Food Microbiology

Lactobacilli are rods belonging to the Lactic Acid Bacteria (LAB), and includes: Gram-positive, catalase negative, non-motile, non-sporulating, facultative anaerobes, growing under microaerophilic to strictly anaerobic conditions. Recently, some research has been focused for selected strains from goat’s milk with a technological potential and safety, susceptible to be used as adjunct cultures in dairy products strains intended for the use in food systems as starters or probiotics adjunct culture should therefore be carefully examined following important criteria. This study is a widespread of our research that has of objective to identify and study in vitro the technological traits heterogeneity and their safety aspect of lactobacilli strains isolated from goat's milk samples collected in different regions of Algeria. Using API50 CHL system and 16S rDNA sequencing, 51 % of strains were assigned as L. plantarum, 34 % as L. pentosus, 7 % as L. rhamnosus and 8 % as L. fermentum. A large variability was noted for the acidifying capacity in skimmed milk after 6, 12 and 24 h of incubation. All strains expressed aminopeptidase activity against alanine-ρ-NA and leucine-ρ-NA at different levels. All strains were resistant to vancomycin and most of strains showed more susceptibility to β-lactam antibiotic. High susceptibility toward the inhibitors of protein synthesis was also observed. Minimum inhibitory concentrations data obtained revealed that isolates were susceptible to penicillin and chloramphenicol, and resistant to gentamicin and vancomycin. Minimum inhibitory concentration distribution of other antibiotics showed variability. The analysis of graphical representation of principal component analysis of technological properties of L. plantarum and L. pentosus strains showed diversity among the isolates. Finally, eight L. plantarum, four L. pentosus and two L. rhamnosus strains, could be good candidates as adjunct culture in dairy product in Algeria.