Survie in vitro de souches lactiques locales aux conditions gastriques simulées

Abstract

The main goal of this study is in vitro evaluation of survival for nine local lactic strains isolated from cow's milk: (LbN01, LbN05,09,10,11,12,13,14,15), in the simulated gastric conditions, namely: acidity, gastric juice (pepsin), presence of bile salts 0.5% and test adhesion . A strain of Lactobacillus plantarum is used as a control strain. Resistance test in different pH, indicate the viability of all strains at pH = 5 (survival/24H), while at pH = 1.5 and 3 the resistance lasted at least 6h of incubation. The results of plate counting method on simulated gastric juice medium (1.3% pepsin + pH2.5) and on MRS medium supplemented with 0.5% bile salts; showed a very high survival rates in used lactic strains, and LbN11 was the most strain that have viability rate greater than 100%. Test adhesion showed that most of strains could adhere to epithelial cels