IceBits ehf’s Ingvar Nielsson discusses curing offal at North Atlantic fishing ports.
In North-Atlantic fishing ports, offal from filleting demersal species (cod, haddock and saithe) is cured and exported to Nigeria.
Ambient air is heated to 27°C and forced through stacks of grids loaded with the offal. At higher temperatures, broiling takes place in the product and reduces the quality. Air at atmospheric conditions prevailing in Iceland assumes low relative humidities when heated to 27°C. Further south ambient temperatures exceed 20°C, and the heating results in much higher relative humidities - and slower curing.
Ambient temperatures above 20°C are usually associated with high relative humidities. Air for curing must then be recirculated and dehumidified through refrigeration. Air returning from the goods enters the package through the cooler; there it is dehumidified, cooled and finally reheated in the heater. Excess heat from electric motors driving the compressor and fans is rejected through an external air cooled condenser. Non-condensable odour contaminated gases are purged, thus rendering the plant odour free.
Work on the shop floor still takes place in a rather outdated manner. Wet raw material is arranged manually on grids, which are moved along on hand operated fork lifts. A plant to cure two lots of 6,000kg of wet material in one week needs 800-1,000 grids for 'pre-drying', half of which is under load in the curing chambers while the other half is being loaded with the next lot. Following the 'pre-drying', the material is transferred to tubs for 'after-drying' and 'equalisation' and left in adjacent rooms for the remainder of the week before being pressed and bagged.
Ingvar says that the procedure is cumbersome and labour intensive. The grids and tubs must be cleaned and maintained, and replaced when damaged beyond repair. He says that a state-of-the-art curing plant for the said throughput would consist spiral conveyors for 'pre-drying' and flat belt conveyors for 'after-drying' and 'equalisation'. Refrigerated recirculated air or heated ambient air would pass through the goods in counter flow - vertically down in the spirals and vertically up through the flat belts. The plant would operate semi-automatically.
