Evaluation of probiotic properties of Enterococcus faecalis and Enterococcus faecium species isolated from Pousti cheese of Gilan province in 2020

Pousti cheese is a traditional dairy product in different parts of our country. Enterococci are among the predominant bacteria in raw milk cheeses, such as pousti cheeses, which are even used in cheese as a starter or probiotic. The aim of this study was to isolate and identify Enterococcus faecalis and Enterococcus faecium strains with probiotic potential from Pousti cheeses in Gilan province. For this purpose, after isolation and detection of enterococci by phenotypic and biochemical methods, Survival under in-vitro conditions simulating the human GI tract (acid, pepsin, bile and pancreatin), antagonistic properties of isolates and their Auto-aggregation properties, and Co-aggregation with Escherichia coli and Salmonella enterica were evaluated. The results showed the presence of enterococci in 23 cheese samples (76.6%) which were confirmed by confirmational and biochemical tests as 29 isolates of Enterococcus faecium (50%) and 22 isolates of Enterococcus faecalis (37.9%). Totally, 14 samples (27.4%) were able to survive in the presence of acid and pepsin and were selected for the further steps. Finally, 12 isolates well tolerated the presence of bile and pancreatin and their antimicrobial and aggregation properties were evaluated. The isolates showed significant anti-listeria effects and also had a high auto-aggregation power (53.95%) and their co-aggregation effect was higher with Salmonella enterica than Escherichia coli. From the results it can be concluded that some native isolates of Enterococcus faecalis and Enterococcus faecium in Pousti cheese have good potential for use as probiotics.