A method for encapsulating a cellulose based substrate with polymeric films involves heating the respective films using a non-electrogmagnetic radiation heating source and providing a pressure differential between an environment defined between the films and an environment external to the films so that conformance of the film to the cellulose based substrate is promoted. The cellulose based substrate is entirely encapsulated by the films and the films are sealed around the peripheral edges of the container as well as edges that are defined adjacent slots and cutouts.