Enterococci from Italian dairy products


TITOLO: Technological and molecular characterisation of enterococci isolated from north-west Italian dairy products

RIVISTA: International Dairy Journal

NUMERO RIVISTA: n. 16, p. 867-875

In the present study, 68 enterococcal isolates collected from dairy products of north-west Italy, were characterized by using randomly amplified polymorphic DNA-PCR (RAPD-PCR) and screened for the presence of technologically relevant biochemical properties. After the comparison of RAPD-PCR profiles with the profiles of the enterococcal type strains, isolates were assigned to the species Enterococcus faecalis (35 isolates), E. faecium (27 isolates) and E. durans (6 isolates). Phenotypic identification based on carbohydrate fermentation profile galleries gave different results from RAPD-PCR in 17.6% of the cases (10 E. faecium and 2 E. durans isolates). Regarding biochemical activities, the majority of the strains displayed weak acidification activity in milk. High values for redox activity were detected for 80% of E. faecalis isolates, while E. faecium resulted the most lipolytic species. Proteolytic activity was generally low, except for 10 E. faecalis isolates that displayed values ≥0.5 mg tyrosine 5mL-1 of milk. Finally, none of the isolates carried vanA or vanB (vancomycin resistance) genetic determinants.

AUTORI: Stefano Morandi, Milena Brasca, Christian Andrighetto, Angiolella Lombardi, Roberta Lodi