16 FISHERY INDUSTRIES OF THE UNITED STATES. 



freezing tank holding the brine and provided with a propeller (or 

 agitator) and guide plates with sluices for circulating the brine, 

 also a carbon-dioxide refrigerating unit; metal baskets for holding 

 the fish in the brine and galvanized-kon ice cans and wash tank 

 complete the equipment. 



Among the advantages claimed for the brine-freezing method, 

 mention may be made of the following: (1) Fish can be frozen 

 much more quickly — in one-tenth of the time or less — than in air 

 freezing; (2) brine-frozen fish retain the flavor, appearance, and 

 other qualities of fresh fish; (3) in slow air freezing the tissues are 

 partially broken down through the formation of large ice crystals, 

 while in rapid freezing the ice crv^stals formed are so small as not to 

 disrupt the muscle fibers; (4) tliere is no loss of weight in freezing 

 through evaporation; (5) the equipment takes up little space, with- 

 out the necessity for a special freezing room, and is adaptable for 

 use on fishing vessels; and (6) there is no tendency for the brine to 

 penetrate the fish or for its juices to enter and weaken the brine. 



As the Bureau has not conducted exhaustive experiments in the 

 brine freezing of fish it is not prepared to express an opinion with 

 regard to the value of the method or as to its probable place in the 

 industry. The Bureau's Fishery Products Laboratory in Washington 

 is equipped for conducting proper investigations in air and brine 

 freezing to determine the relative merits and defects of the two 

 methods. It is desirous of doing this investigative work as soon 

 as adequate provision can be made therefor. 



INVESTIGATIONS IN CANNING FISHERY PRODUCTS IN SOUTHERN 



CALIFORNIA. 



For years the Bureau has been impressed with the need for render- 

 ing those engaged in the preservation of fish by canning a larger 

 measure of service, work which promised to make larger supplies of 

 wholesome protein food available to the consumer and to reduce 

 the cost of that which was being produced. In the summer of 

 1918 it concluded to initiate such investigations on the coast of 

 southern California and to equip a small plant for the purpose. 

 The immediate object of the work was to develop suitable methods 

 for canning some of the neglected or little-used fishes occurring in 

 abundance in that region and to aid the packers in solving their 

 problems and difficulties. After a study of the principal fishing 

 centers it was decided to start the work at San Pedro, where suit- 

 able quarters for housing the equipment were obtained, the necessary 

 equipment provided, and the work begun about May 1, 1919. 



A study of canning methods in commercial practice revealed 

 wide differences in the processes used. For example, it was found 

 that the time j>eriod and temperature of retorting varied in the 

 different plants. Some used compressed air in the retort when 

 cooling; others did not. Some employed superheated steam exhaust 

 boxes; others no exhaust at all. In some instances large driers of 

 considerable length, equipped with traveling chain-belt conveyors, 

 high-power fans, and an elaborate air-distribution system, were in 

 operation; in others short driers, making use of high temperatures, 

 were employed. One canner holds his pack for a period for ageing; 

 another ships the goods as soon as they are put up. The practices 



