Abstract: A method of supporting a plastic container exposed to elevated temperatures during product filling and packaging to eliminate heat and internal pressure induced distortion, internal vacuum distortion, or structural failure. Plastic containers usually have a body with exterior configuration and a sealable open mouth. The invention provides a method of hot filling, pasteurising and retort processing of conventional containers during product filling where at least a portion of the container is confined in a support casing having an interior cavity mating the exterior configuration of the container body portion. The product is then introduced into the container, and the container mouth is sealed. A positive pressure is induced within the sealed container while the container is exposed to a product processing temperature. An unsupported PET container exposed to high heat and internal pressure variations would distort or fail.