Superchilling of Fish

The project will address the problems of fluctuation and uncontrolled temperature in fresh fish processing and logistics, from harvesting to market, by developing a technology based on the superchilling concept ready for industrial implementation.

In short terms, superchilling is a method that makes the use of ice redundant in cooling and storing fish by using new technology to cool fish to -1° to -2°C, on the borderline of being frozen, but cooling it beyond what can be achieved with ice.

The water content of fish ranges from 65 to 85%, depending on the species. Superchilling effectively utilises the fish itself as a cooling medium. The temperature can be maintained without the fish being frozen, so ice becomes unnecessary for either storage or transport.

Superchilling retards the onset of rigor mortis and research shows that shrinkage effects become minimal. Fillets become firmer, with less tendency to flake, while rigidity and flexibility are improved to enhance quality and yield, which contribute to easier processing. This applies to de-heading, filleting and skinning, as well as to backbone removal.

What are the advantages?

Extensive research has been carried out into this method, overseen by Matís, with farmed salmon tracked from slaughter, through transport and production processes, to the consumer. Research has also included comparisons of the cold chains in handling both superchilled and conventionally produced salmon.

The former is transported without ice and conventionally produced fish in ice, for further processing in Finland and Norway. Similar comparative studies were carried out on superchilled and conventional salmon shipments to Iceland via Oslo and to Tokyo via Oslo.

These studies have confirmed that superchilled salmon holds its water content better throughout the production and storage processes, and it has a better culinary yield, such as when poached. The qualities and the firmness of the fish remain for longer, maintaining quality more effectively through production.

Microbiological analysis has also confirmed that the fish stays fresher for longer than conventionally chilled fish, also confirming that superchilling can extend the shelf life of the finished product by as much as a week.

Improved handling

With ice no longer a part of cooling, storage and transport, it’s clear that we are entering a new era. To begin with, handling becomes less arduous and there are new opportunities for packaging. Until now it has not been though advisable to transport whole salmon iced in tubs, as the ice can damage the fish. But the best quality can be achieved using superchilling.

The extended shelf life ushers in significant changes in transporting fish to markets, opening the way for rationalisation. A longer shelf life means that fish can be transported by sea rather than by air. This represents a saving in transport costs, as well as a substantial reduction in the carbon footprint. Until now, salmon has mainly been transported in single-use packaging, but superchilling means that tubs can be used instead.

Reducing the carbon footprint

Superchilling does not just have economic benefits. This approach demonstrates a significant contribution in environmental terms with a reduced carbon footprint in production and transport.

Approximately 20% of the overall weight in salmon transport is ice. Superchilling makes ice redundant and reduces the strain on much of the transport chain, by air, road or by sea. The extended product shelf life brings in possibilities to ship larger volumes in containers to replace the amount of fresh whitefish exported from Iceland by air.

Production of farmed salmon in Norway, the Faroe Islands and Iceland has in recent years topped the million tonne mark, while the domestic market for these products is estimated to be only around 36,000 tonnes. A million tonnes of salmon are shipped to other markets every year.

In rough terms, we can estimate that in the region of 200,000 tonnes of ice are shipped with this salmon. Approximately 240,000 tonnes of salmon every year are freighted by air to Asia, which means that an estimated 48,000 tonnes of this weight is ice – so a saving equivalent to 1000 Jumbo jet flights could be made.

The second year of the project

The project is at the threshold of finishing the research on superchilling method, to get ready to introduce the idea to the fish industry on a larger scale, as new project with lot of potentials. Next steps will be working on large amount of data and information’s to be translated in knowledge to be ready for marketing a new product “Sub Chilled Fish”.

Project Partners

Project Owner
Grieg Seafood

Project leader
Gunnar Thordarson, Matis