FISHERY INDUSTRIES OF THE UNITED STATES, 1929 715 



now being conducted by various Federal and State agricultural 

 experiment stations. 



During 1929 the bureau published Document No. 1065, entitled 

 "Bibliography on Cod-liver Oil in Animal Feeding, with Noncritical 

 Comments and Abstracts." This pul)lication contains more than 

 200 references on this subject and has proved of value to both fishery 

 and agricultural industries. 



IMPROVED HANDLING OF FRESH AND FROZEN FISH 

 RUSTING AND PREVENTIVE MEASURES 



One of the problems confronting the producers of frozen fish is 

 the oxidation of the fats in fish causing them to "rust." This is the 

 result of a chemical reaction between the oxygen of the air and the 

 oil and fat found in fish. It is particularly noticeable on the cut 

 surfaces of the fish where the protective covering of the skin has been 

 removed. In order to prevent this reaction it is necessary to protect 

 this cut surface from contact with the air. The usual method for 

 accomplishing this is by glazing the fish with a thin coat of ice. 

 This, however, evaporates, and it has been found necessary to reglaze 

 them at frequent intervals, which adds to the cost of storage. Several 

 different methods are being tried for prevention of the contact be- 

 tween the surface of the fish and the oxj^gen of the air, and the 

 preliminary results seem to indicate that some of these will prove 

 very satisfactory. 



LEACHING OF FOOD AND MINERAL VALUES 



I has been recognized for several years that there is appreciable 

 loss of food value and mineral constituents when fish are packed in 

 contact with crushed ice. The water from the melting ice drips over 

 the fish and results in a leaching effect. 



The losses incurred in weight of the fish and food and mineral 

 value have never been determined, and very little has been done to 

 prevent losses of this nature. In preliminary experiments it was 

 found to be as high as 4 pounds per ton over a period of seven days. 

 This apparently is not a great loss until it is multiplied by the amounts 

 of fish handled in crushed ice over a period of a year; then it begins 

 to assume proportions which are really surprising. 



In this same consideration it should be emphasized that the flavor 

 and mineral constituents of the fish are the most important constit- 

 uents which are most readily lost by leaching, and if losses of this 

 nature are reduced the taste and food value of the fish will be little 

 impaired from that as originally caught. 



FORKING FISH ELIMINATED 



It has been the universal practice to use forks for transferring fish 

 when unloading the catch; this is detrimental to the fish, for the 

 reason that the holes made by the forks allow bacteria to gain more 

 ready access to the flesh of the fish, which in turn causes more rapid 

 deterioration of the fish. 



At the Boston fish pier, platforms have been installed for unloading 

 the vessels and boats which eliminates to a large extent the use of 

 the fork. Besides this, the platform method eliminates a part of the 



