Microplastic may seem like a health buzzword, but research is accumulating the amount we consume daily, with long-term health risks still unknown.
While the microwave itself is considered safe, placing plastic containers, plastic wrap, silicone and other polymer compounds under its incredibly hot rays can cause more serious problems.
Microwaves and plastic can be a dangerous combination. Here's what experts told me about the risks involved and how to avoid them.
“Microwave safety means that not only will the container not melt or warp, but it also means that it will not release or leach harmful chemicals into our food when heated,” says Lee Li, an assistant professor at the University. University of Nevada, Reno School of Public Healthwhose specialty is environmental health and exposure science.
I spoke with Lee and other materials and health experts about the risks of microwave EMF exposure to various kitchen containers and packaging materials.
That's what they said.
Recommendations for using containers in the microwave oven
Microwave ovens can leach chemicals into food from food storage containers. An expert explains how to avoid this problem altogether.
Before we dive into specific materials and their many parameters regarding microwave suitability, consider the following.
Look for microwave safe labels as a starting point only.
Styrofoam and a microwave are a dangerous combination.
While some materials are generally microwave safe, it's still a good habit to look for any “microwave safe” indications. However, keep in mind that this designation does not tell the whole story.
Similar to: expiration dates of food productsMicrowave safe labeling is not based on a federal certification program. “Manufacturers can use it if their own testing shows it meets microwave safety standards in their opinion. This is a useful guide, but not a guarantee,” says Lee.
In addition, this label does not necessarily indicate any risks to human health.
Throw away any damaged containers.
Damaged food containers can allow chemicals to leach into your food.
Damaged containers can potentially cause chemicals or toxins to leach out of your food. They can also fail due to vibration from the electromagnetic waves that the microwave oven depends on to function.
Regardless of whether the container is labeled microwave safe and regardless of its material, throw it away if it is not in good condition.
“If it has scratches, pitting, cracks or other damage, you can no longer assume it is safe to use in the microwave,” says Kelly Johnson-Arbor, a toxicologist at MedStar Health.
Don't switch from freezer to microwave
Frozen containers, especially plastic ones, should not be placed in the microwave.
“While going from refrigerator to microwave is generally acceptable for most materials, sudden temperature changes should be avoided,” says Lee. Leaving a glass or ceramic container on the countertop for a moment will help reduce the shock when it ends up in the microwave.
“Never go from the freezer directly to the microwave,” says Lee. “Such sudden temperature changes can cause cracking,” which will immediately damage the food inside the container.
Be careful with decorative elements.
Vintage plates, bowls and serving dishes often contain decorations that cannot be used in the microwave.
Even if you're working with microwave-safe material, beware of overly decorated containers and bowls.
Regular patterned ceramic will usually work, but “be careful with decorative coatings or metallic trims, as they may spark or break if overheated,” says Lee.
The best options for a microwave oven: glass and ceramics.
Glass and ceramic containers are generally safe to use in the microwave, Johnson-Arbor says.
“Both act as insulators, meaning they are resistant to heat transfer,” she says, so the vessels themselves don't get hot, but the electromagnetic waves heat the food they contain.
In addition to being resistant to high temperatures, “glass and ceramic containers typically do not contain organic chemical additives,” says Lee.
Glass
Glass containers are safe as long as the rubber or plastic lids do not come into direct contact with food.
Although many glass storage containers have lids with rubber or plastic elements, they are generally fine as long as these elements do not come into contact with food. (But be sure to clean thoroughly to prevent mold from forming on the rubber seals.)
If you're looking for the best option, pans with glass lids and no seals are ideal vessels for cooking and microwaving.
For safe food destruction, glass is your friend.
Ceramics
Ceramic containers are one of the safest options for microwave cooking.
Commercial ceramics are generally microwave safe and should be labeled as such, but be sure to double check those that are more decorative or artisanal.
“The glazes on some ceramics may contain heavy metals, including lead,” says Johnson-Arbor. “When these glazes are heated, the lead can leach out and contaminate the food or liquids in the ceramic container.”
Many ceramic food storage options also come with plastic or rubber lids, but we like the combination of ceramic and glass with silicone lids that can be used in the refrigerator or for shipping, and can be replaced with glass in the microwave.
Ceramic food containers are generally microwave safe.
Can plastic be put in the microwave?
Because the overall impact of microplastics on our health is still unknown, some people choose to avoid using plastic food containers in microwave ovens entirely.
Naturally, this is difficult.
“Many plastic food storage containers contain microwave-safe labels or graphics,” says Johnson-Arbor. “But in recent years, scientists have discovered that tiny plastic particles called microplastics can leach out of food storage containers when heated.”
WITH microplastic Entering the conversation, many brands have claimed to be “BPA free” to put consumers' minds at ease.
“Polycarbonate food containers are made from a group of chemicals called bisphenols,” says Lee. Bisphenol A is commonly called BPA.
“BPA is known to affect hormones and cause some endocrine disruption,” he says. “Even though polycarbonate physically withstands high temperatures to meet manufacturers' 'microwave safe' requirements, microwave heating accelerates the release of BPA, especially when the container is scratched, reused, or contains fatty or acidic foods.”
Read more: Microplastics could end up in your food if you make this simple mistake.
Experts recommend caution and reading the ingredients carefully when using plastic in the microwave.
According to experts, BPA-free containers are slightly better.
“Polypropylene, often called PP plastic or labeled No. 5 plastic, is generally the best option,” says Lee. “It has good heat resistance and generally contains fewer additives than other plastics. However, less does not mean none, and some chemicals such as antioxidants or stabilizers are still used in production.”
Safest position? “Because the overall impact of microplastics on our health is still unknown, some people choose to avoid using plastic food containers in microwaves entirely,” Johnson-Arbor says, which is the safest position to take regardless of whether something is BPA-free.
A plastic film that is usually microwave safe because of its heat resistance. should never come into direct contact with food.
If you don't want to give up the convenience and cost-effectiveness of BPA-free plastic storage containers (and you're willing to take responsible care of them and throw them away if they get scratched), here's a set we've previously recommended.
The paper comes with a latch
Decorative and colored paper plates should not be placed in the microwave.
There are several types of paper you may have on hand in your kitchen, including paper towels, wax paper, parchment paper, butcher paper, and even a variety of paper plates for holiday occasions. Should I put any of these in the microwave?
“For most everyday uses, plain white paper towels or paper plates are generally safe to use in the microwave,” says Lee. A paper towel is a convenient cover for heating food on ceramic plates and helps prevent food from splattering without the need for plastic wrap.
But there's a catch.
“You should avoid microwaving colored or decorated paper plates, brown grocery or take-out bags, or any paper plates with a water- or oil-resistant coating,” he says. “This is because we cannot rule out the possibility that they may smoke, melt or release unwanted chemicals when heated.”
The same applies to wax paper, which can melt or break down in high temperatures or when in contact with certain types of foods. If a paper product has a shiny or smooth side, it is generally best to avoid it.
Metals are never suitable for microwave use
Keep any metal, including aluminum foil, away from the microwave oven.
When it comes to microwave cooking, metals are dangerous not because of health issues or heat resistance. Stainless steel and cast iron are great materials for cooking on the stovetop, but they should not be placed in the microwave due to the way microwaves operate. Microwaving them is counterproductive and dangerous.
“Metal reflects electromagnetic waves,” Johnson-Arbor explains, which prevents them from heating up your food. “This may cause heat to transfer to other surfaces in the microwave, which may result in overheating or fire.”
