Changes in biogenic amines of major Portuguese bluefish species during storage at different temperatures

Changes in histamine (Him), cadaverine (Cad), putrescine (Put), agmantine (Agm) and volatile basic nitrogen (VBN) contents were examined in sardine, Atlantic horse mackerel, chub mackerel and Atlantic mackerel, during ice storage and storage at room temperature. Him formation as well as other amines varied greatly with species of fish and storage conditions. The levels of Him, Cad, put and VBN increased gradually in all the fish species as decomposition progressed, regardless of storage temperatures. In iced fish, amine production was considerably reduced and Him concentration was, in general, lower than 100 mg/Kg. During ice storage amines increased slowly until day 7, after which a significant rise was detected. In comparison with the other fish species higher levels of Him, Cad and put were determined in Atlantic mackerel. At room temperature Him, Cad and put were produced at the highest concentrations in chub mackerel, followed by sardine, Atlantic mackerel and Atlantic horse mackerel. Him concentration maximum exceeded allowable limits for human consumption in the first three species after 24h of storage at room temperature. No correlation was observed for Him or other amine levels and the degree of fish decomposition. Thus, the use of Him or other amines as a freshness index of the studied fish species was not considered appropriate.