Microwaving food in plastic: what the FDA says about containers, melamine plates and microplastics

The Food and Drug Administration gives two kinds of answer. On containers, it says plastic tableware that “does not specify that it’s microwave-safe should not be used to heat foods and drinks,” and that food should not be heated on melamine dinnerware in a microwave at all. On microplastics, it says “current scientific evidence does not demonstrate that levels of microplastics or nanoplastics detected in foods pose a risk to human health,” and that there is not sufficient evidence that particles from plastic food packaging migrate into foods and beverages. A 2023 laboratory study found large numbers of particles released when some plastic containers were microwaved, and the FDA says more research is needed before it can assess the health effects.

How plastics that touch food are regulated

The FDA calls packaging, processing equipment, food preparation surfaces and cookware “food contact substances.” By law, materials used in products that come into contact with food must be authorized by the FDA before they are marketed for that use, usually through a food contact notification. In that review, the agency says, it analyzes testing data on how much of a substance migrates into food “based on its intended condition of use,” along with toxicological data, to make sure the resulting exposure is safe. The FDA keeps a public inventory of the uses it has authorized this way.

The FDA pages we read on November 14, 2026, do not define a “microwave-safe” label. In our reading, they tie safety to the conditions of use a material was reviewed for, and the agency's advice on heating turns on whether a product specifies that it is microwave-safe.

Melamine dinnerware

Melamine plates and cups are made from melamine-formaldehyde resin, and a small amount of melamine left over from the reaction can migrate very slowly into food, according to the FDA's questions and answers on melamine tableware, last updated in December 2017. In tests the FDA cites, melamine migrated only into acidic foods, from three of 19 plates and cups, under exaggerated conditions: food held in them at 160°F for two hours. Adjusted for actual use, such as cold orange juice held for about 15 minutes, migration would be under 10 parts per billion, which the FDA says is 250 times lower than the 2,500 parts per billion it has concluded is acceptable in foods other than infant formula.

Heat changes that. When highly acidic foods are heated to 160°F or more, the amount of melamine that migrates can increase, the FDA says, so foods and drinks “should not be heated on melamine-based dinnerware in microwave ovens.” It says only ceramic or other cookware that specifies it is microwave-safe should be used, and the food can then be served on melamine.

BPA

Bisphenol A (BPA) has been used in certain food contact materials since the FDA first approved it in the early 1960s. In fall 2014, FDA experts completed a four-year review of more than 300 studies and found nothing that prompted a revision of the agency's safety assessment of BPA in food packaging. The FDA's BPA page, last updated in April 2023, says the agency is currently reviewing a BPA petition it received and filed under its food additive petition rules, and will publish its response in the Federal Register. That petition, submitted by the Environmental Defense Fund and other groups and scientists and filed by the FDA on May 2, 2022, proposes that the FDA remove or restrict authorizations for the use of BPA, according to the agency's Federal Register notice of July 11, 2022. When we searched the Federal Register on November 14, 2026, it listed no FDA response.

What the FDA says about microplastics

Microplastics are typically considered pieces of plastic under five millimeters in at least one dimension, and nanoplastics under one micron, against about 70 microns for the diameter of a human hair; the FDA notes there are no standard definitions. Studies have reported microplastics in salt, seafood, sugar, beer, bottled water, honey, milk and tea, and in human samples including urine, stool, blood and organs. The agency says environmental contamination where food is grown or raised is the likely main source of any particles in food, that many studies used methods of “variable, questionable, and/or limited accuracy and specificity,” and that not enough is known about health effects.

The FDA says it continues to monitor the research and can take regulatory action if scientific evidence shows that microplastics or nanoplastics in food, including packaged food and beverages, harm human health. No FDA regulation authorizes them as food ingredients, and the EPA has set no regulatory levels for them in tap water, the FDA's page notes.

What a 2023 microwave study found

Researchers at the University of Nebraska-Lincoln, writing in Environmental Science & Technology in June 2023, bought two brands of polypropylene baby food containers and a reusable food pouch from a U.S. chain store. They filled the containers with water or 3% acetic acid, which the researchers say FDA guidelines recommend as simulants for watery and acidic foods, and heated them in a microwave at full power, 1,000 watts, for three minutes. The pouch was not microwaved because it was not suitable for microwave use.

The researchers also exposed human embryonic kidney cells to particles extracted from a container and reported that about 77% of the cells died at the highest concentration tested after 48 and 72 hours. The work used food simulants, laboratory conditions and cells in a dish; in our reading, it does not show effects in people, and the FDA's position, quoted above, is that current evidence does not demonstrate a risk at the levels found in foods.

Where to check a product

The FDA's advice turns on what a product itself specifies about microwave use, and the agency's public inventory of food contact notifications lists the authorized uses of the substances it has reviewed. Our guides to microwave oven safety and to state PFAS bans on cookware cover related questions.