Reports

Sub chilling of fish

Published:

17/07/2017

Authors:

Gunnar Þórðarson, Sigurjón Arason, Magnea Karlsdóttir

Supported by:

Technology Development Fund

contact

Gunnar Þórðarson

Regional Manager

gunnar.thordarson@matis.is

Sub chilling of fish

The aim of the project was to utilize the knowledge of supercooling of fish that has been developed in laboratories in recent decades; industrialize the concept and develop methods and equipment to control the cooling. It is important to cool the raw material below the freezing point or just below the temperature at which the first ice crystals form in the fish species in question, fast enough so that large crystals do not form in the muscles and cause cell damage. It is important to control the cooling correctly as well as to maintain a supercooled condition during storage and transport, but fluctuations in temperature can cause quality deterioration. The results of research show that ice-free transport and storage of super-chilled fish is a realistic solution that reduces the cost of fishing and processing as well as reducing the cost of transport and significantly reducing the footprint of fresh fish production. Fresh salmon has been transported ice-free but super-chilled for shorter and longer distances and stored for a week before processing with excellent results. In connection with the project, supercooling has been used on a large scale in Sauðárkrókur, where the trawler Málmey SK 1 has landed over 15 thousand tonnes in the past two years of supercooled catch and thus not used ice on board or for storage for production in fish processing.

The project objective was to utilize knowledge of sub chilling of fish developed in laboratories for the past decades; and to industrialize the concept and to develop methods and means for centralizing the process. The control of the chilling process is important, to chill raw material sufficiently without freeze out more than 20% of its water and without developing large ice crystals in the muscles. It is also important to keep storage temperature under control and stable and for the same reason temperature fluctuation can cause growth of ice crystals in the muscle. Based on results obtained in present project it can be concluded that sub chilling provides opportunities to use ice-free value chain for fresh fish, lowering cost of production, logistic and considerably the carbon footprint for the final products. Fresh salmon without any external refrigerant (ice) has been transported for long distance, by trucks and airplanes, and stored for long time with acceptable results. The trawler used in this project has landed over 15 thousand tonnes of sub chilled fish for the last two years without using any ice for chilling and storage. The fish is stored in the fish plant and processed without using any ice preservation.

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Reports

Sub-chilling of salmon

Published:

01/12/2015

Authors:

Gunnar Thordarson, Magnea Karlsdottir, Roger Pedersen, Magnus Johannsson, Albert Hognason

Supported by:

Norwegian Research Council

contact

Gunnar Þórðarson

Regional Manager

gunnar.thordarson@matis.is

Sub-chilling of salmon

The aim of the project was to increase the quality of fresh salmon production, by improving the cooling chain during production and transport. By using supercooling methods, salmon producers will be able to reduce their production costs due to lower transport costs and at the same time improve the quality of production. The salmon was cooled to -1.5 ° C which increased the lifespan and quality of the product. In addition to improving production during slaughter, gutting and packaging, supercooling can also create opportunities for further processing; filleting, smoking, chopping, etc. to improve their production through increased utilization and value along with happier customers. Among other things, supercooling makes it possible to transport the refrigerant into the fish flesh instead of using ice for transport. The project compared the cooling chain of super-chilled salmon with conventional. The former was transported without ice but the traditional one with ice, for further processing in Finland and Norway. Such a comparison was also made between super-chilled and traditional salmon that was transported to Iceland via Oslo on the one hand and to Tokyo via Oslo on the other. The results give rise to optimism about the use of supercooling in the salmon transport chain, both to reduce transport costs and to ensure product quality.

The ultimate goals of the project was to increase quality of fresh salmon products, provide a more secure cold chain of fresh product, and lower production and logistic costs. Having the fish in a sub-chilled state throughout the production, will give Grieg Seafood several quality advantage including firmer raw material and lower bacteria and enzyme activity in the fresh fish. Fish was packed in a sub-chilled state of -1.5 ° C, hence extending shelf-life and quality. This will have several advantages for the primary producer, resulting in products with higher yield and more value, and in products of higher quality for their customer of secondary processing. Secondary processors will have better control of the product logistic and extended time for selling fresh product with longer shelf-life. Using the sub-chilling method, no ice will be needed during logistic, saving enormous transportation costs, especially in airfreight. Comparison between the cold-chain of sub-chilled and traditional produced salmon was executed in this project, with the former transported without additional ice. The salmon was trucked from Simanes to a secondary processors in Finland and Denmark with excellent result. The two groups were also flown to Iceland, via Oslo, and also to Tokyo via truck to Oslo. The result of this comparisons demonstrates that the sub-chilling method could be used to minimize transportation cost and secure the product quality during logistics.

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