Abstract: A heat-in package with doneness indicator for heating applications, such as microwave heating of foods or sterilization applications. The doneness indicator comprises indicia printed with thermochromatic ink on the heat-in packaging. The doneness indicator can be sealed from front to back on the heat-in packaging in such a way that the heat transfer to the sealed area is controlled so that the contents contained within the heat-in packaging has adequate time to heat before a color change or other visual transformation is observed in the doneness indicator. Furthermore, the sealed area containing the thermochromatic ink is not in direct contact with the contents within the packaging. The ink changes due to heat conduction through the film. A venting system can further be incorporated to prevent excessive pressure build-up within the packaging.

Abstract: A flexible pouch for cooking a food item using microwave energy. The pouch includes a base configured to retain hot gases above atmospheric pressure within the pouch to heat and cook the food item when the package is exposed to microwave energy. The pouch also includes a cover comprising a sealant layer and a score layer. The score layer includes a weak portion which ruptures and vents the pouch at a predictable location when pressure within the pouch due to the hot gasses exceeds a predetermined pressure.

Abstract: A flexible pouch for cooking a food item using microwave energy. The pouch includes a base configured to retain hot gases above atmospheric pressure within the pouch to heat and cook the food item when the package is exposed to microwave energy. The pouch also includes a cover comprising a sealant layer and a score layer. The score layer includes a weak portion which ruptures and vents the pouch at a predictable location when pressure within the pouch due to the hot gasses exceeds a predetermined pressure.