Isolation of bacteria capable of degrading histamine in fermented mackerel(Scomberomorus guttatus)

Histamine, a biogenic amine, can be formed in foods via decarbonizing reactions of histidine and can cause health problems in consumers. Thus, histamine levels in foods, especially fermented seafood, are strictly controlled during harvesting, preserving, processing, and delivery. In this study, fermented mackerel (Scomberomorus guttatus) was collected and used to identify histamine-degrading bacteria. Five strains of bacteria grown in histamine medium were isolated, of which two strains (HF1 and HF2) showed the highest biomass in the 50 ppm histamine-supplied medium. After culturing for 24 hrs, the bacteria showed the highest activities at pH 7.0 and 30°C, and the efficiency of histamine degradation catalyzed by HF1 and HF2 strains was 34% and 31%, respectively. Biochemical characteristics investigation and 16S-rRNA sequencing of the HF1 indicated that the bacterial strain HF1 belonged to Pseudomonas aeruginosa and was identified as Pseudomonas aeruginosa HF1.