Technological Aptitude and Applications ofLeuconostoc mesenteroidesBioactive Strains Isolated from Algerian Raw Camel Milk

Abstract

Two strains (B7 and Z8) of theLeuconostoc mesenteroidessubspeciesmesenteroidesthat were isolated from Algerian camel milk from an initial pool of 13 strains and demonstrated a high ability to inhibit the growth ofListeriaspp. were selected and characterised at the phenotypic and genotypic levels. Probiotic profiling and inhibition spectra against food borne pathogens in mixed cultures were also investigated. The bacteriocin produced byL. mesenteroidesstrain B7 was identified as leucocin B by specific PCR.In vitrostudies demonstrated that bothLeuconostoc mesenteroidesstrains exhibited a marked probiotic profile, showing high survival at low pH (2-3 and 4) in the presence of 0.5%, 1%, and 2% of bile salts and at pH 3 in the presence of 3 mg/mL pepsin. Susceptibility testing against antimicrobial agents was also performed for both strains. When tested in a mixed culture withListeria innocua,Listeria ivanovii, orStaphylococcus aureus, strain B7 reduced the numbers of these species by 1.87, 1.78, and 1.38 log units, respectively. Consequently, these two strains were found to possess good probiotic propertiesin vitroand a high capacity forListeriaspp. inhibition in mixed cultures. Therefore, these strains have a favourable technological aptitude and a potential application as novel probiotic starters.