Dosimetry validation via EGS5 Monte Carlo simulation, microbial inactivation kinetics, and quality preservation of frozen sliced squid (Loligo spp.) under 10 MeV electron beam irradiation.

High-energy (10 MeV) electron beam (e-beam) irradiation was investigated as a non-thermal intervention for vacuum-packaged frozen sliced squid (Loligo spp.). Absorbed doses ranged from 1 to 5 kGy, with storage at -18 °C for eight weeks. A core challenge was dosimetry mapping within deep-frozen bulk geometries, since standard B3 thin-film dosimeters lose chemical validity below their glass transition temperature. This was addressed using the Electron Gamma Shower version 5 (EGS5) Monte Carlo code. A dual-beam configuration achieved a Dose Uniformity Ratio (DUR) of 1.18, confirmed via B3 dosimetry in a density-matched phantom, with agreement within 1.7%. Sensitivity analysis showed a 10% fluctuation in phantom density did not raise the DUR beyond 1.28, confirming robustness against packaging variation. Using a high-bioburden challenge model with an initial Total Viable Count (TVC) of 6.8 log CFU/g, the 2 kGy treatment reduced TVC to 2.6 log CFU/g, a 4.2-log reduction, remaining below the 6.0 log CFU/g threshold throughout storage. Lipid oxidation, tracked via Peroxide Value (PV) and Thiobarbituric Acid Reactive Substances (TBARS), followed zero-order kinetics; the 2 kGy treatment yielded a final TBARS concentration of 0.68 mg MDA/kg, below the 1.0 mg MDA/kg sensory rejection threshold. Total color difference (ΔE*) and Warner-Bratzler shear force changes remained within commercially acceptable limits. A discriminative Triangle Test (ISO 4120:2021) detected no statistically significant organoleptic difference, though post-hoc power analysis indicated limited power for strict equivalence. These results support 2 kGy dual-beam e-beam processing as a technologically sound, quantitatively validated intervention for frozen cephalopod safety and quality assurance.