EVALUATION OF POST-ACIDIDIFICATION AND VIABILITY OF LACTIC BACTERIA USING TRADITIONAL METHOD AND SYSTEM COMPACT DRY® TC DURING REFRIGERATED STORAGE YOGURT

Abstract

 Post-acidification and viability of lactic acid bacteria (LAB) of commercial yogurts were examined during 42 days of refrigerated storage. The ef? ciency of Compact Dry® TC associated with Man Rogosa Sharpe (MRS) broth at pH 5.4 was evaluated to enumerate LAB. Aliquots were submitted to dilution and plated simultaneously for LAB enumeration at MRS plates incubated under anaerobiosis and at Compact Dry® TC plates incubated under anaerobiosis in two distinct atmospheres conditions; with microaerfilia generator or with PVC involving the plates. MRS broth at pH 5.4 was employed for the last dilution inoculated on Compact Dry® TC. After 48 hours, the formed colonies were enumerated and were made Gram test, catalase and coagulase. The counts were compared by analysis of variance (p<0.01). The pH value showed reduction during the refrigerated storage. Results indicated that Compact Dry® TC associated to MRS at pH 5.4 and involved by PVC can be considered as a suitable alternative to conventional methods for LAB enumeration in yogurts.