Microwave Food Safety

Microwaves play an increasingly important role in getting meals on the table, but special care must be taken so that microwaved food is safe to eat. Let’s look at some tips for cooking safely in a microwave oven.

Is it safe to eat microwaved food?  Yes! Microwaves are very short (micro) radio waves that can penetrate food to about 1-1 1/2 inches. The waves carry energy that is absorbed primarily by water molecules.  The absorbed energy causes the water molecules to quickly flip back-and-forth (or vibrate), this heats the water molecules, and eventually converts the water to steam. As steam is conducted through the food, the food heats. Because it is cooked by steam at ~212 °F, food cooked in a microwave doesn’t become brown and crispy as it might when cooked in a oven at 350-425 °F. Food that is microwaved also tends to cool  rapidly.

What do the power settings mean?  At 100% power, radio waves are produced throughout the cooking time; at 50% power the oven produces microwaves 50% of the time. Foods best to cook on high power are basically tender foods and those with a high moisture content such as ground beef, poultry, vegetables and fruits. Eggs, cheese and solid meat can toughen when microwaved on high. They are best cooked on reduced power. Large cuts of meat should be cooked on medium power (50%) for longer periods. This allows heat to reach the center without overcooking outer areas. Microwaves can have different wattages, meaning that the amount of energy in the radio waves can vary slightly.

What containers and wraps are safe to use in the microwave oven? Use cookware that is specially manufactured for use in the microwave oven, check for labels to make sure you are making the right choice. Make sure food is covered to help with even heating and prevent splattering. A clean paper towel (preferably white) works great as a cover.

SAFE TO USE Choose from the following when microwaving food items, following package directions to ensure safety:

  • Any utensil labeled for microwave use.
  • Heatproof glass (such as Pyrex, Anchor Hocking, etc.).
  • Glass-ceramic (such as Corning Ware).
  • Baskets (straw and wood) for quick warm-ups of rolls or bread. Line the basket with napkins to absorb moisture from food and limit heating time to avoid flare-ups.
  • Paper plates, towels, and napkins designed for use with food/meals. For optimal safety use white, unprinted materials.
  • Wax paper, parchment paper, heavy plastic wrap. Follow package directions. Plastic wraps direct consumers not to let plastic wrap touch food; vent plastic to allow a steam escape.
  • Packaging material supplied with a microwave meal or other food item. Some packaging material is designed to collect microwave energy, allowing cooking at higher temperatures; a great example is the  heat-susceptor packaging used in packaging for microwave popcorn or pizza.

NOT SAFE TO USE Not all packaging materials are designed to be used in heating. Avoid using the following:

  • Cold storage containers: margarine tubs, cottage cheese and yogurt cartons, etc. These materials are not approved for cooking and chemicals can migrate into food.
  • Brown paper bags, newspaper, egg cartons or other non-food grade paper materials..
  • Metal containers, e.g. metal pans, metal “twist ties”, aluminum or foil wraps.
  • Foam/styrofoam cups, bowls, plates or trays.
  • Any container that is misshapen from previous use or not designed for microwave use.

Do you know meat and eggs are fully cooked? When cooking meat and egg products, remove the item from the microwave and use a kitchen thermometer to check the temperature before declaring the item ‘done.’ Even if food has reached the right temperature,let it stand for 3 minutes before consuming. This standing allows the heat to each all parts of the food product. Cooking times may vary because ovens vary in power and efficiency.

  • Ground beef  – 160 °F.
  • Steaks, chops or roasts of beef, pork, lamb and veal – 145 °F. For safety and quality, allow meat to rest for at least three minutes before consuming.
  • Poultry – 165 °F.
  • Eggs and casseroles containing eggs – 160 °F.
  • Fish – 145 °F.

Do you need to follow package directions? Most of us use the microwave to help us get a meal on the table, perhaps microwave entrees for lunch or dinner or frozen vegetables as a side dish. It’s important to follow package directions. Puncture the outer wrap, as directed. Check the temperature at the end of the minimum cooking time recommended.  Follow the ‘standing’ time; this is time after heating that may be needed to allow the item to complete cooking. Use the standing time to wash your hands and get ready for your meal!  Stay food-safe, Barb