Potential Starter Candidate Based on Safety and Technological Evaluation of <i>Lactococcus lactis</i> from Kimchi, Korean Traditional Fermented Vegetables

Continuous screening of suitable starter candidates for fermented foods necessary based on safety and technological evaluations. For this purpose, 34 <i>Lactococcus lactis</i> strains isolated from kimchi were evaluated to select potential starter candidates. All tested strains were susceptible to ampicillin, chloramphenicol, clindamycin, erythromycin, gentamicin, kanamycin, and vancomycin. However, 32 strains exhibited resistance to streptomycin, while 2 showed resistance to tetracycline. None of the strains demonstrated hemolytic activity. All strains exhibited protease activity and acid production, but none displayed amylase or lipase activity. Notably, all strains exhibited antibacterial activity against <i>Listeria monocytogenes</i> ATCC 19111 and <i>Salmonella enterica</i> KCCM 11862. Furthermore, antibacterial activity was observed in 70.6%, 79.4%, 79.4%, 73.5%, and 32.4% of strains against <i>Bacillus cereus</i> KCCM 11341, <i>Enterococcus faecalis</i> KCTC 2011, <i>Staphylococcus aureus</i> ATCC 12692, <i>Flavobacterium</i> sp. KCCM 11374, and <i>Vibrio parahaemolyticus</i> KCTC 2729, respectively. Based on these assessments, <i>L. lactis</i> strain DMLL15 was identified as the most promising starter candidate. This strain was sensitive to nine antibiotics, exhibited non-hemolytic activity, demonstrated strong protease activity and acid production, and displayed antibacterial activity against seven pathogenic and spoilage bacteria. These findings support the safety assessment results and highlight the potential application of <i>L. lactis</i> DMLL15 as a starter candidate in the food industry.