burnt toast acrylamide

Forget bacon - burnt toast is the new cause célèbre when it comes to carcinogenic controversies.

The UK’s food watchdog was accused of “nanny-stateism” this week for suggesting Brits should strive to avoid burning bread - and other starchy carbs - to reduce the risk from toxic chemical acrylamide.

It’s not the first time Brits have faced warnings over its link to cancer. So why has the FSA put the spotlight back on acrylamide? What is the actual risk to consumers? And should food manufacturers be worried about the increased focus from regulators?

The European Food Safety Authority drew public attention to the dangers of burnt toast in 2014, when its draft scientific opinion concluded acrylamide in food was a probable cancer risk for all age groups. A year later, the FSA’s chief scientific advisor Professor Guy Poppy flagged up the issue again after a study found Brits still had very little awareness of the chemical and were charring toast and overcooking roast potatoes with reckless abandon.

The agency decided to step up efforts to educate consumers with its ‘Go for Gold’ campaign after its latest Total Diet Study, published this week, confirmed fears that UK dietary exposure to acrylamide is higher than EU food safety chiefs deem safe.

Acrylamide, a chemical compound that forms naturally in starchy carbs when they are heated at temperatures above 120°C, was discovered in food by Swedish scientists in 2002.

The discovery initially raised alarms because acrylamide - which has a wide range of industrial applications including the production of plastic - has known toxic effects on the nervous system and on fertility.

In June 2002, a WHO and FAO report concluded dietary intake of the chemical would not be high enough to cause these effects, but raised concerns over its potential as a carcinogen, based on animal studies.

Scientists have never been able to establish that acrylamide is carcinogenic for humans, admits Gavin Shears, a senior policy adviser in contaminants at the FSA. Critics argue that acrylamide has only been shown to cause cancer in rats. But that doesn’t mean it is nothing to worry about.

“Acrylamide has been shown to be a genotoxic carcinogen in animals. Because it works by interacting with DNA, it is considered to be a probable human carcinogen,” says Shears.

The WHO’s International Agency for Research on Cancer has listed it as a Group 2A “probable carcinogen” alongside red meat and, after reviewing all the scientific evidence to date, EFSA also believes it is most probably carcinogenic.

Acrylamide: an accidental discovery


The discovery of acrylamide has its roots not in food science but in construction, says Dr Simon Cotton, senior chemistry lecturer at the University of Birmingham.

Twenty years ago, workers were building a railway bridge through the Hallandsås ridge on the Bjäre peninsula in southern Sweden when cows in the surrounding area began collapsing and, in some instances, dying. The subsequent investigation showed water in the surrounding streams had become contaminated by acrylamide, which originated from polyacrylamide used as a crack sealant in the tunnel.

When scientists studied the tunnel workers’ exposure to acrylamide, they found that not only did the workers have unsafe levels of the chemical in their blood, but so did the control group of people who had no known exposure.

This prompted them to look at food as a potential source. While scientists initially suspected burgers, they found high levels of acrylamide in fried potatoes, as well as coffee.

“We know now acrylamide is associated with carbohydrate-rich foods that have been heated above 120°C - that is food that has been fried, roasted or baked,” Cotton says.


No safe level

Establishing the exact risk from foods is tricky. While for some food contaminants you can establish a ‘safe’ maximum intake, it is not possible to do so with a genotoxic carcinogen like acrylamide. “So theoretically there is no safe level of exposure,” Shears says.

The EFSA therefore takes a margin of exposure approach.

“EFSA has advised that on the basis of the animal studies and other data they reviewed, a margin of exposure of 10,000 or greater would be of low concern,” says Shears. “The margin of exposure to acrylamide in the UK diet is in the range of 300 to 59. Which means it is of concern.”

Given that acrylamide is present in so many foods, and naturally occurs during the cooking process, eliminating it from our diets would be almost impossible. “We have to be realistic about what we can do,” says Shears. “So we have chosen to be open with the evidence and advise consumers on how to reduce the risk.”

It is possible to reduce acrylamide exposure by cooking food for less time (making chips a light brown colour instead of the crispy, blackened variety) but that is only one part of the puzzle. Processed foods including crisps, oven fries, coffee, biscuits, crackers, crisp bread and even soft bread have been found to contain acrylamide.

And this could have implications for food manufacturers. In 2005, acrylamide hit the headlines in the US after California’s attorney general sued a number of food manufacturers and foodservice establishments for selling French fries and crisps containing high levels of acrylamide and failing to provide warnings.

The lawsuit resulted in food processors including Kettle Foods, Frito-Lay and Procter & Gamble agreeing to reduce acrylamide levels in their products. And restaurant chains including KFC, McDonald’s, Wendy’s and Burger King also agreed to post acrylamide warnings in their restaurants.

UK manufacturers have no such fears of prosecution, says Shears. Although the FSA is running ongoing surveillance of acrylamide levels in supermarket food products, there is currently no regulatory framework in place to control levels of the chemical in food.

acrylamide scale

“Since 2010 we have had indicative values agreed for acrylamide in the EU. If samples taken by member states exceed the IV, it triggers an investigation of the food business by local authorities, who check their understanding of acrylamide and what action has been taken to mitigate it,” he explains. “But it is not enforcement action and does not mean that product is not safe to eat.”

But food manufacturers are still taking the issue seriously. McDonald’s has already announced it is taking steps to reduce acrylamide following the FSA announcement. Helen Munday, FDF chief scientific officer, says reduction is a sensible strategy.

“At the end of the day we just don’t know whether acrylamide increases the risk of ill health, including cancer, in humans,” she says. “But rather than go forward to a point where the potential risks crystallise, we think the better way forward is to minimise all presence of it and prevent those risks from ever occurring.”


She claims the Acrylamide Toolkit developed by FoodDrinkEurope, which sets out potential mitigation measures, has helped some of the worst affected sectors make significant progress on reducing levels of the chemical.

Indeed, a FoodDrinkEurope study of 20 European countries including the UK showed more than a 50% reduction in acrylamide levels in potato crisps. “The proportion of samples exceeding the indicative value has gone from nearly 24% to just over 3%,” says Munday. “That is really good progress.”

The FSA’s latest two years of surveillance data also shows a 55% reduction in pre-cooked chips - though Shears warns the relatively small sampling size means these results should be viewed with caution.

There could also be some legislation ahead - the FSA is discussing a potential legal framework for acrylamide with the European Commission - but this is most likely to focus on embedding the codes of practice developed with the industry into the food chain.

The FSA is “fully supportive” of this approach, adds Shears, and has no plans to pursue more draconian measures. “We think this is moving in the right direction.”