Controlled heating of foodstuffs by microwave energy

A multiple layer article of manufacture, adapted to be formed into a packaging structure in which a foodstuff may be heated by microwave energy to an edible condition, comprising:

• a layer of flexible electroconductive material supported on a substrate layer,
• said layer of flexible electroconductive material having a thickness which is normally substantially opaque to microwave radiation and having a plurality of elongate apertures extending wholly through the thickness of said electroconductive material layer and effective to generate thermal energy in said plurality of apertures when said article is exposed to microwave energy and the foodstuff is in contact with or proximate to said plurality of apertures,
• said plurality of apertures being sized and arranged in said layer of flexible electroconductive material to generate sufficient thermal energy to effect a desired surface browning of the foodstuff while permitting sufficient microwave energy to penetrate said layer of flexible electroconductive material through said plurality of apertures into the foodstuff to effect a desired degree of heating of the foodstuff, whereby the foodstuff may be provided in an edible condition, and
• said substrate layer being formed of microwave energy transparent material and being in adhered structural supporting relationship with said flexible layer of electroconductive material so that a packaging structure may be formed from said article in which said foodstuff may be positioned.