The government has long known that tiny amounts of chemicals used to make plastics can sometimes migrate into food. The Food and Drug Administration regulates these migrants as â€œindirect food additivesâ€ and has approved more than 3,000 such chemicals for use in food-contact applications since 1958. It judges safety based on models that estimate how much of a given substance might end up on someoneâ€™s dinner plate. If the concentration is low enough (and when these substances occur in food, it is almost always in trace amounts), further safety testing isnâ€™t required.
In a study published last year in the journal Environmental Health Perspectives, researchers put five San Francisco families on a three-day diet of food that hadnâ€™t been in contact with plastic. When they compared urine samples before and after the diet, the scientists were stunned to see what a difference a few days could make: The participantsâ€™ levels of bisphenol A (BPA), which is used to harden polycarbonate plastic, plunged â€” by two-thirds, on average â€” while those of the phthalate DEHP, which imparts flexibility to plastics, dropped by more than half.
The findings seemed to confirm what many experts suspected: Plastic food packaging is a major source of these potentially harmful chemicals, which most Americans harbor in their bodies. Other studies have shown phthalates (pronounced THAL-ates) passing into food from processing equipment and food-prep gloves, gaskets and seals on non-plastic containers, inks used on labels â€” which can permeate packaging â€” and even the plastic film used in agriculture.