84 U. S. BUREAU OF FISHERIES 



A quick method for determining the condition of the oil present 

 in fish flesh was developed. This method involves an extraction of 

 the oil by shaking the flesh with ether and sodium sulfate, a process 

 which eliminates the decomposition of the oil usually encountered in 

 the ordinary methods of oil extraction. The extracted oil is then 

 available for chemical tests such as a determination of the peroxide 

 number. The method is suitable for a rapid determination of the 

 oil content of the fish. 



ELECTROMETRIC TESTS FOR FRESHNESS OF COD AND POLLOCK 



In May 1933 a report was published dealing in considerable detail 

 with a method developed in the laboratory for the determination 

 ■electrometrically of the relative freshness of haddock.^ It was stated 

 in that paper that it would be necessary to complete a series of actual 

 tests in order to establish an accurate index which would make the 

 test applicable to other species. During the past year, this was done 

 in the case of cod and pollock showing that the method is applicable 

 for testing the relative freshness of these species, 



STUDIES ON SMOKING FISH 



A few preliminary studies were begun to determine the effect of 

 the chemical nature of wood smoke relative to its preservative effect 

 upon fish. Sawdust was heated in a combustion furnace and the 

 resulting smoke collected and analyzed. As yet, not sufficient results 

 have been obtained to draw any conclusions. 



STUDIES OF RANCIDITY IN FISH 



As mentioned in previous annual reports of this Division, our tech- 

 nological staff has been much interested in the causes and prevention 

 of the development of rancidity in fatty fish. Especially has this 

 been a problem in connection with the cold storage of such oily fish 

 as mackerel. As facilities were available and as time would permit, 

 our technologists worked on this problem. Because of the limitations 

 of our facilities and the size of our staff, very little time could be given 

 to this project and its study was pursued only intermittently and in 

 connection with the study of other research problems which were 

 affected by it. 



However, late in 1935, the Musher Foundation of New York City, 

 a privately endowed research agency and technical consulting organi- 

 zation, became much interested in the published reports of our 

 technologists bearing on the problem of rancidity in fish. Since the 

 Musher Foundation had also made considerable study of this problem 

 as related to fish and other foods, arrangements were made for a 

 cooperative investigation in our laboratories and research associates 

 were employed by the IVIusher Foundation to carry on this work. 

 The first phase of the project has consisted of tests of the value of 

 various cereal flours, such as oat and rice flour, as inhibitors of the 

 development of oxidation or rancidity in fatty foods. These cereal 

 products had already been shown to be of value for preventing or 



3 "An electrometric method for detection of relative freshness of haddock", by Maurice E. Stansby and 

 James M. Lemon. 



