acrylamide, a carcinogen, has been found in many foodstuffs available in the us markets. The toxic substance is formed in starchy foods when they are fried or roasted at high temperatures.

No one suspected it was so pervasive in food until 2002, when scientists of Sweden-based Stockholm University found that French fries sold at Swedish franchises of McDonald's and Burger King contained acrylamide about 100 times more than the World Health Organization's limit for water.

Since then a few countries have conducted tests to gauge acrylamide levels in foodstuffs. During its latest assessment, the us Food and Drug Administration analysed 750 different products. It found no acrylamide in processed cheese, milk and ice cream. But relatively high levels were found in arrowroot cookies, teething biscuits and sweet potatoes. Other childhood favourites such as peanut butter and chocolate chip cookies were also contaminated.