredients not approved for consumption in the UK. Friends of the Earth commissioned German lab GeneScan to test products containing maize such as corn chips and cereals. Tortilla chips at Asda and Safeway tested positive for Monsanto's GM maize GA21, while Tesco and Sainsbury's chips contained fellow US biotech giant Dekalb's GM maize DBT 418. None of the products have been recalled, although each supermarket is conducting its own investigations. Asda has no plans to take the chips off shelves: "We're very vocal about our non-GM commitment," said a spokeswoman. "The report took us by complete surprise." Tesco said: "Even FoE said the results are contradictory. We're analysing them properly using tests approved in the UK." Sainsbury said: "Our maize is grown by non GM firms, ground at a dedicated non-GM mill, tested by an independent laboratory when it's made into flour, and tested again when it arrives in store." Safeway said it was taking the report "very seriously," but had no plans to recall the items. {{NEWS }}