An enzymatic test kit for the determination of D-lactic acid in wine and other liquid samples and other samples. Contains buffer, NAD Substrate, enzymes, and standard as ready-to-use aqueous solutions and suspensions. Lactic acid is found in very low concentration in grapes. Between 0.1 – 0.4 G/L of lactic acid is typically found in wine (absent mali-lactic fermentation.) Infrequently, and in the presence of high residual sugar and pH, ubiquitous lactic bacteria (typically of Leuconostoc, Pediococcus, or Lactobacillus genera) are involved in wine spoilage; significant amounts of D-Lactic acid and acetic acid can be produced by metabolism of sugars, glycerol, tartaric or citric acid in the wine. D-Lactic acid and detrimental by-products of lactic bacterial action can be largely prevented by filtration and increased sulfite concentration.