The concentration of all organic acids was determined by HPLC. Prior to the assay, CFS from MRS (lactobacilli) and BHI (enterococci) cultures were deproteinized. In brief, 1 mL of sample was added to 2 mL of a solution in 1.8% Ba Ba(OH)2, adding 2 mL of a solution of 2% ZnSO4. The mixture was vortex shaken, allowed to settle for 10 min and centrifuged at 3500 g for 5 min. Each supernatant was filter sterilized (0.45 µm) before the HPLC analyses. The sample amount injected was 20 µL. The column temperature was 55 oC and the flow rate of the H 2SO4 10 mM mobile phase was 0.6mL/min. Detection was carried out by determining the refraction index using a 2142 LKB Differential Refractometer. The chromatography column (Rezec Organic Acid, Phenomenex) had a diameter of 7.8 mm and a length of 300 mm. Peak profiles, integration, and quantification were obtained with a CR601 Shimadzu chromatopac integrator (Shimadzu Corporation, Analytical Instrument Division, Kyoto, Japan). All tests were carried out induplicate.