Antibacterial activity of lactic acid bacteria isolated from Camel Milk

Abstract

The objective of this study is to investigate the antibacterial activity of lactic acid bacteria isolated from camel milk. The physicochemical analysis of camel milk collected from the Djelfa region in central Algeria provided the following findings: the pH value was measured at 6.29, density at 1.028, acidity level at 16, dry matter content at 8.2637, fat content at 0.94, solids-not-fat (SNF) content at 6.98, protein content at 2.57, total solids at 17.4, lactose content at 3.84, conductivity at 8.58, added water content at 18.26, and a freezing point ranging from -0.4 to -0.525. For the characterization of lactic acid bacteria microflora present in the collected camel milk, selective media (MRS and M17) were used in the isolation. Microscopic identification revealed the presence of Lactobacillus and Streptococcus isolates, which aligns with previous research indicating the presence of these bacteria in camel milk. Camel milk is recognized for its high concentration of antibacterial molecules such as lysozymes, bacteriocins, lactoferrin, and more. To demonstrate this unique quality of camel milk, the lactic acid bacteria strains were evaluated for their antagonistic activity against four pathogenic bacteria: Escherichia coli (ATCC 259222), Pseudomonas aeruginosa (ATCC 9027), Bacillus cereus (ATCC 14579), and Staphylococcus aureus (ATCC 43300) using the disc diffusion method. The lactic acid bacteria strains exhibited significant inhibition zones against all tested pathogenic strains, with diameters ranging from 7 to 16 mm. Notably, a Lactobacillus strain demonstrated the largest inhibition diameter