Crispy roast potatoes, crunchy chips and well-done toast may taste delicious, but they can also contain high levels of a cancer-causing chemical, a new report warns.
In a new study, The Food Standards Agency (FSA) tested the amount of acrylamide present in common foods.
Acrylamide is a chemical produced through cooking and is classed by the FSA as a "genotoxic carcinogen" because it "has the potential to cause cancer by interacting with the genetic material (DNA) in cells".
The researchers found that the crispier the roast potato, chip or slice of toast, the higher the acrylamide level.
The research team took samples of toast and potatoes from 50 households in order to test acrylamide levels.
They found that bread toasted to the palest colour contained just 9 micrograms of acrylamide per kilogram. In comparison, toast cooked to the darkest colour contained almost 19 times more acrylamide at 167 micrograms per kilogram.
The researchers saw similar results when testing chips and roast potatoes.
The most well-cooked batch of chips was found to contain 1,052 micrograms of acrylamide per kilogram - 50 times higher than the palest chips.
The crispest roast potatoes were found to contain 490 micrograms of acrylamide per kilogram - 80 times higher than the least cooked roast potatoes.
Professor Guy Poppy, the FSA’s chief scientific adviser, commented: "The risk assessment indicates that at the levels we are exposed to from food, acrylamide could be increasing the risk of cancer."
He added that while the FSA is not advising people to stop eating particular foods, it recommends that chips are cooked "to a light golden colour" and "bread should be toasted to the lightest colour acceptable".
The report also advises members of the public to avoid "fluffing" up parboiled potatoes in the pan when making roasties.
"For roast potatoes, the deliberate fluffing up (shaking parboiled potatoes in a pan) that was witnessed on a few occasions is a deliberate attempt to increase surface area. Participants’ aim for this process is for cooked potatoes to be crispier (i.e. through more oil or fat being absorbed)," it states.
"The increased surface area may lead to greater acrylamide generation."
The report comes after the World Health Organisation warned that processed meats such as bacon and sausages are as big a cancer threat as cigarettes last month.
The report found eating 50g of processed meat a day (one sausage or two rashers of bacon) can increase an individual's chance of developing bowel cancer by nearly 20%.