[quote]danchubb wrote:
The kid microwaved plastic wrap. This has been discussed before. Just because doing something stupid is dangerous, doesn’t mean the whole microwave is a cancer making machine. spraying oil at a pan while its on a stove could cause the oil to ignite. Stupid, but it doesn’t mean that stove tops are inherently harmful or going to set fire to everything all the time. (I’m tired - couldn’t think of a better analogy).
However, I am open minded - if you DO have more recent studies showing that heating things in ceramic / glass is dangerous / carcinogenic I’d be very interested.
Dan[/quote]
Exactly, those studies aren't a viable argument. Here's what wilkpedia has to say about them also.
Safety and controversy
The dominant view has been that microwaved food is safe to eat. Microwave ovens have become a fairly standard item in most western homes. Microwaving food is fast, energy efficient, and arguably is healthier than traditional means of cooking. Even those who take this view still concede a number of potential safety issues.
[edit] Safety benefits
Commercial microwave ovens all use a timer in their standard operating mode; when the timer runs out, the oven turns itself off.
Microwave ovens heat food without getting hot themselves. Taking a pot off a stove, with the exception of an induction cooktop, leaves a potentially dangerous heating element or trivet that will stay hot for some time. Likewise, when taking a casserole out of a conventional oven, one’s arms are exposed to the very hot walls of the oven. A microwave oven does not pose this problem.
Food and cookware taken out of a microwave oven is rarely much hotter than 100 °C (212 °F). Cookware used in a microwave oven is often much cooler than the food because the microwaves heat the food directly and the cookware is heated by the food. Food and cookware from a conventional oven, on the other hand, are the same temperature as the rest of the oven; a typical cooking temperature is 180 °C (360 °F). That means that conventional stoves and ovens can cause more serious burns.
The lower temperature of cooking (the boiling point of water) is a significant safety benefit compared to baking in the oven or frying, because it eliminates the formation of tars and char, which are carcinogenic. Microwave radiation also penetrates deeper than direct heat, so that the food is heated by its own internal water content. In contrast, direct heat can fry the surface while the inside is still cold. Pre-heating the food in a microwave oven before putting it into the grill or pan reduces the time needed to heat up the food and reduces the formation of carcinogenic char.
[edit] Uneven heating, deliberate and otherwise
In a microwave oven, food may be heated for so short a time that it is cooked unevenly, since heat requires time to diffuse through food, and microwaves only penetrate to a limited depth. Microwave ovens are frequently used for reheating previously cooked food, and bacterial contamination may not be killed if the safe temperature is not reached, resulting in foodborne illness.
Uneven heating in microwaved food is partly due to the uneven distribution of microwave energy inside the oven, and partly due to the different rates of energy absorption in different parts of the food. The first problem is reduced by a stirrer, a type of fan that reflects microwave energy to different parts of the oven as it rotates, or by a turntable or carousel that turns the food; turntables, however, may still leave spots, such as the center of the oven, which receive uneven energy distribution.
The second problem is due to food composition and geometry, and must be addressed by the cook by arranging the food so that it absorbs energy evenly, and periodically testing and shielding any parts of the food that overheat. In some materials with low thermal conductivity, where dielectric constant increases with temperature, microwave heating can cause localized thermal runaway. As an example, uneven heating in frozen foods is a particular problem, since ice absorbs microwave energy to a lesser extent than liquid water, leading to defrosted sections of food warming faster due to more rapid heat deposition there. Due to this phenomenon, microwave ovens set at too-high power levels may even start to cook the edges of the frozen food, while the inside of the food remains frozen. Another case of uneven heating can be observed in baked goods containing berries. In these items, the berries absorb more energy than the drier surrounding bread and also cannot dissipate the heat due to the low thermal conductivity of the bread. The result is frequently the overheating of the berries relative to the rest of the food. The low power levels which mark the “defrost” oven setting are designed to allow time for heat to be conducted from areas which absorb heat more readily to those which heat more slowly.
Microwave heating can be deliberately uneven by design. Some microwavable packages (notably pies) may contain ceramic or aluminum-flake containing materials which are designed to absorb microwaves and heat up which aids in baking or crust preparation. Such ceramic patches affixed to cardboard are positioned next to the food, and are typically smokey blue or gray in color, usually making them easily identifiable. Microwavable cardboard packaging may also contain overhead ceramic patches which function in the same way. The technical term for such a microwave-absorbing patch is a susceptor.
And here’s all about the “cancerous death rays” that storey says will do us all in…
Dangers
A microwaved DVD-R showing the effects of electrical discharge through its metal filmSee also: Microwave-related injury
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Liquids, when heated in a microwave oven in a container with a smooth surface, can superheat; that is, reach temperatures that are a few degrees in temperature above their normal boiling point, without actually boiling. The boiling process can start explosively when the liquid is disturbed, such as when the operator takes hold of the container to remove it from the oven or while adding impurities such as powdered creamer or sugar, and can then result in a violent burst of water and vapor resulting in liquid and steam burns. A common myth states that only distilled water can exhibit this behavior; this is not true.[2]
Closed containers and eggs can explode when heated in a microwave oven due to the pressure build-up of steam. Products that are heated too long can catch fire. Though this is inherent to any form of cooking, the rapid cooking and unattended nature of microwave oven use results in additional hazard. Microwave oven manuals frequently warn of such hazards, but many of them are difficult to foresee. Because the microwave oven’s cavity is enclosed and metal, fires are generally well contained. Simply switching off the oven and allowing the fire to consume available oxygen with the door closed will typically contain damage to the oven itself.
Any metal or conductive object placed into the microwave will act as an antenna to some degree, resulting in an electric current. This causes the object to act as a heating element. This effect varies with the object’s shape and composition.
Any object containing pointed metal can create an electric arc (cause sparks) when microwaved. This includes cutlery, aluminium foil, ceramics decorated with metal, and most anything containing any type of metal. Forks are a good example. This is because the tines of the fork resonate with the microwave radiation and produce high voltage at the tips. This has the effect of exceeding the dielectric breakdown of air, about 3 megavolts per meter (3�?106 V/m). The air forms a conductive plasma, which is visible as a spark. The plasma and the tines may then form a conductive loop, which may be a more effective antenna, resulting in a longer lived spark. Any time dielectric breakdown occurs in air, some ozone and nitrogen oxides are formed, both of which are toxic. Microwaving food containing an individual smooth metal object without pointed ends (for example, a spoon) usually does not produce sparking.
The effect can be seen clearly on a CD or DVD. The electric current heats the metal film, melting the plastic in the disc and leaving a visible pattern of concentric and radial scars. It can also be illustrated by placing a radiometer inside the cooking chamber, creating plasma inside the vacuum chamber.
A microwave oven with a metal shelfSeveral microwave fires have been noted where Chinese takeout boxes with a metal handle are microwaved. Twist ties containing metal wire and paper are also notoriously dangerous.
Another hazard is the resonance of the magnetron tube itself. If the microwave is run without an object to absorb the radiation, a standing wave will form. The energy is reflected back and forth between the tube and the cooking chamber. This may cause the tube to cook itself and burn out. Thus dehydrated food, or food wrapped in metal which does not arc, is problematic without being an obvious fire hazard.
Certain foods if carefully arranged can also produce arcing, such as grapes.[3] A naked flame, being made of conductive plasma, will do the same.
Further information: St. Elmo’s fire
[edit] Controversial hazards
Radiation
Some people are concerned with being exposed to the microwave radiation. According to the United States Food and Drug Administration’s Center for Devices and Radiological Health, a U.S. Federal standard limits microwave leakage from an oven, for the lifetime of the device, to 5 milliwatts per square centimeter when measured 2 inches from the surface of the oven.[4] This is far below the exposure level that is currently considered to be harmful to human health.
The radiation produced by a microwave oven is non-ionizing. As such, it does not have the specific cancer risks associated with ionizing radiation such as X-rays, ultraviolet light, and high-energy particles. Any health problems would result from electric currents induced in the body, most prominently cataract formation. Long-term rodent studies to assess cancer risk have so far failed to clearly identify any carcinogenicity from 2.45 GHz microwave radiation at chronic (large fraction of life span) exposure levels, far larger than humans are likely to encounter even from leaking ovens.[5][6]
To put the radiation hazard into perspective, the formation of carcinogenic char in conventional frying pan or oven needs to be taken into account (see above). The carcinogens in char are toxicated into carcinogens that are radiomimetic (i.e. cause damage similar to ionizing radiation). Microwaving instead of frying or cooking in the oven eliminates this danger.
Believe what you want to. They wouldn't be in every frickin household if they were inherently dangerous to the public health. They are what they are, a complimentary tool for cooking/reheating food safely.