;?or froaen,. cured, etc. tuna products. The production of these items 

 is so small in relation to the value of total processed tuna products 

 that they will not be considered in this chapter. Canning of tuna and 

 tufialike fishes is the one big activity in the tuna'' processing industry. 

 The utilization of byproducts, while relatively smaller in econonic value, 

 is a function related to the canning process, 



CANNING 



The principal types of canned tuna and tunalike fishes produced by 

 tr.e domestic tuna processing industry have been discussed in some detail 

 In the chapter on consumption. There, in the sections on pages 58 to 

 74s considerable detailed data are shown on the type of canned products 

 packed by species, can sizes, etc. 



Shore Plant Operation 



The underlying purpose of this section of the report is to determine 

 just how tuna is handled from the time it is received as fresh or frozen 

 fish until it has been canned and stored for shipment. A consideration 

 of the various steps in the canning process should then reveal whether 

 ariy important engineering improvements might be made to improve efficien- 

 cy of operation and reduce costs. 



In carrying out this survey , each plant canning tuna in the United 

 States was visited and thoroughly inspected. Fish were followed through 

 each step of the canning process, and detailed notes were taken on opera- 

 tions of the equipment at each stage. In addition, superintendents and 

 laanagers were interviewed. The geographical distribution of firms can- 

 ning tuna and tunalike fishes in the United States is shown by States 

 since 1923 in table 73. 



The principal steps in the canning process considered and to be dis- 

 cussed in this report include (1) general arrangenisnt of equipment in 

 tuna plants, (2) conveying tuna to the cannery, (3) thawing of frozen 

 fish, (4) butchering, (5) precooking, (6) cleaning, (7) packing, (8) 

 addition of oil and salt, (9) exhausting and seaming, (10) cleaning and 

 retorting of cans, and (11) labeling, boxing, and storage. 



PLANT ARRANGBENT 



Practically all tuna plants are located adjacent to a dock suitable 

 for unloading fish from a vessel and are provided with rail facilities 

 for delivery of cans and other materials (sometimes including frozen fish), 



284 



