PROCESSING FISH MEAL AND OIL 235 



incinerators, or both in combination, have been widely used to largely 

 eliminate odor of this origin. Other odor sources are the raw fish, which 

 spoil rapidly in vessel hold or raw box, and liquids dripping from the raw 

 box, from raw fish conveyors, and from the quarter box and dewatering 

 screen where the raw fish are measured. Control of these odors is mainly 

 a matter of ''housekeeping," that is, good cleaning after every run of fish. 

 Water pollution results if the pump water that is added to the hold to 

 flow the fish into the suction pipe is discarded as it is separated in the 

 dewatering screen. In many areas regulations against water pollution pre- 

 vent discarding this in waters adjacent to the plant, and the pump water 

 is recirculated. Under these circumstances, these pump liquors build 

 up a fairly high solids and oil content, and plants have made a virtue 

 of necessity by recovering this material in the oil centrifuges and solubles 

 evaporators. 



The solubles-evaporator plant is usually not a source of odors, since 

 the jet ejector acts as a wash tower in condensing the evaporated, odor- 

 carrying vapors. However, an exception should be noted — the hot-air 

 solubles evaporators discharge large volumes of odoriferous gases into the 

 air and this type of evaporator is not likely to be tolerated unless located 

 a considerable distance from built-up areas. 



Problems associated with fish reduction as a business venture are 

 explored in somewhat greater detail in the U.S. Fish Reduction Industry^. 



LITERATURE CITED 



1. Butler, C, "The Fish Liver Oil Industry," Fishery Leaflet No. 233, Washington, 



Fish and Wildlife Service, 1948. 



2. Harrison, R. W., ''The Menhaden Industry," Investigational Report No. 1, 



Washington, Bureau of Fisheries, 193L 



3. Lassen, S., U.S. Patent 2,372,677 (April 3, 1945). 



4. Lee, C. F., Com. Fisheries Rev., 16, No. 9, 21(1954). 



5. Levin, E., Food TechnoL, 13, 132(1959). 



6. Olden, J., Com. Fisheries Rev., 22, No. 1, 12(1960). 



7. Ousterhaut, L. E., and Snyder, D. G., "Effect of Processing on the Nutritive Value 



of Fish Products in Animal Nutrition," FAO International Conference on Fish 

 in Nutrition, R/IV, 1(1961). 



8. Pariser, E. R., "Fish Flour-Technological Developments in the United States of 



America," FAO International Conference on Fish in Nutrition, R/V, 2/4 (1961). 



9. Sanford, F. B., and Lee, C. F., "U.S. Fish Reduction Industry," Technical 



Leaflet No. 14, Washington, Bureau Commerical Fisheries, 1960. 



10. Simmons, R. O., Com. Fisheries Rev., 20, No. 11a, 15(1958). 



11. Thompson, J. R., and Haskell, W. A., Petfood Industnj, 2, No. 12, 10(1960). 



12. Thorpe's "Dictionary of Applied Chemistry," 4th Ed., Vol. 8, p. 166, New York, 



Longmans, Green and Co., 1947. 



13. Thorpe's "Dictionary of Applied Chemistry," 4th Ed., Vol. 9, p. 40, New York, 



Longmans, Green and Co., 1947. 



14. Worsham, E. M., and Levin, E., U.S. Patent 2,503,312 (April 11, 1950). 



