Microwave Do’s and Don’ts

A Healthier Michigan

| 4 min read

Craving a bag of popcorn or in a pinch to reheat last night’s leftovers? Microwaves are probably your go-to appliance in these situations but are there times when you shouldn’t use the convenient appliance? While they may seem magical by rapidly cooking food and having meals ready in minutes, you should be cautious of cooking certain foods in microwaves.

The science behind microwaving

Microwaves work in the same way radio waves supply music to your car or how telephones allow you to communicate with people around the world. Small energy waves target the water molecules in food causing them to constantly flip and create friction, which heats the food.
While some people think microwaves cause cancer, the truth is that they are as safe as talking on the telephone. The energy waves in microwaves emit non-iodizing radiation, which is the same type of radiation as a telephone. The metal covering on microwave doors even helps to keep the small amount of radiation central to the appliance, which is absent in phones. Radiation strength decreases with distance, so it is recommended to stay at least a foot back and refrain from pressing your head against the microwave, however
Microwaves can unevenly heat food since the cook time and temperature is lower. This can lead to an increased risk for bacteria and food-borne illnesses. Always be sure to read the cooking instructions when preparing foods that could carry harmful bacteria.
Microwaves may seem like the go-to appliance to quickly cook food, however you should use caution when microwaving some items. Microwaves quickly cook food, which causes a majority of the nutrients to be destroyed such as phytochemicals, antioxidants, vitamins and minerals. Vitamins that are soluble in water, such as C and B, are more susceptible to microwaves than fat-soluble vitamins like A, D, E and K. For example, it would take 45 minutes for an oven to destroy cancer-fighting components in garlic, while a microwave would take only one minute.

Microwave do’s

  • Microwaves should be cleaned at least once a week with baking soda and vinegar to reduce the risk of bacteria build-up.
  • Shift your food halfway through the cook time and stir occasionally if your microwave doesn’t have an automatic turn plate.
  • Use a thermometer to check the temperature on bacteria-prone food that is cooked in a microwave to ensure it’s reached 165 degrees Fahrenheit.
  • Use glass or ceramic plates and bowls to heat food in the microwave.
  • Cover food to prevent splatters.
  • Be aware of cook times – each food item is different and requires a different length of time to cook it.
  • Vitamin C or B-dense veggies that must be cooked in the microwave should be steamed by leaving them in the package.

Microwave don’ts

  • Take-out containers with metal should never be microwaved because the metal can cause fires in the microwave. Be sure to move your leftover food to a microwave-safe container unless the packaging specifically states it can be microwaved. Stainless steel travel mugs, aluminum foil and metal plates fall into this category, too.
  • Lunch bags can release toxic fumes in the microwave or even cause fires so refrain from microwaving.
  • Yogurt containers or Styrofoam are made for a one time use and aren’t made to withstand microwave heat.
  • Hard-boiled eggs shouldn’t be microwaved unless you like to clean up messes. The rapid heat creates steam in an egg, which can cause it to crack before it reaches the hard-boiled consistency.
  • Fresh fruits and vegetables aren’t made to withstand microwave heat and many will explode, creating a huge mess. Nutrients can also be destroyed in the microwave, especially water-soluble vitamin-dense fruits and veggies such as guavas, yellow bell peppers, thyme, parsley, mustard spinach, kale, kiwis, broccoli, Brussel sprouts, lemons, strawberries and oranges.
  • Microwave heat can cause hot peppers to catch on fire. The chemicals that make peppers hot will also be released during the process, which will sting your eyes and throat.
  • Plastic containers can cause BPA or phthalates (type of chemical plasticizers) to leak into the food if placed in the microwave.
  • Putting nothing in the microwave and turning it on can cause the appliance to blow up as there will be nothing to absorb the waves.
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Photo credit: Getty Images

A Healthier Michigan is sponsored by Blue Cross Blue Shield of Michigan, a nonprofit, independent licensee of the Blue Cross Blue Shield Association.
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