Formation of biogenic amines by proteolytic enterococci during cheese ripening

Six strains of Enterococcus faecalis and three strains of E faecium were in vestigated for their proteolytic activity and ability to decarboxylate the amino acids lysine, histidine, tyrosine, ornithine and phenylalanine. All s trains tested displayed cell wall-associated proteolytic activities, and th ree E faecalis strains displayed additionally extracellular proteolysis. No ne of the strains tested was able to form putrescine, histamine or cadaveri ne. Eight strains decarboxylated tyrosine, and two strains off faecalis and one strain of E faecium formed phenylethylamine, Gouda cheese was produced from milli supplemented with two strains of E faecalis (10(7) cfu ml(-1)). Both strains were proteolytic and potent tyramine formers. Final viable co unts of 10(9) cfu g(-1) and tyramine concentrations of 477 mg kg(-1) were d etected after a 12 week ripening period. (C) 1999 Society of Chemical Indus try.