CANNING OF FISH AND FISH PRODUCTS 



447 



atmospheric temperature, and in still others tanks of water receive the fish to be 

 defrosted. 



Butchering and Inspecting. When the tuna are completely defrosted, the heads 

 and viscera are removed. The body cavity is washed thoroughly to remove all 

 traces of blood. A State Health Department inspector examines them for decom- 

 position before the process is continued. This examination insures that only those 

 in first-class condition reach the cans, 



Precooking. The tuna are placed on racks which are run into large steam 

 chambers or cookers. The cooking time is usually from 2}2 to 4 hours at 212 to 

 216° F (100 to 102° C), depending on the size and condition of the fish. The 

 racks are then run out and allowed to cool in an air current for at least 12 hours. 



{Courtesy U. S. Fish and Wildlife Service) 



Fig. 20-10. The eviscerated and cleaned tuna are placed in racks 

 or baskets for precooking. This removes the excess oil and softens the 

 flesh so that the skin and bones can be removed. 



or until the flesh has become firm enough to be handled without being broken. 

 The fish are then easily skinned and beheaded, and separated into 4 longitudinal 

 sections. After removal of the dark meat the strips of white meat are cut into 

 proper lengths to fit the cans, into which they are packed, and salt and oil are 

 added mechanically. Cottonseed oil is commonly used, /* of an ounce for each 

 No. /2 (7-ounce) can. The dark meat is also canned to a considerable extent, but 



