Isolation and Characterization of Bacteriocinogenic Enterococcal and Lactococcal Strains from South of Morocco Dairy Product

Abstract

Aim: To investigate the occurrence of bacteriocinogenic lactic acid bacteria (BAL) in different animal’s milk of the south of Morocco. Place and Duration of Study: Laboratory of Microbial biotechnologies and plant Protection, Faculty of Sciences, and Bioprocess and Environment laboratory (LASIME), EST-Agadir, Ibnou Zohr University, Agadir, Morocco, between January 2014 and January 2016. Methodology: A total of 2000 different colonies, isolated from 42 samples of dromedary, ewe’s, goat and cow spontaneously fermented milk collected from some southern regions of Morocco, were tested for antimicrobial activity. Three indicator strains were used; Listeria innocua, Bacillus subtilis and Enterococcus hirae. The selected strains are phenotypically and biochemically identified, especially by API 20 Strep galleries. In addition, the sanitary and technological aspects of these strains are studied. Results: Among the active strains 150 strains were selected, and 91% among them were identified as lactic acid bacteria. Out of these, 11 strains isolated from dromedary and ewe’s milk are shown to be active by the agar well diffusion assay (AWDA). Seven (7) strains were identified as Enterococcus faecium, three (3) as Enterococcus faecalis and only one (1) strain was identified as Lactococcus lactis. The twelve strains are active against a wide range of pathogenic and spoilage bacteria, including Listeria monocytogenes, Staphylococcus aureus and Escherichia coli. In addition, all of these strains shown to lack haemolytic, decarboxylatic, proteolytic and lipolytic activities and to be susceptible to most tested antibiotics. Conclusion: These results suggest a potential application of isolated strains of lactic acid bacteria in bio-preservation of fermented foods especially dairy products.