Author(s)
Deepthi Gunasena, Sharini Samaranayake
Abstract
The excessive use of antibiotics to control foodborne pathogens has contributed to the emergence of antibiotic-resistant Listeria monocytogenes, posing a significant global public health concern. This study aimed to evaluate the potential of native Lactobacillus species as natural antibacterial agents against L. monocytogenes. Cell-free supernatants (CFS) of nine Lactobacillus strains—comprising L. plantarum, L. fermentum, and L. acidophilus—isolated from traditionally fermented buffalo curd in Sri Lanka were tested for antagonistic activity against L. monocytogenes NCTC 11994 using the agar well diffusion method on Brain Heart Infusion (BHI) agar. Among the tested strains, L. plantarum T3b showed no inhibition, while the remaining eight strains exhibited significant antagonistic activity, as confirmed by statistical analysis. The findings indicate that the antagonistic effect is highly strain-specific, aligning with previously published data. Moreover, the results highlight the potential of traditional Sri Lankan buffalo curd as a source of functional probiotic strains with bio-preservative applications. This study contributes to the growing body of research supporting biological alternatives for managing foodborne pathogens and underscores the relevance of indigenous fermented foods in public health interventions.