MadSci Network: Biochemistry |
Well, you know. I was ready to list the dangerous chemicals that would
leach out into your food. So I did a search for a list of those nasty
compounds and found:
at http://www.yahoo.com/
using the argument: +Styrofoam +microwave +cancer http://www.junkscience.com/oct98/
wsjendo.htm and http://rabi.phys.virginia.edu/HTW//microwave_ovens.html
Where a similar question was asked:
"What containers are not safe to use in a microwave? I am particularly
concerned about Styrofoam containers as I use them to make TV dinners for
my family. Is it OK to heat directly in these containers?"
And a better answer than I could cobble up:
"The two critical issues with containers in a microwave are (1) that
they do not absorb or
reflect microwaves and (2) that they tolerate high temperatures.
Concerning the first issue, a
container that absorbs microwaves will become extremely hot and may be
damaged or
destroyed. Most plastics (including Styrofoam) don't absorb microwaves
and are fine.
Glazed water-free ceramics and glasses are usually also fine, as long
as they don't have any
metallic trim. Metal dishes are a poor choice because they reflect
microwaves and lead to
uneven heating. Unglazed ceramics absorb water and will overheat.
Concerning the second issue, many plastics melt or soften below the temperature of boiling water. Polystyrene, the plastic from which Styrofoam is made, has a glass transition temperature of almost exactly 212 Fahrenheit (100 Celsius). That means that it will begin to soften at just about the temperature of boiling water. While pure water will boil without much problem in Styrofoam, water containing dissolved solids such as sugar or salt will boil at a higher temperature and may melt the Styrofoam. You'll know when this happens...it's not really a health issue, just a potential for a messy oven. I've only encountered the problem once myself, when a Polystyrene gravy separator melted in the microwave and let the gravy spill."
Bottom line: there are plastics (including wraps) that SHOULD NOT BE USED in a microwave because heat will cause risky compounds to leach into the food. Those plastics that are safe, will say they are "Microwave Safe" on the container or on the box. Evidently styrofoam is not a plastic that leaches nasty chemicals -- but it isn't labeled "microwave safe" and it will melt.
Try the links in the MadSci Library for more information on Biochemistry.