Are Plastic Bowls and Plastic Wraps Microwave Safe?

Do we need to worry about chemicals, particularly plasticizers, migrating from plastic to the hot food in the microwave? Plasticizers, the ingredients in plastic wraps that make them clingy and flexible have been accused of causing cancer and other health problems.

According to research from the School of Public Health at University of California, Berkeley, March 2002, no one knows if these compounds are a danger. Since plastic has not been around for very long, the risk to human health of plasticizers and other chemicals found in plastic remains uncertain. You can avoid any problems by taking the following precautions. It is better to error on the side of caution.

  • Buy wraps that are approved for use with microwaves (most of them will not contain plasticizers). Look for wraps that have manufacturer’s instructions for use in a microwave, as they will be approved.
  • Regardless of the brand you use, be sure that the wrap does not touch food while it is heating in the microwave. Tent it loosely over the food. Don’t seal the edge and leave room for steam to vent. If your wrap does contain plasticizers, they can leach out, but only if they touch the food, and only in small quantities. This has not been shown to be a health risk, but it makes sense to avoid it just in case. Another concern is you don’t want the wrap to melt and ruin the food.
  • You can use waxed or parchment paper, or regular paper towels instead of plastic wrap.
  • Remove the plastic wrap before defrosting meat in the microwave.
  • Use only plastic containers labeled, microwave-safe. This means the plastic is inert (that is, no chemicals will migrate) and they will also be strong enough to withstand the heat. Margarine containers, whipped topping bowls and other thin plastic bowls may warp, and you might get burned when you touch them – a more immediate problem than any migrating chemicals.
  • Restaurant take-out containers and food carriers usually are not intended for the microwave, so transfer your food into a microwaveable container.
  • Don’t reuse segmented trays that frozen dinners often come in. They are meant to be discarded after one use, as the package indicates.
  • Don’t use thin plastic storage bags, brown paper, plastic grocery bags or newspaper.
  • Avoid microwaving food in freezer cartons and on Styrofoam trays.

Choosing microwave safe plastic wrap and containers, and never letting the wrap directly contact food products that are being heated will provide the precautions needed for the safe use of plastic in microwaves.


By Alma Copeland, Home Economist