Abstract

The present study describes the composition of raw camel milk from south Tunisia in comparison with bovine milk and investigate the antimicrobial activity of isolated Lactic acid bacteria (LAB). The physical analysis of milk showed that camel milk was more acidic and viscous than cow milk while chemical composition showed that bovine milkwas richer in fats (40 ± 3.4 g/l) and dry matter (121.54 ± 8.1 g/l). Mean microbial load in camel milk was recorded as follows: (7 ± 3)× 10³ cfu/ml, (1.37 ± 12)× 10² cfu/mL  and(1.8 ± 3) ×10¹ cfu/mL for the total mesophilic count, LAB and Coliforms respectively and they were lower when compared to samples of bovine milk. A total of 50 strains of LAB was isolated from camel and bovine milk, out of which 15 strains were selected as the strongest acidifying abilities. Screening of those strains led to the isolation of two strains from camel milk (BL_C3 and BL_C9) demonstrated large and clear zones of inhibition of two indicators strains growth (Staphylococcus epidermidis CIP 106510 and Enterococcus faecalis ATCC 29212). Their antimicrobial compounds were detected in cell-free culture supernatant (CFS) after elimination of organic acids and hydrogen peroxide.

Key words: Camel milk, lactic acid bacteria, antimicrobial activity, microbiological quality, acidification ability.