Many of us have an overflowing kitchen cupboard of plastic containers to store our leftovers.
But as awareness grows over the health and environmental pitfalls of plastic, some consumers may be wondering: is it time to ditch that stash of old deli containers?
Only 9% of all the plastic waste ever created has been recycled. From its contributions to global heating and pollution, to the chemicals and microplastics that migrate into our bodies, the food chain and the environment, the true cost of this cheap material is becoming more apparent.
There are thousands of compounds found in plastic products across the food chain, and relatively little is known about most of them. But what we do know of some chemicals contained in plastic is concerning.
Phthalates, for example, which are used to make plastic more flexible and are found in food packaging and plastic wrap, have been found by the Centers for Disease Control and Prevention (CDC) in measurable levels across the US population (including in the body of Guardian journalist Emily Holden). They have been linked to reproductive dysfunction in animal studies and some researchers have suggested links to decreased fertility, neurodevelopmental issues and asthma in humans.
BPA, another chemical widely added to food plastics, has been subject to increasing regulations after studies linked the chemical to neonatal and infant brain and reproductive harm. But BPS and BPF, two common replacements used in products marketed as “BPA-free”, may have similar effects to their predecessor: studies out of both the University of Texas and Washington State University found that even at a dose of one part per trillion, BPS could disrupt cell functioning. A 2019 study from New York University linked childhood obesity with BPS and BPF.
There are many other chemicals added to plastic during production, and researchers concede that many gaps remain in our understanding of how they affect health and development. But research that is adding to concerns about the “miracle material” is growing.
What’s in those takeout containers?
Food containers are just one link in a massive chain of plastic products that touch things we eat, from coated conveyer belts in food production lines to disposable clamshells for delicate berries, clear carrot bags and milk jugs.
Researchers say it is difficult to answer which plastic containers are safe without greater transparency about what chemicals make up everyday plastic materials.
In 2019, the Food Packaging Forum (FPF), a Switzerland-based not-for-profit focused on the science behind food packaging, compiled a database of more than 900 chemicals “likely” associated with plastic food packaging production worldwide and another 3,400 “possibly” used. Of those 4,300 chemicals, 60% did not have any available hazard data, researchers found.
“[The] ‘known knowns’ are the ones I’m going to gravitate to in terms of concern,” said Dr Leo Trasande, director of the Center for the Investigation of Environmental Hazards at New York University’s Grossman School of Medicine, referring to well-known plastic additives such as BPA and phthalates. “The reality is there are many ‘unknown unknowns’ … that may be as problematic.”
In 1988 the plastics industry came up with standardized identification codes for the seven most common types of plastic resin in circulation. Those little numbers found on the bottom of soda bottles and yogurt tubs clue you in to what type of plastic you’re eating or drinking out of. Most food containers – both takeout containers and kinds meant for reuse – are made of low-density polyethylene (4) or polypropylene (5).
Researchers aren’t exactly sure how much chemical exposure occurs from food packaging and storage containers, but they know plastic isn’t a completely stable material. Trasande said that when exposed to heat – for example, in the microwave and dishwasher – polyethylene and polypropylene can break down, leaching unknown chemicals into food and drink. Oily foods are also thought to attract some plastic chemicals.