Tyramine Production by Enterococci from Various Foodstuffs: A Threat to the Consumers

Abstract

Tyramine is the most frequent biogenic amine found in cheese and is also frequently found in other fermented foods and beverages. In total 273 different strains of enterococci from various foodstuffs were studied. A multiplex PCR was designed for the genotypic differentiation of various enterococci strains at species level and for determination of the presence of tyramine producing (tyrdc) gene. E. faecalis and E. faecium were found to be prominent strains in dairy and meat products while, E. faecium and E. mundtii were found to be ruling in case of fruits and vegetables. HPLC analysis was carried out for determination of levels of tyramine. 211 i.e. 86.8% of samples were containing about 1000-1500 mg/l of tyramine, while 10 i.e. 4.1% were found to have tyramine in the range 100-500 mg/l. Negative samples showed 0 mg/l of tyramine.

Keywords

• tyrdc gene
• tyramine
• pcr, hplc
• enterococci