Effects of tyrosine decarboxylase negative strains from Harbin dry sausage on the growth and tyramine production of foodborne pathogens

The effect of tyrosine decarboxylase negative strains from Harbin dry sausage on the growth and tyramine production of foodborne pathogens (FBP) was evaluated. Lactobacillus paraplantarum, Lactobacillus curvatus, Lactobacillus sakei, Lactobacillus paracasei, Lactobacillus plantarum and Staphylococcus epidermidis were screened as tyrosine decarboxylase negative strains by thin layer chromatography, HPLC, and PCR. High tyramine degradation rates were observed in S. epidermidis (21.73%), L. sakei (20.02%), and L. curvatus (17.66%) (P < 0.05). In particular, S. epidermidis exhibited significant inhibition on the growth of L. monocytogenes, E. coli, and S. paratyphi B, and production of tyramine by FBP (P < 0.05). Consequently, S. epidermidis, L. sakei, and L. curvatus could be used in downstream research to ferment Harbin dry sausage and control tyramine production.