Abstract: The invention relates to a method and apparatus for treating a perishable material particularly foodstuffs, pharmaceuticals and the like to extend the shelf life thereof including placing a material to be treated in a vessel capable of evacuation, evacuating the vessel and contacting the material with a volatile substance entrained in a carrier gas, the substance being capable of physical and/or chemical alteration of said material. Preferably the volatile substance is an antimocrobial volatile substance, e.g. a natural food acid such as acetic or carbonic acid, and the carrier gas is nitrogen or carbon dioxide.