Hemolytic activity, production of thermonuclease and biogenic amines by dairy enterococci

摘要: Seventy-five strains of enterococci isolated from dairy products and belonging to Enterococcus faecalis faecium were screened for hemolytic activity production deoxyribonuclease (DNase), thermonuclease (TNase) biogenic amines. Although 4 out 75 exhibited β-hemolysis on blood agar, DNase or TNase-producers not detected. MDA (Modified Decarboxylating Agar) medium supplemented with 2% L-tyrosine as precursor allowed a large number tyrosine-decarboxylating be recognized. After incubation in milk containing free amino acids precursors (200 ppm), the amines was quantified by HPLC confirmed tyramine, whereas histamine never It is suggested that represent possible group food grade microorganisms.