3. Result and discussion
3.1. Biogenic amine production by isolates in histidine enrichment decarboxylase broth
HPLC shows that a number of S. thermophilus isolates produced biogenic amines in histidine decarboxylase (HDB) (Table 1). All S. thermophilus isolates had the ability to produce ammonia. Thirtynine strains of S. thermophilus produced below 100 mg/L of ammonia, while the other strains produced more than 100 mg/L