11/08/2026
The findings from the MDPI study demonstrate that environmental conditions at harvest—specifically seawater temperature—directly govern post-mortem muscle breakdown in Mediterranean-farmed fish (Sparus aurata, Dicentrarchus labrax, and Pagrus major), dictating shelf life and fillet quality. Counterintuitively, peak proteolytic activity across key enzymes (calpain, collagenase, cathepsin B, and cathepsin L) occurs not during extreme winter cold or summer heat, but during transitional moderate-temperature seasons like spring and mid-autumn, rendering fish harvested in these windows particularly vulnerable to accelerated flesh softening and muscle gaping.
To mitigate this seasonal risk, commercial aquaculture operations and quality control teams must adapt their post-harvest logistics around a distinct two-phase enzymatic degradation timeline. The early phase (Days 0 to 5) is driven by calpain and collagenase attacking structural proteins and connective tissue, which requires immediate post-slaughter sub-zero cooling via optimized ice-slurry systems and pre-harvest stress reduction to suppress early loss of firmness. In contrast, late-phase degradation (Days 5 to 13) is governed by lysosomal cathepsins released as cell membranes rupture, necessitating targeted preservation technologies—such as sub-chilling (-1°C to -2°C), modified atmosphere packaging (MAP), or natural enzymatic inhibitors—for products intended for extended retail display or long-distance cold chains. Because baseline enzymatic rates and responses vary significantly across S. aurata, D. labrax, and P. major, producers must replace "one-size-fits-all" processing with species-specific harvest calendars, chilling ramps, and shelf-life expectations, prioritizing moderate-temperature harvests for rapid local distribution or secondary processing where soft texture is less critical.
Source: https://www.mdpi.com/2673-9496/6/1/2
