Biogenic amine production by Morganella morganii and Klebsiella oxytoca in tuna

Biogenic amine formation in tuna inoculated with two micro-organisms reported as powerful in vitro histamine producers, Morganella morganii and Klebsiella oxytoca, was investigated. Inoculated and non-inoculated tuna samples were stored in ice, under refrigeration at 8-10degreesC and at 20+/-1degreesC. Ten biogenic amines were studied and changes were found only in cadaverine and histamine in inoculated samples. Therefore, the in vitro ability of K. oxytoca to form cadaverine and that of both microorganisms to form histamine was confirmed in inoculated samples. Storage temperature had a crucial effect on the amount and intensity of amine production. On the other hand, the potential ability of M. morganii to form putrescine was not shown in the inoculated samples, regardless of the storage temperature.