Safely Microwaving with Plastic Containers

Most of us are familiar with the idea that plastics can cause chemicals to leak into microwaved food if the plastics are in containers or wrap.

But there’s no single substance called “plastic.” That term covers many materials made from an array of organic and inorganic compounds, the Health Letter says. Substances are often added to plastic to help shape or stabilize it. Two of these “plasticizers” are bisphenol-A (BPA), added to make clear, hard plastic, and phthalates, added to make plastic soft and flexible

The Harvard experts say that both these plasticizers are believed to be “endocrine disrupters,” meaning that they harmfully mimic human hormones.

When food is wrapped in plastic or placed in a plastic container and microwaved, BPA and phthalates may leak into the food, especially if the food is fatty.

The FDA regulates plastic containers and materials that come into contact with food, the Harvard Health Letter says, and reviews test results before approving a container for use in a microwave. Containers that pass the test are the only ones that can display a “microwave-safe” icon or words. (Although Styrofoam is commonly believed to be unsafe, it can be used as long as it has this label).

Here are some tips from the Harvard experts about microwaving food in plastic:

If you worry about the dangers of plastic containers, use microwave-safe glass or ceramic containers.

Don’t let plastic wrap touch food during microwaving; otherwise; it may melt. Instead, use wax paper, paper towels or kitchen parchment paper.

What containers are not safe for microwaving? Most takeout containers, water bottles and tubs of the kind used to hold margarine, yogurt or whipped topping.

Avoid using old or cracked containers or containers that have been microwaved many times. They may leach out more plasticizers into the food

Never microwave plastic storage bags or plastic bags from the supermarket.

For more information on food safety and nutrition, click here to order Healthy Eating from Harvard Health Publications.