Twelve different biogenic amines formation in 58 isolates of Streptococcus thermophilus from home-made
natural yogurt were investigated in histidine (HDB) and lysine decarboxylase broth (LDB). All
S. thermophilus isolates had an ability to produce twelve different biogenic amines in HDB and LDB. Most
of the S. thermophilus isolates formed low amounts of histamine (1–50 mg/L) from histidine. Apart from
one isolate, S. thermophilus produced tyramine at low (47 isolates) and medium (10 isolates) levels. The
amount of each specific biogenic amine produced by S. thermophilus was generally lower than
100 mg L1. Also, the presence of hdcA gene was investigated using PCR technique and relation between
gene and histamine production was conducted in S. thermophilus isolates. This study showed that most of
the S. thermophilus isolates have the ability to form biogenic amines, especially histamine, and tyramine,
which is an important consideration when selecting strains as starter cultures.