LONDON • Burnt toast, overcooked potatoes and too much browning of other starchy foods raises the threat of cancer for the consumer, according to new research.

The UK Food Standards Agency (FSA) says the risk comes from acrylamide - a chemical compound that forms in some foods when they are cooked at above 120 deg C. The chemical has been shown to cause cancer in animals, and scientists believe it may also do so in humans.

The FSA said that means eating potatoes and bread that have been roasted, fried or grilled too long at high temperatures could be risky. It suggests cooking to a golden yellow colour because overbrowning produces acrylamide. The darker the colour, the more acrylamide.

Sugar, amino acids and water in the foods combine to create colour, flavour - and acrylamide.

Cutting potatoes into larger wedges reduces their surface area, thereby cutting down the level of acrylamide that can form. Crinkle-cut chips are worse than normal chips as they have a larger surface area, Britain's The Independent reported.

The FSA warning covers foods that are high in starch, with the main one being potatoes, including sweet potatoes. But the FSA said other root vegetables, cereals - not porridge but including baby foods that are cereal-based - bread, crackers, biscuits and even coffee are included in its warning.

FSA director of policy Steve Wearne said that boiling, steaming or microwaving could limit browning and reduce acrylamide levels.

Consumers are also advised not to keep raw potatoes or parsnips in the refrigerator as this can increase acrylamide levels. Instead, they should be stored in a cool, dark place at a temperature of above 6 deg C.

Smokers are also exposed to three to four times more acrylamide than non-smokers because the chemical is present in tobacco smoke, said BBC News.

The new warning is not related to earlier reports targeting burnt, barbecued meat, which scientists have said raises the risk of cancer because of a substance called benzopyrene.