... other, its mirror image, is D-(-)-lactic acid or (R)-lactic acid. L-(+)-Lactic acid is the biologically important isomer. In animals, ... to over 20 mmol/L during intense exertion. Industrially, lactic acid fermentation is performed by Lactobacillus bacteria, among others. These ... blood loss due to trauma, surgery, or a burn injury. Lactic acid is primarily found in sour milk products, such as: ...