Screening and Safety Evaluation of Potential Probiotic Lactobacillus plantarum in Sichuan Paocai

In order to screen L. plantarum with potential probiotic effect and safety, 114 strains of L. plantarum isolated from Sichuan Paocai were used as starting strains to conduct acid resistance, bile salt tolerance, resistance to simulated gastrointestinal fluid, auto-aggregation ability, pathogenic bacteria co-aggregation, antibiotic resistance and hemolytic research. After culturing in pH2.0 acidic conditions and 0.2% bile salt concentration, 13 strains with better tolerance were initially screened. The 13 strains were tested with simulated gastroenteric fluid, aggregation capacity, antibiotic resistance and hemolysis. The results showed that 13 strains simulated gastrointestinal fluid tolerance survival rate was higher than 75%, auto-aggregation ability 23%~52%, and the co-aggregation ability of pathogenic bacteria Listeria monocytogenes and Escherichia coli were 10%~29% and 16%~37%. The results of drug sensitivity and minimum inhibitory concentration (MIC) tests showed that the potential strains showed similar resistance to 10 common antibiotics in drug susceptibility and minimum inhibitory concentration (MIC) experiments. They were sensitive to β-lactam and amido alcohol antibiotics, and had strong resistance to aminoglycosides, quinolones, glycopeptides, macrolides and tetracycline antibiotics. There was no hemolysis phenomenon, indicating high safety. Therefore, the 13 strains of L. plantarum obtained from the primary screening had potential probiotics and high safety, and the research results would provide strain resources for the development of probiotics.