The present invention relates to a food package for cooking, storing and heating of ready-to-eat food. The food package comprises a food container (65), a plastic film (26) for sealing the food package from ambient air and being provided with an opening (16), said food package further comprising an openable and resealable valve membrane (52, 62) of a thermoelastic material covering said opening, wherein an adhesion between the valve membrane (52, 62) and the surface it is applied on is lower in a first area (160) than in a second area, wherein said first area (160) extends in a direction at least between said opening (16) of said plastic film and an edge of said valve membrane (52, 62), such that a canal (60) may be created between said opening (16) and a valve membrane periphery during cooking and/or heating of said ready-to-eat food, wherein the valve membrane has a production machine direction (8) of the thermoelastic material which has a relationship to said direction of said first area such that an angle therebetween is within an interval of 60° to 90°.