Microwave popcorn bag, popped state
The bag is typically partially folded when it is placed in a microwave, and inflates as a result of steam pressure from the heated kernels.
The design of a microwave popcorn bag is specifically keyed to avoid popped kernel scorching, an undesirable effect that takes place when popped kernels are heated above 300 F (149 C).
A susceptor, usually a metallised film laminated onto the paper of the bag, absorbs microwaves and concentrates heat at the film interface, thus ensuring a heat distribution focused on the hard-to-heat flavor coating so that the unpopped kernels are evenly coated prior to popping, thereby ensuring even flavor throughout the product.
An early susceptor popcorn bag design was patented by the American company General Mills in 1981 (US Patent #4,267,420).
One danger of the microwave popcorn bag is that after one use the susceptor typically "will lose its ability to safely react to microwave energy. If it is reheated, the changes in the susceptor can cause it to burn."
In 2006, concerns were raised about the levels of perfluorooctanoic acid (PFOA, a chemical related to Teflon) in popcorn bags. The high temperatures used in popping popcorn may facilitate the transfer of the chemical, which is carcinogenic in lab animals, into the popcorn oil. DuPont has agreed to eliminate almost all use of the chemical by 2015.
Additionally, the artificial butter flavoring used in many brands of microwave popcorn has been linked with the obstructive lung disease bronchiolitis obliterans, sometimes referred to as "popcorn lung", in factory workers and others exposed to large amounts of the substance. The chemical diacetyl, the cause of bronchiolitis obliterans, has been removed from some popcorn brands.
Concerned with the above issues people have been making their own popcorn bags from simple paper bags, or popping the popcorn in the microwave in other containers including large glass bowls with heavy, but not airtight glass lids. Both of these home made approaches remove the threat of exposure to artificial flavoring and PFOA, but have a chance of leaving some corn kernels unpopped due to randomness of the microwave radiation distribution in a microwave.
^ "(WO/2001/053167) MICROWAVE FOOD PACKAGE". IP Services > PATENTSCOPE > Patent Search. WIPO. http://www.wipo.int/cgi-pct/guest/getbykey5?KEY=01/53167.010726&ELEMENT_SET=DECL.
^ "Safety Issues Can Zap Unwary Microwave Oven Consumers". Penn State College of Agricultural Sciences. May 23, 2000. http://aginfo.psu.edu/News/may00/microwave.html.
^ "All News Articles". Foodnavigator-usa.com. http://www.foodnavigator-usa.com/news/ng.asp?n=65503-dupont-chemical-pfoa. Retrieved 2009-11-27.
^ "Popcorn May Cause Lung Disease". ABC News. September 6, 2007. http://abcnews.go.com/GMA/OnCall/Story?id=3565670&page=1.
^ "Butter Flavoring Chemical Removed From Popcorn Because of Popcorn Lung" Concern". Injury Board. September 06, 2007. http://lincoln.injuryboard.com/defective-and-dangerous-products/butter-flavoring-chemical-removed-from-popcorn-because-of-popcorn-lung-concern.aspx?googleid=223732.
^ "Microwave Popcorn: Home made, cheap and easy". http://www.instructables.com/id/Microwave-Popcorn:-Home-made,-cheap-and-easy/.
Microwave susceptors in popcorn bags
Alternative popcorn bag patent
Microwave popcorn patent dispute between General Mills and Hunt-Wesson
Dangers of reheating microwave popcorn bags
Categories: Popcorn | Bags | Packaging