Effects of 60Co γ-ray with different dosage rates and high energy beam on the fresh-keeping of grass carp

The effects of irradiation dosage rate ( the electron beam, high-dose-rate ⁶⁰Co γ-ray irradiation, low-dose-rate ⁶⁰Coγ-ray irradiation and the control, rating in descending order) and vacuum packaging on fresh-keeping of grass carp fillets stored at ( 4 ± 0.5) ℃ were evaluated basing on physicochemical indexes including Total volatile base nitrogen ( TVB-N) , p H and K value, microbiological indicator ( Total viable counts ( TVC) ) and sensory evaluation. The results showed that the p H increased at first, then decreased with the storage time.The growth trend of TVB-N and TVC were slowed down as the increase of the irradiation dosage rate. The samples irradiated by electron beam exceeded the TVB-N ( 20 mg/100 g) and TVC limits ( 5 log10CFU/g) in 27 d and 21 d, respectively, and the sensory evaluation value was 3.01 in 9 d. However, electron beam irradiation had little inhibiting effect on the increase of K value.The grass carp fillets irradiated by high-dose-rate ⁶⁰Co γ-ray reached the limits of TVB-N and TVC in 21 d and 20 d, respectively, and the sensory evaluation value was 3.51 in 9 d.The K value could be well repressed by the irradiation of ⁶⁰Co γ-ray. The study showed that high-dose-rate ⁶⁰Co γ-ray irradiation was the best choice for fresh-keeping of grass carp fillets after comprehensive evaluation.