Chow Line: Microwave ovens safe if used properly

April 27, 2012

A friend forwarded an email message that showed how using water heated in the microwave (and then allowed to cool) can kill houseplants. Is using the microwave to heat food safe?

First, let me ease any anxiety over houseplants. I’m not sure who would heat water in the microwave before using it to water plants, but the email message you saw, which appears to have been making the rounds since 2006, is either a hoax or just a badly designed experiment. In fact, it’s listed on Snopes.com, a well-respected urban-legend/myth-busting website, as “False.” For details, see http://www.snopes.com/science/microwave/plants.asp.

But your inquiry brings up the larger question of the safety of cooking food in the microwave oven. Well, you don’t need to worry. It’s perfectly safe, as long as you do it properly. Using the microwave oven is fast and convenient, but, because of uneven heating in some foods, it can create a food safety risk.

Recently, the nonprofit Partnership for Food Safety Education -- the organization behind the “Fight Bac!” campaign -- produced some “Cook It Safe” materials with guidelines on safely using the microwave oven. Its tips include:

  • Read and Follow Package Cooling Instructions. Ready-to-heat meals are not always ready to eat after a few minutes in the microwave oven. The heating instructions are developed for a reason. Not following them might result in a nasty case of foodborne illness.
  • Know When to Use a Microwave or Conventional Oven. Meals designed to be heated in the microwave are so common that it could be surprising to find some that need to be slowly heated in a conventional oven. Those could be foods that contain raw ingredients or are shaped irregularly and have trouble heating evenly in a microwave, creating cold spots where bacteria could thrive.
  • Know Your Microwave Wattage Before Microwaving Food. Many foods have cooking instructions that vary depending on the oven’s wattage. Take a look on the microwave oven’s door or on the serial number plate on the back, or contact the manufacturer to find out the wattage. 
  • Always Use a Food Thermometer to Ensure a Safe Internal Temperature. This is always a good idea, no matter how your food is cooked. Test food in several places to make sure it’s cooked thoroughly.

For more tips or to view the videos, see http://fightbac.org/cookitsafe

Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or filipic.3@osu.edu.

Editor: This column was reviewed by Linnette Goard, assistant professor and field specialist in Food Safety, Selection and Management, in Family and Consumer Sciences for Ohio State University Extension.

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Author(s): 
Martha Filipic
Source(s): 
Linnette Goard