High concentration, that is, strong antimicrobial treatment materials such as high concentration aqueous ammonia solutions or even liquid ammonia may be applied to a foodstuff (202) without deleterious effects by controlling the temperature of the foodstuff at or immediately after the time of contact with the antimicrobial treatment material. In particular, ice crystals are maintained at or just below the surface of the foodstuff at or immediately after the time of contact with the antimicrobial treatment material. The ice crystals in the foodstuff (202) inhibit absorption of the antimicrobial treatment material into the foodstuff.
