DESIGN AND TESTING OF A PROTOTYPE OHMIC THAWING UNIT

A significant proportion of seafood is imported into the U.S. in the f orm of frozen blocks. Before these can be further processed, they must be thawed, traditionally by immersion in warm water. This requires la rge amounts of fresh water, that become wastewater. It is also slow an d potentially compromises the quality of the food. Ohmic heating can b e used to thaw blocks. The major concern of this method is 'runaway he ating.' This occurs because electrical conductivity of frozen food is about two orders of magnitude lower than that of thawed food. The purp ose of this study was to design, build and test an automated, computer controlled prototype ohmic thawing unit. Control circuitry was design ed and custom built. Performance was tested with shrimp blocks. (C) 19 98 Elsevier Science B.V.