Abstract

Bacterial strains (32) from spoiled sardine were isolated and investigated for their ability to produce histamine and tyramine in histidine and tyrosine decarboxylase broth, respectively by a rapid high-performance liquid chromatography (HPLC) method. The predominant microflora of sardine consisted of the generaEnterobacteriaceae, Pseudomonas, Chryseobacterium, Vibrio, Photobacterium, andStenotrophomonas. In histidine-enriched broth, the highest levels of histamine were observed in Proteus mirabilis (5201.95 mg/L), followed by Enterobacter cloacae(2333.99 mg/L), whilst the lowest histamine accumulation was found for Kluyveraspp. and Listeria monocytogenes at the level of 0.38 and 0.45 mg/L, respectively. However, Pseudomonas oryzihabitans, Chryseobacterium indologenus and Vibrio vulnificus showed the highest accumulation of tyramine in tyrosine decarboxylase broth with values of 1648.85, 774.20 and 187.96 mg/L, respectively. Serratia liquefaciens produced more than 1000 mg/L putrescine in both enrichment broths, although Serratia rulnidace did not have the ability to produce amines (except for dopamine, serotonin and agmatine) in tyrosine decarboxylase broth. The study results show that P. mirabilis and Enterobacter cloacae, which were dominantly found in spoiled sardine, were strong amine producers.

Key words: Biogenic amines, histamine, tyramine, spoilage, sardine