PROBLEM TO BE SOLVED: To provide a technique for producing a preserved food which can maintain the original flavor and palatability of a food material and can simultaneously be preserved over a long period. SOLUTION: This method for the preservation treatment of a food material, comprising immersing the food material processed into a prescribed shape in the aqueous solution of a mixture of a hydrochlorite with hydrochloric acid, washing the food material with water, further immersing the food material in a 95 deg.C acetic acid aqueous solution for 10 min, and then washing the food material with water.