A comesitble container has a wall or envelope made from a plastics multilayer structure in which one layer is an oxygen barrier to guard against ingress of oxygen. The structure also comprises an activatable oxygenphilic substance, e.g. to deliquescent sulphite, between the barrier layer and the container contents or comestible, this substance being protected against moisture reaching it at least from the contents by a polymeric layer impermeable to water at normal storage temperatures but permeable thereto during filling the container or retorting it for sterilizing its contents. Wetting of the substance changes it from a passive state to the oxygenphilic state whereupon it commences fixing the oxygen in a chemically-bound state.; A similar activatable structure can serve as an oxygen-scavenging insert for a container, and comestibles can be protected by sealing them in their containers followed by activating the substance to its oxygenphilic state.