Biogenic amines during ripening in 'Semicotto Caprino' cheese: role of enterococci

Semicotto Caprino is a traditional goats' cheese manufactured in the Basili cata region (Southern Italy). Four experimental lots of cheeses were produc ed from separate batches of milk. All the biogenic amines monitored increas ed during ripening, the most abundant at each ripening time being putrescin e, followed by tryptamine and tyramine. Histamine was not detected at 15 da ys, but it reached 104 mg kg(-1) cheese at the end of ripening (60 days). A good correlation between free amino acids and total biogenic amines produc tion was found. Strains of enterococci were isolated from all batches of go ats' cheese and characterized for amine production and proteolytic activity . HPLC analysis showed that the isolates produced 2-phenylethylamine, trypt amine, cadaverine, spermidine and, sometimes, spermine. The high amine-posi tive strains were also highly proteolytic. In the growth medium with a mixt ure of amino acid precursors added, the tested isolates produced more amine s, even if at different levels.