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ITALIAN JOURNAL OF FOOD SCIENCE, vol.37, no.3, pp.310-324, 2025 (SCI-Expanded, Scopus)
Table olives are among the most significant traditional fermented vegetables in Türkiye, with their global consumption steadily increasing. This study aimed to investigate the presence of biogenic amine (BA)-producing Enterococcus strains in traditional table olives. A total of 186 probable enterococcal isolates were identified from 460 table olive samples, including 240 green and 220 black olives. The ability of Enterococcus spp. to produce five BAs, including tyramine, cadaverine, putrescine, tryptamine, and histamine, was evaluated. The decarboxylase activity of Enterococcus isolates was analyzed using a modified decarboxylase medium. Among these, 71 isolates were determined as BA producers. Species-level identification through 16S rDNA sequence analysis classified these strains as E. faecium (20 isolates), E. faecalis (31 isolates), and E. lactis (20 isolates). Concentrations of BAs were quantified through high-performance liquid chromatography. The maximum concentrations of tyramine, cadaverine, putrescine, tryptamine, and histamine detected in the samples were 257.939 mg/L, 13.923 mg/L, 139.620 mg/L, 30.562 mg/L, and 7.985 mg/L, respectively. The total content of BAs produced by Enterococcus strains from green olives varied between 1.018 mg/L and 259.324 mg/L, while those from black olives ranged from 1.831 mg/L and 214.678 mg/L. Predominant BA detected in green olives was tyramine (257.939 mg/L). Similarly, in black olives, the highest BA levels were recorded for tyramine (207.618 mg/L). These findings highlight the significant presence of BA-producing Enterococcus strains in table olives, emphasizing the need for monitoring and control strategies to ensure food safety.