Safety, Antagonistic Activity, and Probiotic Properties of Lactic Acid Bacteria Isolated from Jeotgal, Korean Fermented Seafoods

Probiotics are in high demand in the health functional food market as they effectively inhibit pathogens and improve host health. Therefore, in order to develop novel probiotic strains, new strains were isolated from various type of jeotgal, traditional Korean fermented seafood products, and their safety and probiotic properties have been evaluated. Based on 16S rRNA gene sequence analysis, six strains (JRD1, <i>Pediococcus pentosaceus</i>; JRD2, <i>Lactiplantibacillus plantarum</i>; JRD6, <i>Pediococcus acidilactici</i>; CLJ21, <i>Lactiplantibacillus plantarum</i>; CLJ24, <i>Pediococcus pentosaceus</i>; CLJ28, <i>Leuconostoc mesenteroides</i> subsp. <i>dextranicum</i>) were selected and subjected to further analysis. As a result, all six strains did not show hemolytic activity, antibiotics resistance, and cell cytotoxicity, confirming that they are safe for human use. Among them, JRD1, JRD6, and CLJ24 exhibited high survival rates under simulated gastrointestinal conditions. Additionally, these three strains demonstrated strong adhesion abilities on HT-29 cells, with values of 6.02, 5.77, and 5.86 log CFU/mL, respectively. Furthermore, JRD1, JRD6, and CLJ24 showed relatively high antagonistic activity against both <i>Salmonella</i> Typhimurium and <i>Staphylococcus aureus</i> through competition, exclusion, and displacement of their adhesion. Interestingly, cell-free supernatants (CFS) from three strains effectively inhibited the growth of both <i>S</i>. Typhimurium and <i>S. aureus</i>. Furthermore, CFS of CLJ24, JRD1, and JRD6 demonstrated anti-inflammatory effects in intestinal epithelial cells. The results suggest that CLJ24, JRD1, and JRD6 have potential to be development as functional probiotic strains with both antibacterial and anti-inflammatory activities.