More than 90 percent of households in the U.S. are equipped with a microwave oven, which converts electricity into an electromagnetic field to cook your food. Seasoned chefs know that the microwave ovens can save you time and be helpful in preparing meals, but microwaves cook food differently than traditional cooking methods, posing some special considerations. Microwave ovens are fast and efficient, but they also have some disadvantages.
Microwave ovens work by moving food particles against each other on a molecular level, using the food's water molecules. Foods with a high moisture content tend to cook more successfully in microwaves for this reason, leaving lower water-content foods more prone to drying out during cooking. Meat, eggs and cheese have a tendency to toughen in the microwave, unless cooked on lower power settings. Additionally, large items will overcook on the outside before cooking through to the middle unless power settings are carefully reduced.
During cooking, the air inside the microwave remains at room temperature, which is different than traditional cooking methods. Conventional ovens, for example, cook food with hot air. This means cooking in an oven causes food surfaces to brown and crisp, while microwave cooking does not brown food surfaces. This can be a disadvantage for both texture and presentation, depending on the food.
The physical and electrical properties of each food determines how quickly and evenly it will cook in the microwave, but microwaves generally penetrate to a depth of 1 to 1.5 inches. Food thicker than this cooks on the outside, then inside areas cook by conduction, creating less even cooking than traditional ovens. Uneven cooking can produce both hot spots as well as undercooked areas, which can, in turn, cause burns or fail to destroy bacteria or pathogens leading to foodborne illnesses. The U.S. Department of Agriculture suggests measuring the foods' temperatures in multiple spots to ensure the food is completely cooked throughout.
According to clinical nutritionist and psychologist George J. Georgiou, Ph.D., microwave cooking can be hazardous to your health in a number of ways, including creating cancer-causing agents, releasing radioactivity into the environment and causing a degeneration of the immune system. Little evidence is available to support Georgiou's claims, and the USDA's Food Safety and Inspection Service adamantly proclaims that food cooked in microwave ovens is safe to eat. Additionally, research published by "The Journal of Food Science" in September 1980 indicated microwave cooking does not adversely affect the foods' chemical properties. To avoid the release of chemicals during microwave cooking, use glass or glass-ceramics, and avoid any packaging that can melt during cooking.