Characterization and detection of Lactococcus lactis subsp. lactis Sb 2 as probiotic starter in beef Nham

摘要

The probiotic agent designated as Sb 2, isolated from seabass (Lates calcarifer), was identified as Lactococcus lactis subsp. lactis by 16s rDNA. Bacteriocin gene of this strain was identified as Nisin A by PCR technique using specific primer. This strain was applied as starter culture in beef Nham. Survival of L. lactis subsp. lactis Sb 2 during Nham fermentation at 30°C for 3 days was detected by PCR-RAPD fingerprint technique. The 3 distinct DNA bands about 1200, 2000 and 3000 bp, which corresponded to DNA fingerprint of this strain, were found from dayl to day 3 of fermentation. This confirmed the survival of L. lactiss subsp. lactis Sb 2 during Nham fermentation process.