In a paper published in the Journal of Epidemiology and Community Health, researchers noted that exposure to food-contact materials (FCMs) could be a “cause of concern for several reasons'', Fox News reports.

Over 4,000 chemicals are suspected to be used in FCMs, including some known-carcinogens, such as formaldehyde. And according to the paper’s authors, these synthetic chemicals may be capable of leaching into food.

Currently, toxicology tests on food products don’t test for cellular changes that might be caused by FCMs. The researchers are urging more study into the effects of chemicals used in FCMs.