To provide a method for preserving a food capable of preserving the food permanently without requiring a conventional sterilization condition by adding a combination containing each specific lipo soluble sodium salt with non-lipo soluble acid to a food having a prescribed acid pH region to kill microorganisms (spores) in the food.

This method for preserving a food comprises adding a combination containing (i) ≥1 sodium salt of a lipo soluble and as necessary hydroxy- sobstituted 2-3C fatty acid (e.g.; acetic acid), (ii) ≥1 non-lipo-soluble acid agent selected from citric acid, tartaric acid, ascorbic acid or their mixture having a lower pKa than those of a 2-3C fatty acid and capable of forming a complex with a divalent alkaline earth metal ion, and as necessary (iii) a sodium salt of the acid agent of an adding amount, to a food having 4.5-7 pH range and containing ≥0.4 wt.% undissociated fatty acid in an amount based on the weight of the food (e.g.; a sea food), and further preferably adding a reducing acid agent such as ascorbic acid for preserving the food.