Food Safety, Preparation and Storage Tips
Cooperative Extension, College of Agriculture & Life Sciences, the University of Arizona

Microwave Cooking

Microwave ovens are safe to use for defrosting, reheating, and cooking. However "cold spots" can occur in microwaved foods because of the irregular way the microwaves enter the oven and are absorbed by the food.

If food does not cook evenly, bacteria may survive and cause food-borne illness. Simple techniques to minimize the cold spots include stirring and rotating the food once or twice during microwaving, arranging foods uniformly in a covered dish, and turning large foods upside down during cooking.

When defrosting food in the microwave, remove food from store wrap first. Foam trays and plastic wraps may melt and cause chemicals to migrate into the food.

Always cook meat and poultry immediately after micro thawing. Some areas of the frozen food may begin to cook during the defrosting time. Holding partially cooked food is not recommended because any bacteria present wouldn’t have been destroyed. Remember to take food that has been defrosting out of the microwave.

Never stuff a bird that will be cooked in a microwave because it may not cook thoroughly.

Utensils that are safe for microwave use include glass, glass ceramic cookware, and those labeled for microwave use. Don’t use cold storage containers such as margarine tubs since they can melt from hot food and can cause chemical migration.

Wax paper, oven cooking bags, parchment paper and white microwave paper towels are safe for microwave use.

Never use brown grocery bags, newspaper, metal, or foil in the microwave.

Foods being reheated in the microwave should be steaming and hot to the touch, or at least 165° F. Cover foods and stir them from the outside in, to encourage safe even heating.

Due to the possibility of uneven heating, microwaving baby food and formula is not recommended because hot spots could burn the baby’s mouth.

To ensure a more even distribution of heat when cooking large pieces of meat in the microwave, first, remove the bone, cook on medium power (50%) for longer periods of time, and rotate once or twice during cooking .

If meat is only partially cooked in the microwave, remember to transfer it to another heat source such as a barbecue grill immediately to complete the cooking process.

The use of a meat thermometer or oven’s temperature probe is recommended to verify the food has reached a safe temperature. Check in several places to be sure red meat is 160° F; poultry, 180° F. Check for visual signs of doneness. Juices should run clear and meat should not be pink.

Follow recommended standing times given so cooking is completed.


Material written by Mary Abgrall and Scottie Misner, May 1998.
Part of Food Safety Tips, College of Agriculture, The University of Arizona
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