A Bifidobacterium Strain with Antibacterial Activity, Its Antibacterial Characteristics and In Vitro Probiotics Studies

The search for natural antimicrobials has intensified with rising food safety demands. This study evaluated 23 probiotic strains, identifying <i>Bifidobacterium</i> sp. strain TF04 as a potent inhibitor against pathogens, with inhibition zone diameters of 12.85 ± 0.12 mm (<i>Escherichia coli</i>), 14.85 ± 0.10 mm (<i>Staphylococcus aureus</i>), and 17.50 ± 0.23 mm (<i>Staphylococcus epidermidis</i>). Preliminary analysis shows that the main antibacterial compounds produced by TF04 in the process of bacterial growth inhibition are antibacterial active proteins. TF04 exhibits optimal bacteriostatic activity within the pH range of 2-4, with a notable decline in effectiveness as the pH value increases. At the same time, the bacteriostat produced by TF04 showed strong thermal stability and ultraviolet stability. TF04 demonstrated excellent probiotic potential: surviving acidic (pH 2.0, >45% viability) and bile conditions (3% bile salts, >55% survival). It showed strong auto-aggregation (40.10%) and hydrophobicity (>30%), indicating gut colonization potential, along with notable antioxidant capacity. Safety was confirmed by absent hemolytic and gelatinase activities. These properties position TF04 as a promising multifunctional candidate for food preservation, combining antimicrobial efficacy with probiotic benefits. Further studies will purify its bioactive compounds and validate applications in food systems.