People with nut allergies could still be at risk when they eat "peanut free" Indian takeaway meals, according to a new study in Lancashire.
People have died after eating peanuts in takeaway curries
Researchers found eight of 20 such meals contained peanut extracts - despite the buyers in each case making it clear the food must not contain any.
Lancashire Trading Standards Department carried out the study.
The Anaphylaxis Campaign says up one in 70 Britons may have a nut allergy, which in its worst form can kill.
Chief Trading Standards Officer Jim Potts said: "The peanut source may be cooking oils, nut powders or simply cross contamination in busy take-away kitchens where nut product ingredients are present.
"The restaurant owners themselves may be unaware of the problem as one ingredient ordered as 'almond powder' resulted in a delivery of nut powder which also contained peanuts."
The deputy leader of Lancashire County council, Doreen Pollitt, said: "We are warning anyone suffering from severe peanut allergy to be aware of take-away meals.
"Severe reaction and even deaths have occurred from sufferers consuming take-away meals with peanut ingredients and we want to minimise this risk.
"Our Trading Standards Service are taking steps to bring the problem to the notice of take-away chefs and owners and to ensure their ingredients and cooking methods minimise the risks."
Hazel Gowland of the Anaphylaxis Campaign said: "Most allergy deaths are caused by an allergen ingredient, unrecognised by the food supplier and or the consumer.
"That is why the kind of testing Lancashire County Council is doing is so important"