Effect of Low Dose Gamma Irradiation and Refrigeration on the Chemical and Microbial Quality of Shrimp (Penaeus monodon)

The present investigation is aimed at studying the effect of gamma irradiation (1, 3 and 5 kGy) and subsequent storage at refrigeration temperature (4°C) on the chemical, microbial quality and extended shelf-life of shrimp (Penaeus monodon). The total volatile base nitrogen (TVB-N) and trimethyl amine nitrogen values (TMA-N) of the irradiated shrimp samples significantly decreased in comparison with the control (non-irradiated) stored at 4°C. The thiobarbituric acid values for the irradiated shrimp was significantly lower than of the non-irradiated samples stored at 4°C (p<0.05). The pH value of the shrimp was affected significantly by both, irradiation dose and storage temperature (p<0.05). The total microbial load for the non-irradiated shrimp samples was higher than those of irradiated samples at 4°C temperature. The results revealed that the combination of low dose gamma irradiation and refrigeration storage resulted in overall reductions of microbial loads and stabilized the biochemical characteristics of shrimp.