Recycled and reused food contact plastics are ‘vectors’ for toxins

Nov 28, 2023

Research provides a unique review of contact chemicals in packaging, utensils, plates, etc and how they contaminate food

Recycled and reused food contact plastics are "vectors for spreading chemicals of concern" because they accumulate and release hundreds of dangerous toxins like styrene, benzene, bisphenol, heavy metals, formaldehyde and phthalates, new research finds.

The study assessed hundreds of scientific publications on plastic and recycled plastic to provide a first-of-its-kind systematic review of food contact chemicals in food packaging, utensils, plates and other items and what is known about how the substances contaminate food.

"Hazardous chemicals can accumulate in recycled material and then migrate into foodstuffs, leading to chronic human exposure," the study's authors wrote, noting bottles made from polyethylene terephthalate (PET) plastic as a common example.

The study comes amid a debate over how to reduce the amount of plastic waste filling up the globe. The petrochemical industry, some governments and many environmental groups have pushed for improvements to the recyclability of plastic.

Though some types of the material can be recycled, most cannot, and the study highlights how improving recyclability of the material comes with risks: it identified 853 chemicals used in PET recycled plastic and many of those have been discovered during the last two years.

The most commonly detected were antimony and acetaldehyde, while potent toxins like 2,4-DTBP, ethylene glycol, lead, terephthalic acid, bisphenol and cyclic PET oligomers were also most frequently found.

Moreover, the chemistries of plastics can be something of a black box. In the US, there's very little regulation around what goes in the material and the EU only requires light testing to determine which chemicals are in plastic.

The study characterizes plastics as "very complex materials containing hundreds of different, synthetic compounds which are more often than not poorly characterized for their hazard properties". Some chemicals found in recycled plastics cannot be identified, the analysis notes, adding to the risk of repeatedly recycling and accumulation.

"It's not safe, and as the quality of recycled plastic decreases, the amount of potential contaminants goes up," said Birgit Geueke, the study's lead author and senior scientific officer with the Zurich-based Food Packaging Forum.

The data indicates chemicals are added or created during the recycling process. While 461 kinds of volatile organic compounds (VOCs) were detected in virgin plastic, some 573 were found in recycled material. Geueke said it was difficult to say why that occurred, but it could stem from the addition of chemicals during the recycling process, the addition of chemicals from the contaminated recycling stream, reactions among chemicals, or from plastic taking up additional chemicals when used the first time.

The review also highlighted widespread "illicit" recycling in which industry uses non-food grade plastic made with flame retardants and other toxic compounds in recycled food packaging. Despite strict regulations on which types of plastic can be used for food contact, studies identified recycled electronics in the US, South Korea and European markets.

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"There are clear indications of brominated flame retardants that came from your old TV, computer, keyboard," Geueke said. "It's certainly not legal."

The review identified similar problems with reusable plastic items for food contact, such as kitchen utensils, water bottles, tableware, baby bottles, water dispensers, tubing of milking machines and more.

Food from plastic's first use or detergents used to clean the material can be absorbed and cause chemical changes and contamination in reused material, as can heating it or otherwise using it in a way it is not designed to be.

Consumers can protect themselves by avoiding plastic as much as possible, bringing non-plastic carryout packages to restaurants and moving food products from plastic packaging to containers made of safer materials.

But, ultimately, the most effective remedy is the elimination of plastic and the societal use of safer materials, the study's authors wrote.

"A shift towards materials that can be safely reused due to their favorable, inert material properties could be a promising option to reduce the impacts of single-use food packaging on the environment and of migrating chemicals on human health," the paper states.