Tyramine degradation by micrococci during ripening of fermented sausage

Abstract

The ability of tyramine oxidase exhibiting strains of Micrococcus varians to degrade tyramine in vivo during sausage fermentation was investigated. Fermented sausage was produced with a tyramine forming strain of Lactobacillus curvatus which acquired a final tyramine concentration of 190ppm. The addition of either one of two strains of M. varians exhibiting a potential to oxidise tyramine decreased the amount of tyramine formed to 160 and 150ppm, respectively. No effect on growth of L. curvatus and pH development in the fermented sausage was observed when micrococci were present during a three weeks ripening period. Sausage fermentation was further carried out with a non-amine forming strain of L. sake and M. varians after addition of 100ppm tyramine to the raw material. The amount of tyramine in the end product was 60ppm, and during the first 10 days of ripening the decrease was faster on the outside of the sausage.