Temperature-dependent quality evolution of Atlantic salmon (Salmo salar): Mechanistic insights into physicochemical and microbial dynamics.

Although conventional refrigeration is widely used for Atlantic salmon preservation, rapid quality deterioration limits its shelf life. With increasing consumer demand for fresh-like salmon products, ice-temperature and micro-freezing preservation techniques have gained attention. In this study, Atlantic salmon was stored for 10 days under refrigeration (4.0 °C), ice-temperature storage (-0.5 °C), and micro-freezing storage (-4.0 °C) to systematically evaluate quality evolution, water migration, and microbial community dynamics. The results demonstrated that salmon stored at -0.5 °C exhibited superior quality retention, as indicated by lower increases in Total Viable Counts (11.29%) and reduced expansion of muscle interstitial spaces (10.89%). Low-field nuclear magnetic resonance indicated that -0.5 °C storage stabilized water status by retaining immobilized water and restricting its conversion to free water. Moreover, 16S rDNA sequencing revealed that -0.5 °C effectively inhibited the proliferation of Firmicutes, thus delaying microbial succession and extending the shelf life. Taken together, ice-temperature storage outperformed conventional refrigeration and micro-freezing storage, providing mechanistic insights and a theoretical basis for high-quality preservation of salmon.