34 Commercial Shark Fishing in the Caribbean Area 



details than we are able to set forth in this giude could 

 be obtained by writing to the Anglo-American Carib- 

 bean Commission, 810 18th street, N.W., Washington, 25, 

 D. C. 



In general, however, this method of extracting the 

 oil is as follows : Grind or chop the shark livers thor- 

 oughly with a sausage meat grinder or a meat chop- 

 per, mix with water and pump into a steam-jacketed 

 kettle. This kettle should be fitted with a mechanical 

 stirring device and a means for blowing steam, at about 

 15 pounds pressure, through the liver and water mixture. 

 Add water to livers in a ratio of two parts of water to one 

 part livers. Then add two per cent caustic soda by 

 weight of livers to the liver and water mixture. The 

 caustic soda neutralizes any fatty acids present and also 

 aids in the digestion of the liver tissue. Heat the entire 

 contents of the kettle to 180° F., stir and blow live steam 

 through until digestion is complete. This takes about 

 twenty minutes. Draw off the entire contents of the ket- 

 tle and send through a centrifuge (like a cream separa- 

 tor) which is capable of separating the oil from the 

 gurry. Oil thus obtained is ready for shipment and needs 

 no additional processing. 



If a centrifuge is not available, the liver, oil and water 

 mixture will separate upon standing for about twenty- 

 four hours, and the oil will rise to the surface. Draw this 

 oil off. You may need to filter this oil through a linen 

 cloth in order to remove any suspended liver tissue. 



For both of the above methods of extracting oil, be 

 sure that you use only fresh livers, or those which have 

 a red appearance. Do not use any livers that have turned 

 black or dark brown, as one spoiled liver will ruin the 

 entire batch. 



Testing the Oil 



Testing for oil content and Vitamin A potency is an 

 essential step in the handling of livers. Since shark 

 livers and oils are bought for their Vitamin A content, 

 purchasers will want these tests made. It will also be 

 helpful for you to know the probable value of your ship- 

 ment before you attempt to market it. 



Accurate tests such as the purchaser would require 



