A study into processed foods by researchers at McGill University has shown how the volatile, and possibly carcinogenic, chemical furan is produced in some foods as a byproduct of the packaging process. Health Canada and the U.S. Food and Drug Administration have found furan, a chemical with a number of derivatives, to be present in processed foods.

Researchers at McGill University have shown how food-based amino acids and sugars break down when they are heated to produce furan.

"We found out that the different sugars and different amino acids in foods can break down by heat or cooking and we studied the mechanism of how furan forms during processing," said Dr. Varoujan Yaylayan, a food chemistry professor at McGill.

The study also looked at other food components, such as vitamin C and polyunsaturated fatty acids, which may also produce furan as an unwanted by-product of cooking, bottling or canning food products.

SEALED IN CANS

"Normally, furan is a volatile chemical which tends to quickly evaporate. However, when it cannot escape for some reason -- for example, if it's in sealed cans or jars -- then it remains present in the food for some time," Yaylayan said.

While traces of furan and furan-containing products have been found in some processed and cooked products -- especially canned and bottled foods -- there's no reason for consumers to change their shopping habits.

"There is no direct evidence that furan is carcinogenic, but it's known in animal models to be carcinogenic, so it is possible it could also be a human carcinogen," Yaylayan said.

The quantities of furan in foods are well below what are considered dangerous.

Many food companies, Health Canada and the FDA are conducting studies.

Furan levels do not directly equate to exposure to the chemical. Estimation of exposure levels requires consideration of furan levels in a particular food and the amounts of that food that a consumer eats.

The study is published in the journal Agriculture and Food Chemistry.