Comprehensive genotypic and phenotypic safety assessment of Lactococcus lactis subsp. lactis CAB701 as a probiotic candidate
摘要
This study evaluated the safety of Lactococcus lactis subsp. lactis CAB701 for probiotic application using integrated phenotypic and genotypic approaches. Phenotypic evaluations demonstrated the absence of hemolytic activity, bile salt deconjugation, mucin degradation, gelatin liquefaction, D-lactic acid production, and β-glucuronidase activity. Minimum inhibitory concentration testing showed that the strain was susceptible to clinically relevant antibiotics, with all values below the European Food Safety Authority cut-off thresholds. In vitro assays further confirmed that L. lactis subsp. lactis CAB701 did not exert cytotoxic effects on Caco-2 intestinal epithelial cells and did not produce biogenic amines. Whole-genome sequencing revealed no acquired antimicrobial resistance genes, virulence determinants, or genes associated with toxic metabolite production. Collectively, these phenotypic and genomic findings indicate that L. lactis subsp. lactis CAB701 fulfills established safety criteria and supports its suitability for use as a probiotic strain.