SELECTING A MICROWAVE OVEN

Microwave ovens allow you to heat food in seconds, but consumers should take their time researching what type of oven to buy, says Mark, a food scientist at Penn.

--Power. Unlike the fictional Tim the Toolman on TV's "Home Improvement," consumers should not blindly choose a model with more power. Mark says most cooks should purchase ovens that are about 600 to 800 watts in power, rather than larger units of 900 to 1,100 watts. "In high-power ovens, time of heating plays a more crucial role in determining doneness," he says. "A few extra seconds could mean disaster -- the product could be splattered over the inside of the oven.

"Many frozen dinners and other recipes are formulated for ovens that are about 700 to 800 watts, because most consumers own ovens in that range," he adds. "Purchase a more powerful oven if you cook larger meals such as a roast or whole chicken. Make sure the oven cavity is large enough to hold larger food items."

--Convection Combination? A combination microwave and convection oven is effective at cooking food such as pizzas and rolls that do not cook properly using just microwave power. These ovens even brown the food products that a typical microwave oven cannot. Because microwaves heat from the inside out, Mark says combination convection ovens can help dishes cook more evenly and dissipate the moisture released during microwave cooking.

"Combination ovens are more expensive, but they do a good job," he says. "They are particularly effective in heating products that need to come out crispy."

There are combination microwave/broiler ovens in use in Europe, and in selected markets in the United States, for cooking meats and other items. The ovens, which use a quartz heating element, retail for about $400. "In Europe, the kitchens are much smaller, so people require smaller appliances that are more functional," he explains.

--How Many Buttons? Mark says microwave ovens feature many functions and buttons that may not fit the cooking style of a consumer. "There are ovens with 'popcorn buttons' that shut off when the oven reaches a certain humidity level," he explains. "But it may be better to buy a medium-sized oven and keep the most successful popping time in your memory." The magnetron that generates microwaves loses power as it ages, Mark says. Although the slippage is slight, it can affect the performance of pre-timed buttons on the oven's keypad.

--Carousel. Mark suggests consumers buy an oven with a rotating carousel. He explains that food items absorb microwaves more evenly if they rotate. "It's also easier to clean, and the glass platform is raised slightly, allowing microwaves to heat underneath the item."

--Dual Wave Ovens. Mark says appliances that have two ports from which microwaves are introduced into the oven generally heat more evenly than those using a single wave source. He says dual-wave ovens often are slightly more expensive.

--Interior. Mark says consumers should look for ovens with rounded corners and enamel surfaces, to make cleaning easier. "Make sure the air vents are at the top of the oven cavity," he says. "Otherwise they can get clogged or dirty from food particles."

--Outside Vents. Make sure you know where the heat and moisture is vented outside the oven. Mark says microwave ovens must be placed away from walls and other surfaces in order to have room for air circulation. "Microwave ovens put out a lot of moisture," he says. "Excess moisture can cause wallpaper to fail or ruin nearby cabinets or valuable furniture."

--Door Locks. Mark suggests purchasing an oven with a push-button lock. Steam produced within the food can raise pressure inside the oven and cause other types of locks to pop open, creating a hazard.

--Adequate Light. It's important for the cook to see the product clearly as it is cooking. Mark says the lamp should permit you to see inside, and the door glass should not be tinted too darkly.

--Location. Children should be taken into account when buying a microwave oven. "Make sure they can use it," Mark says. "More importantly, it should be placed where young children cannot get to it, but not so high that adults and older children are in danger when removing food items from the oven."