Abstract

Samples of raw and traditional fermented milk ("lben") of both camels and cows collected from different zones of southern Morocco were analyzed to evaluate their microbiological quality and to isolate lactic acid bacteria (LAB) producing bacterio cin-like inhibitory substances (BLIS). The following groups of microorganisms were investigated: aerobic mesophilic flora, coliform, fecal coliform, casei n-degrading germs, staphylococci, lactic acid bacteria, yeasts and fungi. The analyzed samp les were generally highly contaminated and the microbial counts were clearly varying among samples. A total of 1000 strains randomly isolated from different samples were screened for the production of BLIS. 55 LAB isolates were shown to be active against at least one of the indicator strains: Bacillus subtilis , Staphylococcus aureus and E. coli . Among the active isolates, two strains called Q37 and Q310 were selected for their inhibitory activity, heat stability and pH acid resistance. They were identified as Streptococcus thermophilus , throughout API 20Strep and API 50CH tests. Both active strains lack haemolytic activity a nd were sensitive to most of the antibiotics tested. These characteristics insure their safe ty aspect and their po tential application in fermented food as starter and/or protective cultures.