Modelling and Optimization of Gamma Irradiation Parameters in Mushroom Storage Using Central Composite Design (CCD)

The present study aimed to optimize post-harvest treatment parameters for microbial reduction and shelf-life extension of Agaricus bisporus using Central Composite Design (CCD). Fresh mushroom samples were treated with varying levels of gamma irradiation, storage time, and temperature, each tested at five coded levels. Unlike traditional one-factor-at-a-time (OFAT) methods, CCD allowed evaluation of interaction and quadratic effects, providing a more robust statistical framework for identifying optimal preservation conditions. Analysis of variance (ANOVA) indicated that storage time and temperature significantly affected microbial reduction (p < 0.05), while gamma irradiation exhibited interactive effects with these variables. The optimized conditions identified were moderate gamma irradiation (1.5–2.0 kGy), storage at 4–6 °C, and controlled storage duration to minimize microbial load while maintaining product quality. The model demonstrated acceptable fit (R² = 0.7999), though a negative predicted R² suggested limited extrapolation capacity. Findings support that integrating CCD with OFAT effectively enhances parameter optimization, contributing to safer and extended post-harvest storage of Agaricus bisporus. This study offers a scientifically validated approach for commercial mushroom preservation through statistically optimized post-harvest treatments.