FOOD SAFETY SMART MICROWAVING

Faster than a conventional oven, more powerful than a toaster, able to cook meals in less than an hour, microwave ovens can be found in 82% of American households. Microwave cooking has been around for more than forty years. In 1945, Dr. Percy Spenser patented a microwave that he built from a milk can. The first ovens for home use were first marketed by Raytheon in 1955.

Microwaves are a form of magnetic and electrical energy moving through space. They are absorbed by foods but reflected by metal. The microwaves, which are produced by a magnetron element, bounce around inside the metal oven until they are absorbed by food, and produce heat.

Although the microwaves produce heat directly in the food, it is uneven. "Cold spots" can occur when the microwaves bounce around the oven irregularly, or the microwaves heat the fats, sugars and liquids in foods quicker than other elements in the food.

The microwaves do not cook food from the inside out, especially thick foods such as roasts. They generally cook about an inch of the outer layers. The heat is then slowly conducted inward, cooking along the way. To promote uniform cooking, recipes for the microwave usually include directions for turning the food midway through cooking and/or cover and let stand after cooking.

For Safe Microwaving

• Food that has been improperly stored or otherwise mishandled cannot be made safe to eat by reheating in the microwave.
• Be familiar with the information in the owner's manual.
• Cook food immediately after defrosting in the microwave.
• Debone large pieces of meat, poultry or fish before cooking, Bone can shield the meat around it from thorough cooking.
• Cook large pieces of meat or poultry at 50% power for longer periods of time. Oven cooking bags aid in even cooking and tenderness. Trapped steam kills bacteria in the centers of thick roasts where microwaves can't penetrate.
• Do not cook whole, stuffed poultry in the microwave. Cook bird and stuffing separately.
• Use a meat thermometer or temperature probe to check for doneness. Check in several places, avoiding fat and bone. The internal temperature should reach 165°F for red meat, 180°F for poultry. Fish should flake.
• Arrange smaller items or mixed foods uniformly in a covered dish. Add a bit of liquid. The steam formed inside the dish helps kill any bacteria or other pathogens and ensures even heating.
• Move food around inside a dish several times during cooking. Stir soups and stews. Turn the dish several times during cooking.
• Mixed foods, casseroles, soups, stews, and re-heated carry-out and leftover foods should all be heated to at least 165°F. Turn the dish and stir contents several times during the heating process.
• For all foods, observe the standing time given in the recipe, usually about one-third of the cooking time. Food completes cooking during the standing time.
• Don't use the microwave for deep-frying, canning, or heating baby bottles. These applications don't allow adequate temperature control for safe results.
• Don't dry or disinfect clothing or other articles in the microwave because of the risk of fire.
• Always cover your cookware with glass or plastic that does not touch the food. It traps steam and helps to evenly distribute the heat.
• Glass cookware, glass ceramic cookware, and waxed paper are safe for microwave cooking. Plastic wrap may be used to cover containers should not touch the food. Before using other types of containers, check to be sure that they are approved for use in the microwave oven. Non approved materials may melt, burn, or contain chemicals that can migrate into the food during cooking.
• Always use potholders when removing items form the microwave. While microwaving may not cause the dish to get hot, the food inside does and might burn.

Revised 6/00
University of Rhode Island
Cooperative Extension Food Safety Education