Subchilling of brown trout (Salmo trutta) with refrigerated seawater and subsequent effects on its quality and shelf life.

Brown trout (Salmo trutta) is an emerging species for aquaculture in freshwater systems in Norway sold at the high-end fresh markets in Europe. Therefore, efficient temperature management is crucial to prevent fish spoilage during transportation and storage. This study investigated the impact of sub-chilling on the quality and shelf life of whole gutted brown trout, including temperature abuse during transport. Sub-chilling in refrigerated seawater (RSW) was compared with the traditional chilling method using ice. Water holding capacity (WHC), weight changes, colour, texture, quality index method, gaping, microbiological analyses, and enzyme activities were assessed over an 18-day storage period. Results showed an initial increase in WHC in fish stored in RSW, although this effect diminished over time. Weight gain was observed during RSW storage, followed by drip loss upon transfer to ice storage. Texture analysis showed fillet hardening during storage across all groups. Enzyme activity increased temporarily post-temperature abuse but did not significantly differ between groups, indicating sub-chilling's minimal impact on enzymatic reactions. Microbial analysis showed minimal differences among the groups, with the microbiota dominated by Pseudomonas spp. on day 11. Overall, sub-chilling in RSW showed potential storage without ice, without significantly compromising quality or shelf life. These findings suggest that sub-chilling techniques could reduce reliance on ice during fish transportation and storage, contributing to more sustainable practices in the aquaculture industry.