HISTAMINE LEVEL AND HISTAMINE-PRODUCING BACTERIA ISOLATED FROM SALTED AND FREEZE SARDINE FISH (Sardina spp.)

Abstract

Histamine is the biogenic amine responsible for scombroid poisoning in various types of fish and fish products. The study evaluated histamine content and bacteriological quality of salted and freeze sardine samples. All fish samples were cultured on Reinforced Closterdial medium; mannitol salt (MS) agar and violet red bile glucose (VRBG) agar, the positive colonies were sub-cultured on histamine-forming bacterium agar, followed by biochemical and PCR identification. Production of histamine in the fish muscles was measured by high performance liquid chromatography. The mean histamine values were about; 8.25 mg/100g. The mean of total aerobic counts was; 4×104 ± 2.1×104 while, the total anaerobic count; 5×104 ±1.2×103 Log CFU/g. Enterobacteriacea spp. about; 5×104 ±2.5×104 Log CFU/g while, the mean value of Staphylococcus spp. about; 3×104 ±3.7×104 Log CFU/g. The mean value of histamine-forming bacterial were; 3.3×106 Log CFU/g. Molecular Identification For Enterobacteriaceae were Klebsiella pneumonia, Staphylococcus xylosus, Escherichia coli and Enterobacter cloacae. We concluded that during storage, there was a positive relationship between the histamine levels and the histamine-forming bacteria (HFB) numbers, while, histamine and the bacteria forming histamine were recorded in all examined sardine samples. Key words: histamine; Escherichia coli; Klebsiella pneumonia; molecular identification; scombroid; Staphylococcus xylosus