The importance of lactic acid in the food industry is certainly correlated with its peculiar chemical and physical properties. According to the Joint FAO/WHO Food Standards Programme, lactic acid isomers and the racemic mixture can be used as acidity regulator in certain foods with the aim of contrasting certain acid-sensitive microorganisms. As a result, the description of food-related uses of lactic acid should involve also peculiar chemical and physical features. This chapter would give a brief and accurate overview of chemical and physical features of this additive. In addition, the chemical synthetic processes for the production of the so-called milk acid are described. Finally, fermentative pathways and related industrial strategies are discussed.