Microwave popcorn

In addition to the dried corn, the bags typically contain cooking oil with sufficient saturated fat to solidify at room temperature, one or more seasonings (often salt), and natural or artificial flavorings or both.

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.

Microwave popcorn bags are designed to avoid popped-kernel scorching, an undesirable effect that takes place when popped kernels are heated above 300 °F (150 °C).

[3] The first use of popping corn kernals was when Raytheon engineer Percy Spencer further tested his observation of a nut candy bar melting in his pocket while working with radar tubes during WWII.

Some microwave ovens have a specific mode designed for cooking popcorn, which either uses factory-calibrated time and power level settings, or which uses humidity or sound sensors to detect when popping has finished.

In addition, the use of perfluoroalkyl ethyl-containing food-contact substances are no longer allowed by the U.S Food and Drug Administration (FDA) regulations in January 2016.