A method is provided to present a cost - and environmentally - efficient method of pasteurizing and vacuum packing food, comprising the steps of providing a tray (1) with a first separating barrier (11) which divides the tray (1) into a first compartment (4) and a second compartment (5). Both the first compartment (4) and the second compartment (5) each have a flexible bottom, e.g. a first flexible bottom (6) and a second flexible bottom (7). The barrier (11) is formed such that it has a first channel (12) which connects the first compartment (4), which has a valve (16), with the second compartment (5). The contents inside each compartment are pasteurized and cooled, whereby a vacuum is created in the package (15) in such a manner that the flexible bottoms (6,7) are caused to be concave relative the first compartment (4) and the second compartment (5) respectively. The result is a more hygienic and easier to prepare ready-to-eat meal with several compartments for different servings, having only one valve. Moreover, a package (15) is provided to be used in the implementation of said method.