At least 50 percent of The weight of the whole tuna, as landed, is not canned. 

 The so-called "waste" material is used to produce liver, solubles, liquid fertilizer, 



TUNA oil and meal. 



In some PLANTS THE LIVERS ARE SEPARATED FROM THE OTHER VISCERAL MATERIAL AND 

 PROCESSED INTO LIVER OIL, IN OTHER PLANTS ALL OF THE VISCERA, INCLUDING THE LIVERS, 

 IS USED FOR THE PRODUCTION OF FISH SOLUBLES AND LIQUID FISH FERTILIZERS. ThE RE- 

 MAINING WASTE, INCLUDING FINS, hCAO, SKIN AfC BONES, IS CONVERTED INTO TUNA OIL 

 AND MEAL IN THE REDUCTION PLANT. 



The TUNA CANNING INDUSTRY UTILIZES ITS "WASTE" MATERIAL AS EFFICIENTLY AS 



any other segment of the domestic fishin3 industry. efficiency in tuna canning 

 might be improved either by saving labor or by increasing the yield of canned fish 

 obtained pen ton of raw fish processed. since shore labor amounts to no more than 

 10 to 12 percent of total costs, chances for making any substantial reduction in 

 costs by more efficient use of lbaor are not great, substantial labor saving could 

 be accomplished in the cleaning step if any of several different pieces of equipment 

 which are under development to clean tuna 'mechanically should prove successful, 

 a net saving in labor of perhaps 2?^ per case might be achieved. other steps in 

 the processing of tuna are fully or almost fully f^chanized and any improvements 

 vjhich might be made could only result in very small over-all savings. 



With the cost of the raw fish amounting to up to 70 percent of the total «08T, 

 savinqs res'jlting from increasing the yield of the canned product are potentially 

 quite large. over-all losses during precooking and cooling may be as much as 30 

 PERCENT. These losses may be cut down considerably by more careful control, but 



IF carried to an extreme, may alter the characteristics of THE FINAL PRODUCT, AND 

 result IN A PACK OF POOR APPEARANCE WITH REDUCED PROTEIN CONTENT f<fC NUTRITIVE 



VALUE. Some improvement in y'ield is possible, nevertheless, at LEAST by some OF 



ThE TUMA packers. 



On the WHOLE, THE TUNA INDUSTRY IS MAKING USE OF THE LATEST DEVELOPMENTS, AN3 



is operating at, or nearly at, maximum efficiency. 



When the precook time for tima is drastically reduced or eliminated entirely, 

 the resulting canned product differ^ from the conventional pack in the follow inq 

 principal respects: 



1. Considerably more aqueous fluid is. present in the can. 



2. The protein contents of the drained fish is less. 



3. The ;cntent of ^JATURAL tuna oil in the drained fish is greater, but the 

 total oil content (absorbed added vegetable oil and natural tuna oil) 



IS LESS. 



4.. The moisture content of the drained fish is greater. 



5. The texture of the flesh is somewhat less tendcr. 



6. If the precook is entirely eliminated, considerable curd occurs on the 



SURFACE. 



The texture of machine-packed fjsh may be somewhat different from that of 

 hand-packed fish. This results chiefly from absorption of a greater amount of 



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