The Precursor of Benzoic Acid in Fermented Milk

In market fermented milk approximate ten ppm level of benzoic acid is detected commonly. The previous paper has indicated the presence of benzoic acid in skimmilk as the material of fermented milk, and also benzoic acid as a fermented productaby Lactobacillus in skimmilk medium. This paper showed that the precursor of benzoic acid, metabolite by lactic acid bacteria, is hippuric acid. It was found that when Lb. casei was grown in a skimmilk medium, benzoic acid was formed in the culture broth while hippuric acid disappered. The conversion of hippuric acid into benzoic acid was demonstrated with a good equivalent relation between the amount of hippuric and benzoic acids before and after incubation. Such activity of hippuric acid degradation was confirmed to be present widely in Lactobacillus, Streptococcus and Leuconostoc.