Post-mortem cold shock physiology: A novel mechanism validating ancient sashimi practice, extending shelf-life via chemical and cellular stabilization

Debate persists on how moderate chilling affects sashimi palatability. This study reinterprets its impact through the framework of post-mortem cold shock physiology in fish fillets. Red sea bream ( Pagrus major ) sashimi, subjected to controlled cold shock (liquid-induced, ∼ 0 °C, 10 ∼ 40 min), exhibited profound physiological shifts during 120 h of storage. Cold shock markedly suppressed metabolic activity, as indicated by reduced k-value and Ca 2+ -ATPase activity. The suppression attenuated spoilage pathways: lipid oxidation (declines in PV and TBARS), protein degradation (reduced TCA-soluble peptides and TVB-N), and microstructure deterioration (stabilized surface hydrophobicity, sulfhydryl groups, and limited protein carbonyls). Microbial growth (TBC and PC) was significantly inhibited, leading to drastically reduced biogenic amine accumulation, particularly histamine, which remained at 3.7 mg/kg versus 36.9 mg/kg in controls after storage. Consequently, sensory acceptance was significantly enhanced, and the acceptable period was extended from < 48 h to beyond 120 h. By elucidating the physiological mechanism underlying cold shock, this work provides a scientific foundation for an ancient culinary practice, bridging millennia of culinary wisdom with cutting-edge food science. • Using modern concept of cold shock response reveals traditional chilling practice • Cold shock affects the comprehensive metabolic response in slaughtered fish cells • Cold shock reduces microbial counts and biogenic amine levels in sashimi • Cold shock prolongs sensory acceptance period of sashimi by over 2.5 times