Atlantic cod has been one of the most important commercial species for the North Atlantic fisheries. Effective cod preservation is an important concern for all stakeholders from the fishermen, producers, and consumers.
A common method of seafood preservation is flake ice. Though known for having good cooling capacity, flake ice is not as efficient cooling medium as DeepChill® slurry ice, doesn’t maintain its freshness and quality of the fish.
DeepChill® cools cod 3-4 times faster than flake ice; and keeps it just above freezing point. The soft slush suspends and protects delicate cod from cuts, bruising, freezer burn, and tissue degradation.
This report reviews various studies and presents the results of DeepChilling versus traditional icing methods on cod, the impact on quality and shelf life, and its implications for the industry.
DeepChiling & cod quality
An Icelandic study on the use of superchilling (AKA DeepChilling) cod and its effect on quality aspects of the fish investigated 4 conditions: (A) superchilled (at -1°C) on-board and in storage, (B) traditional ice on-board and superchilled in storage, (C) superchilled on-board and chilled in storage (at 0°C), and (D) traditionally iced on-board and chilled in storage2.
Researchers analyzed various sensory outcome attributes of the cod, such as odour, appearance, flavour, and texture. In addition to reporting on temperature, they looked at the cod’s chemical and microbial profiles (TVBN).
Test conditions (A) and (B) had both a significantly extended freshness period (2 – 4 days) and shelf life (2 – 3 days) as compared to the conditions where traditional chilled storage was applied.
In conclusion, superchilled storage of cod was crucial in extending its shelf life and quality; and on-board superchillng was integral in slowing decomposition of muscle proteins and protecting the fish against bacterial deterioration.
Other studies on DeepChilling effects on quality aspects of cod confirm similar benefits as summarized here3 :
Better chemical analysis
Scored higher on microbial, and chemical analyses.
Improved Sensory score
Improved flavour, texture, odour, and appearance (e.g. colour and shape).
Lower drip loss
lower drip loss in super chilled than in the ice chilled or the 21°C frozen cod.
Eased muscle rigor mortis contractions and lowered gaping.
Source2: Eliasson, Saemunder, et al. “The effects of superchilling on shelf-life and quality indicators of whole Atlantic cod and fillets.” LWT 100 (2019): 426 – 434.
Source3: Duun, A.S., Rustad, T., 2007. Quality changes during superchilled storage of cod (Gadus morhua) fillets. Food Chemistry 105 (3), 1067–1107.