No abstract

Scombroid food poisoning is caused by the consumption of histaminecontaining foods. Since histamine is thermally stable, controlling histamineforming bacteria in seafood is an effective technique for limiting histamine generation. The aim of this study was to investigate the induced effects of gamma radiation on the development of histamine-forming bacteria, specifically Pantoea agglumerance, in both mackerel flesh and tryptone soya broth. Klebsiella pneumoniae, Pseudomonas fluoresense, Pantoea agglumerance, and Bacillus sp. are histamine-forming bacteria were cultured in tryptone soy broth and exposed to gamma irradiation at doses of 0.25-5 kGy. In the meantime, mackerel meat was injected with the histamine-forming bacteria and then gamma-irradiated at 0.25-5.0 kGy. K. pneumonia and Pseudomonas fluoresense were particularly susceptible to gamma irradiation, and at 1.5 kGy, they were completely destroyed. Pantoea agglumerance and Bacillus sp. were found to be more resistant, with total inactivation at 3.0 and 5.0 kGy, respectively. The D 10values to inactivate 90% of the bacterial populations in tryptone soya broth and inoculated mackerel ranged from 0.13 to 1.03 kGy and 0.14 to 1.12 kGy, respectively, depending on the kind of bacteria. These findings imply that gamma irradiation can efficiently eradicate histamine-forming bacteria, lowering the risk of histamine poisoning from seafood. However, because modest doses of irradiation are ineffective in decreasing Bacillus sp, the early counts of Bacillus sp in fish samples should be closely monitored.

The effect of different doses of gamma radiation viz. 15, 20, 25 and 30 kGy on the chemical and functional characteristics of the amniotic membrane was studied. The change in the chemical structure of amniotic membranes at high doses of gamma irradiation was evaluated by means of Infrared (IR) Spectroscopy. The degradation of amnion on irradiation with gamma rays could produce a relative variation in IR absorption troughs. This kind of variation was absent in the samples irradiated to doses of 15, 20, 25 and 30 kGy indicating no qualitative change in the material property of amnion. No significant differences in the water absorption capacity and water vapour transmission rate of amniotic membranes irradiated to different doses were observed. The impact of irradiation doses on antibacterial effect of human amniotic membrane in vitro, showed the inhibitory effect of amniotic membrane on three standard bacterial strainsImpermeability of the amniotic membranes to different microorganisms was also not affected at high doses of gamma radiation. Gamma irradiation at doses of 15-30 kGy did not evoke undesirable changes in the functional properties of the amniotic membrane.