In vitro probiotic properties of Lacticaseibacillus casei CB054 from anaerobically fermented bovine colostrums

ABSTRACT: This study evaluated Lacticaseibacillus casei CB054 (Lsc.CB054) from anaerobically fermented bovine colostrum for its in vitro probiotic potential. We performed a series of in vitro tests to verify the probiotic capacity and safety of the bacterial isolate. These tests included the evaluation of hemolytic capacity, cytotoxicity, antimicrobial susceptibility, tolerance to adverse conditions, survival in the gastrointestinal tract, antagonistic activity against pathogenic bacteria, and auto- and co-aggregation abilities. The results demonstrated no hemolytic activity, and the microorganism did not exert a cytotoxic effect on Madin-Darby Bovine Kidney cells. It was observed that Lsc.CB054 was susceptible to nine (9/10) of the antimicrobials tested, showing resistance only to sulfonamide. When subjected to various acidic conditions, bile salts, and phenol, the survival rate of Lsc.CB054 was ≥ 8 log CFU/mL. In simulations of the intestinal tract, the presence of food with bile did not affect the multiplication of the bacterium; however, the duration of exposure impacted bacterial multiplication. Conversely, no viable cells of Lsc.CB054 were observed after 30 minutes of exposure to the simulated gastric tract without food. The isolate displayed antagonistic activity against Salmonella Typhimurium (18.5 mm), Staphylococcus aureus (23.5 mm), Listeria monocytogenes (15.5 mm), and Escherichia coli (18.0 mm), and exhibited auto-aggregation (> 75%) and co-aggregation with L. monocytogenes (> 79%). According to the results of this in vitro study, the probiotic potential of Lsc.CB054 is revealed.