The present invention provides fermented food or drink obtained by fermenting a medium which includes vegetative raw material, by using Lactobacillus brevis, and the number of living cells of the Lactobacillus brevis in obtained fermented product is 1 ×10 8 cfu/ml or greater. The number of living cells does not significantly change after being preserved at 10°C for three weeks, and excellent taste and flavor of the fermented food or drink do not deteriorate. The method for producing the fermented food or drink product includes the steps of: adding a strain of Lactobacillus brevis to a medium having an adjusted pH of 4.6 to 7.0, which includes: a vegetative raw material in an amount of 50% or more converted to a juice thereof； and 0.2 to 2.0% by mass of malic acid or 2.0 to 20.0% by mass of fructose, to ferment the medium so that the pH thereof becomes 4.3 or greater and less than 7.0； and adjusting a pH of a fermented product to 3.3 to 4.1 by using an acid.
