Microplastics in food and the kitchen

Rule one: heat is the multiplier

Strong Across almost every study, warmer temperatures mean more particles. When researchers at the University of Nebraska–Lincoln microwaved polypropylene baby-food containers and a polyethylene pouch for three minutes, some released more than 2 billion nanoplastics and around 4 million microplastics per square centimeter of plastic. Hot water, acidic foods and fatty foods all increased the release. Room-temperature and refrigerated storage released particles too, but much less.

The fix is simple and costs almost nothing: put food on a ceramic plate or in a glass dish before microwaving, and let hot food cool before it goes into a plastic container.

Food containers and wraps

• Microwaving in plastic tubs→Glass or ceramic dish, covered with a plate
• Hot leftovers into plastic→Cool first, or store in glass or stainless steel
• Cling film on hot food→A plate, a lid, or beeswax wrap for cold foods
• Plastic containers in the dishwasher→Hand-wash, or replace worn containers with glass

Old, cloudy or scratched plastic containers shed more than new ones. If you keep using plastic, use it only for cold, dry foods.

Tea bags

Strong Some premium "silky" or pyramid tea bags are made of nylon or PET. In a 2019 McGill University study, a single plastic tea bag steeped at 95°C released about 11.6 billion microplastics and 3.1 billion nanoplastics into the cup. A 2024 study from the Universitat Autònoma de Barcelona found that polypropylene, nylon and even cellulose-based bags released millions to billions of particles per milliliter, and showed the particles could be taken up by human intestinal cells in the lab.

Many standard paper tea bags also contain a small amount of polypropylene used to seal them. The safest options are loose-leaf tea in a stainless steel infuser or teapot, or bags specifically labeled plastic-free.

Cutting boards

Emerging A 2023 study at North Dakota State University estimated that one person chopping on a plastic board could produce 14 to 71 million polyethylene particles, or about 79 million polypropylene particles, per year. That is roughly 7 to 50 grams of plastic a year from the board, depending on chopping style and how hard the food is.

Wooden boards released even more particles in the same tests, but those were wood fibers, and the study's authors suggested wood as a way to reduce plastic exposure. Hardwood (maple, walnut, cherry) and bamboo are good choices. Replace plastic boards that are deeply grooved.

Cookware and utensils

• Nonstick pans. PTFE (Teflon-type) coatings can shed particles when scratched or worn. Use wooden or silicone utensils, keep heat moderate, and replace pans with visible damage. Stainless steel, cast iron, carbon steel and enameled cast iron avoid the issue.
• Plastic spatulas and spoons. Nylon utensils used in hot pans can wear and release particles. Choose wood or stainless steel.
• Kettles. Polypropylene kettles shed particles at levels similar to baby bottles when boiling. Choose stainless steel or glass.
• Coffee makers and pods. Hot water passes through plastic parts and pods. A French press, pour-over with paper filter, or stainless steel espresso maker reduces plastic contact.

Food itself

Some foods contain more microplastics before they reach your kitchen:

• Shellfish eaten whole such as mussels, oysters and clams.
• Sea salt. Rock salt and mined salt generally contain fewer particles.
• Ultra-processed foods, which pass through more plastic equipment and packaging.
• Packaged rice. Rinsing rice before cooking removes some particles.

Eating more fresh, minimally packaged food reduces exposure, and is already good advice for other reasons.

Hot drinks on the go

Most paper coffee cups have a thin plastic lining, and plastic lids sit in the steam. Bring a stainless steel or ceramic travel mug, or sit in and ask for a ceramic cup.

Frequently asked questions

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