Is It Bad to Use Plastic in Microwave Cooking?

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You likely use plastic containers and plastic wrap, which are staples in most kitchens. Plastic bowls and wraps are often used to heat leftovers or quick after-school snacks for kids. Some of these plastics are safe for microwave use, while others are not meant to withstand the high heat of the microwave. A few pointers will make it easy for you to remember which plastics you can use in the microwave and which you should steer away from to keep your family healthy.

Plastic Containers

Many popular plastic containers are specially designed for microwave use. Look for a "microwave-safe" label, usually on the underside of the container. This "microwave-safe" label indicates that the FDA has tested the container in the microwave and that the package will not melt under the high heat. Other packages contain a symbol such as a square with wavy lines or instructions for microwaving food correctly. These labels also indicate that a plastic container is safe for the microwave.

Do not use take-out containers or the plastic containers from margarine or whipped topping.

Plastic Wrap

Most plastic wrap is safe for use in the microwave when used in the right way. Like plastic containers, plastic wrap is usually has a "microwave-safe" label if it has been tested in the microwave. Plastic wrap does not heat when exposed to the energy of the microwave, but it can heat up when it comes into contact with the hot food while cooking.

When using plastic wrap, place the wrap loosely over the dish you are microwaving. The plastic wrap helps retain moisture, prevent splatter and allows food to cook more evenly. Since it is the food that gets heated, not the plastic wrap, make sure to leave an inch between the plastic wrap and the food so that the two do not touch in the microwave.

Other Instructions

When using plastic in the microwave, make sure to follow any other written instructions. Some prepackaged meals are served in plastic containers that are safe for one-time microwave use. These containers usually state that you should cut a hole or slit in the plastic on top or that you should lift one of the corners to allow air to escape.


The Plastics Info website notes that when cooking food in plastic containers, cut the food up into small, uniform pieces, as you would with any other cooking process. This will allow the food to heat evenly and reduce the heating time. Reduced heating time will make it less likely for the plastic to melt or warp. Add sauces, such as ranch dressing or spaghetti sauce, in the last few seconds of cooking, as the liquids typically heat faster than a food such as meat. Burning the liquids could result in burning a hole through the plastic