20 COmEECIAL FISHERIES REVTE^ Vol. 13, No. 4 



USE OF FROZEN SALMON FOR CANNING^ 



By Maurice E. Stansby* and John Dcssow** 



INTRODUCTION 



During past years a relatively small portion of canned salmon has been prepared 

 from frozen fisli. Occasionally, during gluts, more fish have sometimes been brought 

 to a cannery than could be handled, and where cold-storage facilities were available, 

 such fish have sometimes been frozen and canned as soon as the glut was over. Such 

 a situation has developed particularly in the Puget Sound area and other areas where 

 cold-storage facilities are available and vrtiere the canneries have only a relatively 

 small capacity. 



In recent years frozen fish have been canned in an increasingly large amount 

 for other reasons. Concerns which do not have canning facilities in areas where 

 salmon are abundant have been buying frozen fish in Alaska or Canada and bringing 

 them to locations where they have such canning facilities. The fish are then thawed 

 and canned. This situation has developed especially in areas where the normal fish 

 runs (salmon or other species) have been unusually low. In order to be able to con- 

 tinue the operations of such canneries, there has been a tendency to look for fish 

 elsewhere. If the distance from the fishing grounds to the cannery is so great that 

 the fish cannot be successfully preserved in ice, the only alternative has been to 

 freeze them. In some instances the frozen fish have been held a considerable num- 

 ber of months before they were thawed and canned. The practice of freezing salmon 

 for later canning has also further been encouraged by an excess of facilities suit- 

 able for handling tuna. The tuna industry in the Pacific Northwest has expanded 

 rapidly in recent years. During several of the past years, when tuna could not be 

 caught in abundance in this area, vessels equipped with refrigeration were avail- 

 able in excess of the needs of the tuna industry. Such facilities, it was felt, 

 might be diverted to the transportation of frozen salmon from distant fishing 

 grounds to canneries in other areas. 



Tuna have been successfully frozen and canned for a considerable number of 

 years, and ordinarily no great difficulty is encountered. In applying the same 

 technique to canned salmon, however, certain difficulties may arise which are avoided 

 when tuna are canned. Salmon are canned by a process in which the fish are cooked 

 and heat-processed in the sealed can, whereas tuna receive a "pre-cook" before being 

 placed in the can. This pre-cooking process gives a chance for certain undesirable 

 products which may have formed while the fish were frozen to escape. Furthermore, 

 the skin and often the dark meat lying just beneath and which contain much of the 

 oxidized oil are removed before tuna are canned. Accordingly, with regard to canning 

 of frozen salmon it is necessary to examine the situation very carefully, and it is 

 not sufficient to conclude that merely because frozen tuna can be successfully canned, 

 the same must also apply to frozen salmon. 



During the past two years, the Fish and Wildlife Service technological labora- 

 tories at Seattle and Ketchikan have been carrying out experiments on the canning 

 of frozen salmon. Salmon have been canned from fish which had been frozen round and 

 ♦ chief, pacific coast and Alaska technological research, branch of commercial fisheries, u. s. 



FISH AND wildlife service, SEATTLE, WASHINGTON. 

 ** CHIEF, FISHERY PRODUCTS LABORATORY, BRANCH OF COMMERCIAL FISHERIES, U. S. FISH AND WILDLIFE 

 SERVICE, KETCHIKAN, ALASKA. 

 1/PRESENTED AT THE NATIONAL CANNERS ASSOCIATION ANNUAL SALMON CUTTING MEETING, MARCH 9, 1951, 

 SEATTLE, WASHINGTON. 



