Seafood is a highly sensitive and perishable product. It presents major challenges in handling and maintenance of optimal conditions during processing and distribution. The current cold chain which has been established over the years does not effectively meet the requirements of today’s automated processing and much broader distribution. Deepchilling (rapid cooling to and maintenance of subzero temperature) seafood can optimize the cold chain, offering significant advantages over traditional methods such as RSW or flake ice.
Studies have been conducted at various stages of the cold chain (harvesting, processing to distribution) using different species of fish such as farmed salmon, trout, cobia and yellowtail. The tests analyzed cooling rates, bacterial growth, texture after maturing and freshness and evaluated the impact on the yield, shelf life, and quality of the fish.
When salmon and yellowtail are harvested before being gutted, bacteria are quickly developing inside of the fish. Deepchilling fish immediately upon harvest minimizes bacteria growth and maintains freshness from the beginning, so fish are kept safe with an extended shelf-life of up to 5 days. Salmon, once gutted, are normally stored overnight or extra days before filleting and pin-boning. This is a critical period where bacteria growth shall be controlled, and firm texture must be maintained to prevent gaping. To go through the filleting machine efficiently, a deepchilling process shall be arranged, through which fish are kept at optimal subzero temperature and firmness. This reduces fat accumulation on the knife, allowing better operation with cleaner cuts and less gaping. As a result, the quality of fillets is significantly higher and more filleting yield can be achieved.
Yellowtail are very sensitive fish, requiring fast processing time to maintain the highest quality. Often shipped overseas, yellowtail requires extreme quality control, keeping the freshness at peak condition. Deepchilling maintains yellowtail’s prime condition even during filleting, packaging, and overseas shipping. With the extremely high cooling rate and ability to consistently maintain subzero temperature, Deepchilling enables sashimi quality fish and allows distribution from as far as Japan to North America. Similarly, the deepchilling process provides an efficient method for rapid chilling of farmed cobia from a typical tropical temperature down to 0°C and reducing the rate of bacteria growth and spoilage.
The results have shown significant improvement in both quality, shelf life and yield. Deepchilling can provide a sub-zero cold chain and is a proven method in keeping fish at optimal temperatures, controls bacteria growth, freshness and extends shelf-life up to 5 days.