Biogenic amine formation and oxidation by Staphylococcus xylosus strains from artisanal fermented sausages

Fifty strains of Staph. xylosus, isolated from artisanal fermented sausages in Southern Italy (Lucania region) were tested to verify their potential t o produce or degrade biogenic amines. Twenty-six strains analysed were not able to form amines, but seven had the potential to produce spermine and/or spermidine and, at lower levels, tryptamine and tyramine. By contrast, abo ut 80% of the strains that did not possess amino acid decarboxylase activit y, exhibited an ability to degrade histamine. The greatest histamine-oxidas e activity was present in the strains S81 (100% degradation), S206 (93%), S 79 (68%) and S90 (53%). The strain S142 exhibited a remarkably high potenti al to oxidase tyramine and histamine, reducing the initial concentrations b y 63 and 47%, respectively.