Lactic acid is an alpha-hydroxy acid produced naturally via fermentation of carbohydrates by lactic acid bacteria. It exists as L- and D-enantiomers, with the L-form predominant in biological systems. Used extensively as a food preservative, acidulant, and flavor enhancer in dairy, meat, and baked goods. It contributes to sour taste and acts as a pH regulator. In metabolism, it forms during anaerobic glycolysis. Chemically, it is a viscous, colorless to yellow liquid that is hygroscopic and miscible with water and ethanol. Industrially produced by fermentation or chemical synthesis from acetaldehyde.