Shelly-Ann Thompson, Freelance Writer
MICROWAVE OVENS are useful for popping a bag of popcorn or baking a cake.
The appliance is appropriate for defrosting, re-heating and cooking. It has become extremely popular among persons with time constraints, to reheat stored or frozen foods like beef burgers in a few minutes. The microwave has revolutionised cooking since its use became widespread in the 1970s.
HISTORY
Cooking food with microwaves was discovered by Percy Spencer while building magnetrons for radar sets at Raytheon. Not surprisingly, the first food to be deliberately cooked in microwaves was popcorn, and the second was an egg (which exploded in the face of one of the experimenters). In North America, popcorn is now one of the most commonly cooked items in microwave ovens, to the exclusion of other home cooking methods such as hot air and oil popping.
In 1946 Raytheon patented the microwave cooking process and in 1947, the company built the first microwave oven, the Radarange. It was almost six feet (1.8m), tall and weighed 750 pounds (340 kg). It was water-cooled and produced 3,000 watts, about three times the amount of radiation produced by microwave ovens today.
By the late 1970s the technology had improved to the point where prices were falling rapidly. Formerly found only in large industrial applications, microwaves increasingly became a standard fixture of most kitchens.
RADIATION
A microwave oven uses microwaves to heat food. Microwaves are radio waves. In the case of the popular and versatile appliance, the commonly used radio wave frequency is roughly 2,500 megahertz (2.5 gigahertz).
There is a school of thought that one must not use the appliance often as this radiation is linked to the cause of cancer.
Microwave ovens produced after 1971 must meet the Food and Drug Administration (FDA) safety requirements for radiation leakage; less than 5mW/cm2 at approximately two inches from the surface of the oven. This is far below the exposure level that is currently considered to be harmful to human health.
SAFETY
If improperly used, microwave ovens can cause damage to the home and to the user. Placement of microwaves is key. "Like other electrical items place where air can flow around it. Like stoves, it's wrong to place your microwave oven next to the wall, it should be away," said culinary expert, Pauline Chin Sue. Safe utensils for a microwave are those labelled for its use, some may be glass and ceramic cookware. To prevent hazards, read microwave manuals.
Do not use equipment or instruments that are made of metal, aluminium, tin, ceramics decorated with metal. These products containing other metals, if used, can cause sparks.
When defrosting food in a micro-wave, remove from store wrapper. Foam trays and plastic wraps may melt and cause chemicals to migrate into the food.
Do not use cold storage containers such as margarine or butter tubs. They can melt 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 or newspapers.
Liquids, when heated in a container with a smooth surface, can overheat, causing burns to the holder.
Products that are heated too long can ignite.
Never put a stuffed bird in a microwave because it may not be properly cooked.
Check food for visual signs that it is done. Juices should run clear and meat should not be pink.
Additional information: http://home.howstuffworks.com/framed.htm?parent=microwave.htm&url=http://ag.arizona.edu/pubs/health/foodsafety/az1081.html; and ; http://en.wikipedia.org/wiki/Microwave_oven
