To provide a method for producing γ-aminobutyric acid, to provide a food, feed, fertilizer, agrochemical or the like, containing the γ-aminobutyric acid, to provide a food, feed, fertilizer, agrochemical or the like, obtained by the method, and to provide a method for economically and efficiently preserving a raw material selected from various food raw materials in a lactobacillus fermentation process, various un-used food raw materials, or their post-treated products, characterized by treating the preservation target by a decarboxylation enzyme reaction of lactobacillus in an anaerobic condition to prevent contamination with various bacteria.

This method for producing γ-aminobutyric acid is characterized by treating a food raw material which contains ≤20 w/v% of glutamic acid and/or its salt or to which the ≤20 w/v% of glutamic acid and/or its salt is added, with a lactobacillus having a glutamic acid decarboxylation enzyme-producing ability. In order to prevent nutritive substances, functional substances contained in the raw material, a heating temperature in a process for thermally treating the food raw material may suitably be adjusted, or the food raw material may not be heated. The formation of an anaerobic state due to the generation of carbon dioxide in the decarboxylation enzyme reaction of the lactobacillus fermentation can be utilized to achieve the practically sufficient preservation of the food and food raw material even in a non-closed container (opened container).