Characterization and evaluation of lactic acid bacteria isolated from goat milk

Abstract

The aim of this study was to characterise and select Lactic Acid Bacteria (LAB) from goat milk with potential probiotic use and to evaluate the safety of these cultures in artisanal cheeses. The isolates of LAB were subjected to simulation of tolerance to the gastrointestinal tract, haemolytic test, antimicrobial susceptibility, antibacterial activity, EPS production, gas production, evaluation of proteolytic activity, diacetyl production and tolerance to NaCl. The genus and species of the selected LAB isolates were confirmed using molecular identification. Three goat cheeses (1, 2 and control) were manufactured to evaluate the inhibitory action of LAB against Escherichia coli. Subsequently, all cheese samples underwent bacterial enumeration and physical–chemical analyses. Statistical analysis was performed. UNIVASF CAP 14 and 20 were differentiated by survival up to pH 2 and pancreatin, resistance to NaCl and antibacterial activity against Klebsiella pneumoniae. UNIVASF CAP 4 and 29 were characterised by resistance to intestinal juice and antibacterial activity against Salmonella Typhi and Listeria monocytogenes. UNIVASF CAP 27, 38, 43 and 139 exhibited diacetyl production, antibacterial activity against Bacillus cereus, Staphylococcus aureus and Enterococcus faecalis. UNIVASF CAP 35 and 138 were characterised by proteolytic activity, EPS production, antibacterial activity to E. coli and Shigella flexneri. A cocktail of these 10 isolates with potential probiotic properties were inoculated in artisanal goat cheese and improved microbiological safety of product against E. coli.