Abstract: A process is provided for the sterilization of the surface of a packaging material, e.g. a plastic coated board, by contacting such material with a hydrogen peroxide solution, wherein the hydrogen peroxide solution is modified by the addition thereto of a penetration-reducing amount of a penetration-reducing salt. The salt referred to is preferably an alkali metal salt, for instance, a sulphate or halogenide, such as sodium sulphate or sodium chloride. A composition is provided that is useful for carrying the sterilization process into effect, wherein a hydrogen peroxide solution is modified by the addition of a penetration-reducing amount of a penetration-reducing salt.