mortis. An additional process called "bleeding" of spiked fish would delay the breeding of microbes that cause deterioration, and would thus yield a higher level of freshness in the fish for a longer time compared with when a fish dies naturally. Although spiking is generally recognized as effective, it is time-consuming and thus expensive because it must be done fish by fish, and consequently is generally not carried out on fish other than expensive and/or relatively large-scale fish. To maintain freshness as high as that achieved using the spiking procedure, the time in which a fish moves violently until it dies must be as short as possible. Slurry ice with small particle diameter and high fluidity (i.e., sherbet-like ice) is suitable for this purpose due to its high contact frequency and high rate of heat exchange with the fish for rapid chilling. If such slurry ice is used in the marine product industry, the freshness of fish can be kept high by preventing deterioration of the fish. Utilization of slurry ice for freshness produces a competitive advantage in this industry domestically as well as internationally.In this paper, the development of a compact icemaker that produces slurry ice from seawater stably and continuously and that can be easily installed on a fishing vessel is described along with its design policy and the effects of such ice in maintaining freshness of marine products.
Development backgroundDevelopment of an icemaker that produces ice to maintain the freshness of fish is expected to yield higher fish prices, specifically the development of a compact icemaker made in Japan to rapidly produce optimal ice onboard a fishing vessel. As early as the 1980s, the effectiveness of slurry
IntroductionIn 1965, the Resources Council of the Science and Technology Agency in Japan announced the need for modernization of the transport and distribution system of food (aka cold chain recommendations) to systematically improve the eating habits of Japanese people by ensuring healthy and desirable dietary modification. Thereafter, quality control of food in the distribution system was enforced. In this quality control, broad distribution and long-term preservation have been achieved by minimizing the deterioration of perishables via temperature control during refrigeration or freezing. The consumerʼs need for food safety and security in the cold chain system has been attained by technological advances as a result of having improved infrastructure for sufficient traceability of transportation routes and their environmental conditions, and also by implementation of severe quality control procedures such as HACCP Term 1 and the food safety management system of ISO22000. Furthermore, fresh fish will surely have a higher market value. Suitable processing from the time that fish are caught until consumption is critical for maintaining such freshness. To prevent degradation and to maintain quality of the fish, crushed ice and/or the plate ice made from fresh water is generally loaded onto fishing vessels upon their ...