Salt-Controlled Under-Cooling Method to Delay Fish Rigor Mortis
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Solution Overview
Problem
Current methods for cooling and processing fish after slaughter often result in quality issues such as bacterial contamination, ice damage, and inefficient processing due to the formation of ice shells and uneven temperature distribution.
Innovation Solution
A method and device using a salt- and temperature-controlled solution to under-cool whole fish directly after slaughter, preventing ice shell formation and ensuring uniform cooling by maintaining continuous movement of the fish and a solution-to-fish ratio of at least 50%, thereby delaying rigor mortis and prolonging the rigor phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fish is cooled using ice in Styrofoam boxes, then the fish is cooled down, but the ice damages the surface of the fish and creates environmental disposal issues
Solution Approach 1:
A saline solution acts as an intermediary cooling medium between the fish and direct ice contact. The solution transfers heat away from the fish while preventing ice formation on the fish surface, eliminating surface damage and reducing environmental disposal issues associated with melting ice
Solution Approach 2:
The invention changes the physical state parameters by maintaining the cooling medium as a liquid saline solution rather than allowing it to freeze into ice. By controlling the salt concentration and temperature to stay above the freezing point, the system achieves continuous liquid-phase cooling without ice shell formation
2Temperature
If fish is cooled using slurry ice or saline solution to undercooled state, then the fish can be processed in rigor, but ice shell forms on the surface and temperature distribution becomes uneven
Solution Approach 1:
The system dynamically adjusts the cooling process by continuously circulating the saline solution and controlling temperature gradients. The solution is pumped through the system at controlled rates to ensure uniform heat transfer throughout the fish batch, preventing localized ice shell formation
Solution Approach 2:
Temperature sensors monitor the cooling process in real-time, providing feedback to the control system. This allows continuous adjustment of cooling intensity and solution circulation to maintain uniform temperature distribution and prevent ice shell formation while achieving the desired undercooled state
3Reliability
If fish is frozen to reduce bacterial contamination, then bacterial growth is reduced, but the fish cannot be provided as fresh unfrozen fish
Solution Approach 1:
The invention changes the temperature parameters to achieve undercooling below the freezing point without actual freezing. By maintaining temperatures in the range of -1°C to -4°C through controlled saline solution cooling, the system achieves bacterial inhibition typically associated with freezing while keeping the fish in a fresh, unfrozen state suitable for high-quality markets
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in better quality fish products with reduced bacterial contamination, improved processing efficiency, and extended shelf life, as the fish can be stored and processed in an unfrozen, ice-free environment.
Implementation Method 1
bringing the fish to an under-cooled state in a salt- and temperature-controlled solution
Implementation Method 2
providing substantially continuous movement of the fish in the solution during the step of bringing the fish to an under-cooled state
Data Source
AI summary
A method and an apparatus for bringing fish to an under-cooled state by a sub-chilling process before processing, which prolongs rigor and allows processing of the fish in rigor providing better quality fish products.