CHANGES IN BIOGENIC-AMINES AND MICROBIOLOGICAL ANALYSIS IN ALBACORE (THUNNUS-ALALUNGA) MUSCLE DURING FROZEN STORAGE

Albacore specimens of extra quality were analyzed for their biogenic a mine contents after 1, 3, 6, and 9 months of frozen storage at -18 deg rees C or -25 degrees C. A high-performance liquid chromatography meth od involving a linear elution gradient was optimized for the identific ation and determination of putrescine, cadaverine, histamine, spermidi ne, and spermine in albacore tuna. Putrescine was the biogenic amine t hat showed the highest increase, reaching concentrations of 59.04 ppm (815% of the initial level) and 68.26 ppm (942% of the initial level) in the white muscle of albacore after 9 months of frozen storage at -1 8 and -25 degrees C, respectively. Cadaverine, histamine, and spermidi ne concentrations were below 3, 5, and 11 ppm, respectively, after 9 m onths of frozen storage, while spermidine underwent a significant decr ease at both storage temperatures. Microbiological analysis confirmed the absence of species of Enterobacteriaceae in 75% of the albacore sp ecimens after 9 months of frozen storage; coliforms were always below 3 CFU/g. The survival rate of the psychrotrophic microorganisms after 9 months of frozen storage at -25 degrees C was 4.6%, while 38.9 and 9 2.1% of the aerobic mesophiles present in the white muscle of albacore before freezing survived 9 months of storage at -18 and -25 degrees C , respectively.