Cups, boxes, utensils: should you get rid of plastic in your kitchen?

Plastic containers, utensils, cutlery, plates, glasses, molds, and even household appliances—food processors, kettles, blenders, steamers, and mincers—are made of plastic. Since the first petroleum-derived plastics were synthesized a hundred years ago, plastic has become a staple in the kitchen.

But what do these plastics contain, used to prepare, cook, reheat, or store meals? Plastics are composed not only of polymers (a chemical substance composed of large molecules) "but also of a mixture of different additives, which give the plastic properties: flexibility, rigidity, and fire resistance," explains the French National Agency for Food Safety (ANSES).

Should we be wary of them? "Polymers intended for food-related uses contain fewer additives," Jean-François Gérard, professor at INSA Lyon and deputy scientific director of the CNRS Chemistry Institute, told BFMTV.com.

"These are only validated and authorized polymers that meet standards, particularly within the European Union."

But he acknowledges that there is "never zero danger." This is particularly true because these polymers degrade over time. "We know that when they degrade, they release tiny particles: micro- and nano-plastics, which also release additives," Mathilde Body-Malapel, a researcher specializing in immunotoxicology at the University of Lille, points out to BFMTV.com.

Additives presented as "potential chemical contaminants" by ANSES. "All of them can be toxic," adds Mathilde Body-Malapel, a specialist in pollutants affecting human health. The best known are bisphenols and phthalates, proven endocrine disruptors. But there are many others.

"For some of the chemical compounds added to plastic, their toxicity has been very little studied."

The Parliamentary Office for the Evaluation of Scientific and Technological Choices (OPECST), composed of MPs and senators, mentioned in a report on the impacts of plastics on human health published last November a total of 4,000 chemicals, out of the 16,000 identified, that "can be classified as hazardous." With human contamination that appears significant: "25% of the 14,000 chemicals contained in plastic materials in contact with food have been identified in the human body," writes the office.

The report also highlights the carcinogenic, mutagenic, and reprotoxic nature of these substances, as well as their links to genital malformations in newborns, delayed or impaired cognitive development in children, and their toxicity to certain organs, type 2 diabetes, and obesity. "The shortcomings in the assessment of chemical substances lead to an underestimation of their dangerousness," the authors warn.

"Microplastics are present in all human organs and accumulate there."

Because the substances contained in a plastic object are indeed likely to be released into the food or drink it contains. Mathilde Body-Malapel speaks of a "small degradation," which means a small contamination, with each use. "These are traces in minimal quantities that are found, but they are traces of nanoplastics nonetheless."

"Traces, more traces, more traces, it can end up with potentially toxic quantities."

Contamination that occurs in "ordinary" everyday situations, continues researcher Mathilde Body-Malapel. A plastic cup placed in a cooler full of ice cubes, microwave cooking—"even with so-called microwaveable containers," she explains—or even a meal delivered in a cardboard container.

Because in the latter case, the container isn't just cardboard. It's often coated with polylactic acid—called PLA—a polymer made from plants. And according to a study published by the Institut Polytechnique de Paris, the toxicity of these bioplastics is equivalent to that of ordinary plastics made from petroleum.

"Toxicity is minimized," reassures Jean-François Gérard, also director of the CNRS's recycling, recyclability, and reuse of materials program. "The additives (in food containers, editor's note) are designed to prevent migration." But while he asserts that these migrations remain "under control," he acknowledges that problematic compounds can indeed form "during use, with degradation, scratches, aging, or passages under a scouring sponge."

But the main problem, according to him, remains the misuse of these plastic containers. For example, a container that comes out of the microwave deformed, a box whose bottom takes on the color of the food it contains, a non-stick pan that becomes sticky... "This means that the nature of plastic has changed."

"We know the toxicity of each substance well, but depending on how consumers use it, it can be extremely different."

However, some situations do not constitute misuse. Some compounds in these plastics are soluble in oil, while others are soluble in water. They can therefore contaminate food without the user having misused these plastics.

Bottled water is proof of this: a study has shown that it contains an average of 240,000 detectable plastic fragments per liter, or nanoplastics so small that they are capable of penetrating organs. These fragments are thought to come primarily from the bottle itself.

"We also don't know the cocktail effects of these additives," that is, the effects they can have when combined with each other, points out Mathilde Body-Malapel, who has notably studied the effect of microplastics ingested via food on the intestine.

What OPECST also denounces: "information concerning their persistence, bioaccumulation or mobility is more difficult to find since these criteria are not always included in government assessments."

Recently, a U.S. study highlighted the presence of flame-retardant chemicals in black plastic kitchen utensils. This toxic presence could be explained by the recycling of plastics from electronic devices that originally contained flame retardants.

For Jean-François Gérard, it's unlikely that this kind of situation will occur in France—plastic from electronic devices cannot end up in food-grade plastic, he says. But he acknowledges that plastic recycling still raises questions.