This study investigated the effect of sub-chilling whole gutted salmon and sub-chilled storage at −1 °C in modified-atmosphere packaging in two recyclable mono-material trays (CPET, HDPE). Quality parameters were measured, including water-holding properties, salt content, color, texture, lipid oxidation, and sensory and microbiological shelf life. The oxygen transmission rate was measured for the packages. Compared to traditional fish storage on ice, sub-chilling gave a 0.4% weight gain, better water-holding capacity, and higher salt content. The sub-chilled fish gave a significantly better sensory quality and microbiological shelf life of up to 49 days. Photobacterium was the dominating bacteria during storage. Salmon packaged in CPET trays had a higher drip loss than HDPE trays, but a lower rate of lipid oxidation (1-penten-3-ol). Our results showed the feasibility of significantly extending shelf life with sub-chilling, removing the need for ice. Moreover, using recyclable trays for packaging contributes to a circular economy without compromising food quality.

This study evaluated the sub-chilling of whole gutted Atlantic salmon in refrigerated seawater (RSW) maintained at -1 °C for 7 days, compared to traditional ice storage at 0 °C and RSW storage at -1 °C for 4 days followed by 3 days without ice. After filleting, portioning, and modified atmosphere packaging, the initial RSW-stored fish were continuously stored at -1 °C, while the initial ice-stored fish were stored at refrigerated temperatures at 4 °C. The 7-day RSW storage resulted in a significant weight gain, higher water-holding capacity (WHC), and increased water and salt content. Ice-stored fish had higher calpain activity. After packaging, drip loss was highest for the 4-day RSW-stored fish. The 7-day RSW-stored fish demonstrated consistently better WHC and water content. The CO₂ levels decreased, while O₂ levels increased more rapidly within the package for the RSW-stored fish. There was also a significant extension in the microbiological and sensory shelf life for the RSW-stored fish. Photobacterium was the dominant bacterium in all storage methods. This study highlights the potential to extend salmon shelf life with sub-chilling, significantly reducing ice usage.