Abstract: A packaging container for use in connection with microwave cooking of foodstuffs is provided. The container can be opened up so as to define an extended base area, allowing foodstuffs comprising individual items to be spread out during cooking. The extension is achieved by utilization of container portions not originally part of the base. The extended base area preferably is covered with microwave susceptible material.

Abstract: A microwaveable package containing foodstuff is for direct placement with or without opening same, in a microwave oven so that the foodstuff can be microwave cooked. The foodstuff rests on a sheet of microwave receptor material and the package is designed so that there is an air space between the receptor material and the oven support table to prevent the table from acting as a heat sink to drain away heat generated by the receptor material during cooking.

Abstract: The invention provides that receptor material sheet is so formed or treated as to vary the microwave heating characteristics thereof. In one arrangement, the microwave heating characteristic is varied by corrugating the receptor material, while in another case the sheet material is embossed or treated so as to break up the receptor layer. In preferred arrangements the above two features are embodied in the same material, and according to a further preferred feature the receptor materials are embodied in packages for foodstuffs to be microwave cooked.

Abstract: The invention provides that receptor films for use in microwave ovens for the browning and crisping of foodstuff are created by forming a composition which is liquid in nature and contains interactive particles. The composition is laid down in order to form a film which is then dried in order to fix the interactive particles in distributed form so that they will behave as an interactive layer when subjected to microwave radiation. It is suggested that the interactive particle layer should be covered by a protective layer such as heat curable varnish in order to isolate the particles from the foodstuff which will be adjacent thereto to be crisped and browned thereby. The composition comprises a cross linking and heat resistant resin acting as a binder so that when the composition is applied on a receiving surface, it is cured for example by subjecting it to heat to fix the particles in distributed condition.

Abstract: The invention provides that a microwavable tray is provided with a skirt which covers those areas of the tray subjected to heat radiation when the tray is placed under a grill for the grilling of the tray products, said skirt being of a heat reflective material.