Gamma radiation effect on quality changes in vacuum-packed squid (Illex argentinus) mantle rings during refrigerated (4-5 °C) storage

The effect of gamma radiation (0, 1.8, 3.3 and 5.8 kGy) on microbiological, chemical and colour characteristics of vacuum-packed squid (Illex argentinus) mantle rings was studied. Total viable counts; psychrotrophic bacteria counts, Escherichia Coli, Staphylococcus aureus and Clostridium perfringens; total volatile basic nitrogen (TVBN) and colour difference were analysed during 29 days of storage at 45 degrees C. Higher doses of gamma radiation significantly reduced Total Viable, phychrotrophic counts and TVBN production (P < 0.05) in a dose-dependent way, delaying squid spoilage. Colour difference of non-irradiated samples with respect to first day significantly increased while it was constant in radiated samples during 22 days (P < 0.05). Independently from the dose, radiation avoided colour changes of squid rings. Gamma irradiation was effective in delaying deterioration reactions, improving microbiological, chemical and colour quality of vacuum-packed squid rings stored at 45 degrees C.