Bread, biscuits, crisps and french fries, foods frequently eaten by millions of people around the world, contain alarmingly high quantities of a cancer-causing chemical, according to Swedish research released this week.
The research carried out at Stockholm University in cooperation with experts at Sweden's National Food Administration, a government food safety agency, showed that heating carbohydrate-rich foods, such as potatoes, rice or cereals formed acrylamide, a substance classified as a probable human carcinogen, reports Reuters.
Indeed, the research was deemed so important that the scientists took the unusual step of going public with their findings before the research had been officially published in an academic journal.
``I have been in this field for 30 years and I have never seen anything like this before,'' said Leif Busk, head of the food administration's research department. Findings revealed at a news conference called by the food administration showed that an ordinary bag of potato crisps may contain up to 500 times more of the substance than the top level allowed in drinking water by the World Health Organisation (WHO).
French fries sold at Swedish franchises of US fast-food chains Burger King and McDonald's contained about 100 times the one microgram per litre maximum permitted by the WHO for drinking water, the study showed. One milligram, or 0.001 grams, contains 1,000 micrograms.
The US Environmental Protection Agency classifies acrylamide, a colourless, crystalline solid, as a medium hazard probable human carcinogen.
According to the International Agency for Research on Cancer, acrylamide causes gene mutations and has been found in animal tests to cause benign and malignant stomach tumours.
It is also known to cause damage to the central and peripheral nervous system.
``The discovery that acrylamide is formed during the preparation of food, and at high levels, is new knowledge. It may now be possible to explain some of the cases of cancer caused by food,'' Busk said. ``Fried, oven-baked and deep-fried potato and cereal products may contain high levels of acrylamide,'' the administration said.
It explained : ``Acrylamide is formed during the preparation of food and occurs in many foodstuffs...Many of the analysed foodstuffs are consumed in large quantities, e.g. potato crisps, french fries, fried potatoes, biscuits and bread.''
Among products analysed in the study were potato crisps made by Finnish company CHIPS ABP, whose shares fell 14.5 per cent to six-month lows, as well as breakfast cereals made by US Kellogg, Quaker Oats (part of PepsiCo), and Nestle and Old El Paso brand tortilla chips.
``For us, these are completely new findings which have never before been known to the world's foodstuffs industry,'' CHIPS ABP said in a statement to the Helsinki stock exchange.
Stefan Eriksson, marketing manager of Burger King's subsidiary in Sweden, told Reuters :``We have received the information and we are evaluating what it will mean.''
Spokesmen for the other companies mentioned in the research were not immediately available for comment.
Margareta Tornqvist, an associate professor at Stockholm University's department of environmental chemistry, said the consumption of a single potato crisp could take acrylamide intake up to the WHO maximum for drinking water.
Busk said, however, that the product analysis based on more than 100 random samples was not extensive enough for the administration to recommend the withdrawal of any products from supermarket shelves.
``Frying at high temperatures or for a long time should be avoided,'' Busk said, adding: ``Our advice to eat less fat-rich products such as french fries and crisps, remains valid.''
He said the findings applied worldwide, not only to Sweden, as the food raw materials used in the analyses had shown no traces of acrylamide. Swedish authorities had informed the European Commission and EU member countries, Busk said.
``It is the first time we have come across such a result. We will evaluate this study and look at it but it is important to say that Sweden has not withdrawn any products from the market,'' said European Commission spokeswoman Beate Gminder.
``Therefore we'll have to see what the scientific evaluation by our side and by scientists in the member states will bring about,'' she said.
Liliane Abramsson-Zetterberg, a toxicologist at the Swedish food administration, said: ``The cancer risk from acrylamide is much higher than (the levels) we accept for known carcinogens.'' But she added that smoking, a well-known cause of cancer, remained a bigger risk.