Computer simulation on onboard chilling and freezing of albacore tuna

We extended the application of a commercial finite-element computer program package, PDEase, to the simulation of chilling and freezing of albacore tuna. Tuna was described as an infinite elliptical cylinder, where nonuniform boundary conditions present complications in computer simulation. Equations were developed to define the elliptical boundary. Temperature-dependent thermal properties and time-dependent ambient temperature conditions were used. Onboard experiments were conducted to measure the core temperature of individual tuna in slush ice tanks and in air-blast and brine-spray freezing systems. Measured time-temperature profiles were compared with those of the simulation. Predicted chilling and freezing curves agreed with experiments +/-3 to 6%. This program enables testing of important fish industry operation strategies.