REFRIGERATION AND FREEZING OF FISH 353 



penetrates the fish during freezing, storage, and transportation to the cannery. 

 In an experimental study Godsil (1940) found that brine at 20° F (-6.7°C) 

 "pickled" the ilesh of the tuna to a depth of IM inches in 34 days and to an equal 

 depth when the fish were held at 25° F (- 3.9° C) for 27 days. However, the 

 salt leaches out during cooking, preparatory to canning, and is not considered 

 objectionable. 



In 1947 the ship, "Deep Sea," began operating in the Bering Sea. Though 

 virtually a factory fishing vessel it can "quick freeze" 1500 pounds of fillets per 

 hour and has a 0° F (- 17.8° C) storage capacity of 300,000 pounds in 8500 

 cubic feet of refrigerated cargo space in 2 holds, divided by a watertight bulk- 

 head. This vessel cost approximately $500,000, is 140 feet long with a 26.8-foot 

 beam, and has a speed of 12 to 14 knots. The "Deep Sea" has a crew of 32 men 

 who will remain at sea for 2 or 3 months, or until the refrigerated cargo holds are 

 full. 



Another American factory ship, the "Pacific Explorer," took her maiden voyage 

 in 1947 and returned with 2300 tons of frozen tuna. This vessel has 7 cold 

 storage rooms with a combined capacity of 168,152 cubic feet, capable of hold- 

 ing 2350 tons of tuna. Seven freezers, totaling 38,602 cubic feet, are located on 

 the second deck; 3 of these are blast freezers, 2 of which take a charge of 15 to 

 20 tons and the largest, 50 tons. In addition, 4 small air-blast freezers, each having 

 a capacity of about 3 tons, are located on the cannery deck for freezing packaged 

 fish. Facilities are provided for the filleting of fish prior to freezing and for the 

 preparation and canning of crabmeat. Since the "Pacific Explorer" acts as a 

 mother ship, she must provide the other fishing vessels with fuel, water, ice, fish- 

 ing gear, and repair facilities. In addition, accommodations for nearly 80 persons 

 are provided. 



Glazing of Frozen Fish 



Various methods have been practiced to prevent the desiccation, rusting, and 

 loss of flavor to which frozen fish are subject d\aring the period of storage. Wrap- 

 ping with impervious paper, glazing, covering with wax or tallow, and freezing 

 in ice blocks have all been tried. The simplest, cheapest, and most practicable 

 method for whole fish is glazing, and, if properly done, answers all requirements. 



Nature and Purposes of Glazing. If the fish, while frozen, are dipped into cold 

 water and withdrawn into the air of a cold room, the adhering film of water 

 freezes, forming a transparent envelope of clear ice surrounding and adhering 

 firmly to the fish. The ice glaze at once brightens the colors of the fish and 

 prevents all evaporation from the fish as long as it remains intact. It serves to 

 retard rusting, but unless the storage temperature is suflBciently low, cannot alto- 

 gether prevent it because the glaze gradually becomes porous. After glazed fish 

 have been stored for some time, upon close examination it will be found that the 

 ice envelope has many small holes through which the oil comes to the surface of 

 the glaze. 



Methods of Applying the Glaze. It is necessary that certain factors be taken into 

 account for the best glazing. In the first place the glaze should be uniform. For 

 some reason, for which no good explanation is yet forthcoming, if the water is 

 too cold 32° F (0° C), the glaze will be pebbly. The water is usually from 34 to 

 38° F (1.1 to 3.3° C), but may be as warm as 50° F (10° C) and still apply a thin 



