Research – Survival and Histamine Production by Histamine-Forming Bacteria Exposed to Low Doses of Gamma Irradiation



Histamine poisoning occurs when fish containing high amount of histamine are consumed. Because histamine is thermally stable, control of histamine-forming bacteria in seafood is an appropriate strategy for preventing the formation of histamine. One prevention method is the use of gamma irradiation on the histamine formers. To understand the effect of gamma irradiation on the histamine-forming bacteria, laboratory isolates of the prolific histamine formers Morganella morganii, Klebsiella variicola, and Proteus vulgaris were exposed to various doses of gamma radiation in nutrient broth and tuna muscle spiked with histamine formers. None of the test bacteria survived in tuna muscle irradiated at 2.0 kGy. K. variicola was highly sensitive to gamma irradiation and was eliminated at a dose of 1.5 kGy. Histamine production also was reduced significantly as the radiation dose increased. These results suggest that gamma irradiation can effectively eliminate histamine-forming bacteria and reduce the threat of histamine poisoning from seafood.

  • Histamine-forming bacteria are highly susceptible to low levels of gamma irradiation.
  • Prolific histamine formers in tuna meat were eliminated by irradiation at 2.0 kGy.
  • Irradiation at 1.5 kGy reduced the level of histamine formers in tuna meat by 4 to 5 log CFU.
  • Histamine formation in tuna meat can be controlled by low levels of gamma irradiation.

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