London: Chips served in many fast-food outlets and restaurants contain acrylamide – the chemical that has been linked to cancer because of the cooking process– scientists have warned.
They found that potatoes, which have been part-cooked before sale and then quickly reheated before serving, contain increased levels of the substance.
A study by researchers at Reading University found acrylamide is present in chips, which have been dried, frozen and cooked twice before reaching the table, a common form of preparation.
This method is used to make shoestring fries, the thin chips widely sold in thousands of fast-food restaurants and takeaways across the country.
Acrylamide is a carcinogen. It is present in a wide range of foods such as biscuits, breads, crisps and chips that have been baked, fried or grilled at temperatures higher than 120C.
The new report, published in the Journal of Agricultural and Food Chemistry, has sparked warnings for restaurants not to over-cook chips as the substance has been detected in potatoes and starch-rich foods, which have been heated for long periods.
It urges the food industry to modify how it prepares potatoes for sale to restaurants and takeaways.
“There is continuing concern about acrylamide, but this research highlights what we can do to reduce the presence in potato products,” the Daily Express quoted food chemist Professor Donald Mottram, who carried out the research, as saying.
“There is prior treatment of potatoes which can reduce the levels and the food industry will be alerted to these findings. However, it will be very difficult to eliminate it completely,” he noted.
The commercial process includes potato selection and sorting, cutting, blanching, sugar augmentation, drying, frying and freezing, he explained.
In combination with final cooking, this generates the colour, texture and flavour that consumers expect in French fries, he added.
The risk can be lowered by not over-cooking chips, said Barbara Gallani, director of food safety and science at the Food and Drink Federation.
“Acrylamide levels can be limited if chips are cooked to a light golden colour and not over-cooked. It is therefore important to follow the manufacturer’s cooking instructions,” she stated.
Carcinogens in potatoes have been linked to an increased risk of cancer, specifically breast cancer, endometrial cancer and cancer of the womb.