302 PRESERVATION METHODS 



mechanical refrigeration. It may contain space for freezing and, in some 

 cases, glazing or packaging products; receiving and delivering products; 

 refrigeration and other machinery; and offices, lockers, etc. 



Today some refrigerated warehouses, particularly those located in the 

 major fishing ports, are built especially for fisheries applications. But in 

 most cases refrigerated warehouses are the general custodians of many 

 different types of packaged frozen foods, all of which vary considerably 

 in storage and handling requirements. The trend to automation has re- 

 sulted in modern, low-story palletized warehouses arranged so that the 

 products can be taken off rapidly or put on refrigerated trucks or rail- 

 way cars servicing the storage facility. There is a definite tendency to 

 limit activities to the storing of frozen foods, thereby leaving to others 

 the specialized treatments of glazing or packaging or even, in some cases, 

 freezing. 



Temperatures of 0°F or lower generally are used in the newer cold- 

 storage warehouses and in many of the older ones for the storage of frozen 

 fish. The trend in recent years has been to construct refrigerated ware- 

 houses that will maintain temperatures of — 10°F. In some warehouses, 

 temperatures as low as — 20°F are being used for storing frozen fish. 



Many of the older refrigerated warehouses that are used for storing 

 frozen fish are of multistory construction. Bare pipe-coil evaporators 

 generally are used in these installations. Brine or flooded ammonia sys- 

 tems are used to provide the refrigeration effect. The refrigeration ma- 

 chinery is comprised of large slow-speed ammonia compressors. These 

 warehouses were designed for nonpalletized operation, but conversion to 

 palletized operation has been accomplished by using light-weight me- 

 chanical lift trucks. This conversion has reduced the labor necessary for 

 product handling by 50 per cent. In the last decade, many new refriger- 

 ated warehouses have been constructed for storing fish and other foods. 

 These warehouses are one or two stories high and are palletized through- 

 out. Location and design of the loading facilities in these plants permit 

 mechanical unloading of frozen fish from refrigerated railway cars or 

 trucks directly into the cold-storage rooms. A modern warehouse located 

 on the eastern seaboard is situated so that frozen fish can be unloaded 

 from refrigerated vessels into the frozen-storage area. Air-operated freezer 

 doors and hydraulic ramps for unloading trucks facilitate handling of 

 products. 



Cold-storage plants which handle whole or dressed fish usually contain 

 facilities for washing, glazing, packaging, and storing the fish. Halibut 

 and salmon are usually washed with fresh water, then laid out to freeze 

 on the shelves of a sharp freezer similar to those described previously. 

 After freezing, the fish may be placed into a wire pallet box and carried 



