A system and method for decontamination of product is described. An object to be treated, which may be a food product or a medical device, is placed in a substantially closed dielectric container with a working gas. The container is placed in an apparatus capable of producing a controlled electrical discharge so as to create reactive ion species within the package. The object to be treated may be exposed either the immediate products of the electrical discharge or the long lasting reactive ion species, or both, so as to treat the object to reduce or eliminate specific contaminants, which may be biological pathogens or the cause of product spoilage, or inorganic contaminants. The reactive ion species may result from an atmospheric non-equilibrium plasma (ANEP) formed by the apparatus and the treatment may be performed without significantly increasing the bulk temperature of the object being treated.