FISHERY INDUSTRIES OF THE UNITED STATES, 1931 105 



IMPROVED METHODS FOR SMOKING FISH 



In general commercial procedure it has been difficult to produce a 

 uniform smoked fish product for the reason that no standards have 

 been established for the methods involved or for the finished product. 



In order to assist the industry in this respect the division is conduct- 

 ing a study of the smoking of fish. 



During the past year James M. Lemon designed and had constructed 

 at the Gloucester Laboratory an experimental smokehouse and with 

 the assistance of Maurice E. Stansby, conducted studies on the smok- 

 ing of fish. The smokehouse is portable and is constructed to reduce 

 the fire hazard to a minimum. The smoke is produced in the lower 

 section by feeding sawdust onto an electric hot plate. This sawdust 

 is fed automatically from a hopper onto the electric burner, where it is 

 mechanically distributed over the surface to produce an even smoke. 

 The volume of smoke can be controlled by adjusting the speed with 

 which the sawdust is fed into the burner. A blower forces the smoke 

 from the burner, through the upper section or smoking compartment, 

 thence to an exhaust to the air outside. A draught regulator is 

 attached to this system which makes it possible to produce as rapid 

 circulation as may be desired. 



The smoldng compartment in which the fish are hung is heated by 

 an electric heater, the temperature of which can be accurately con- 

 trolled. This makes it possible to study the eft'ect of difterent tem- 

 peratures on the fish. 



The humidity in the smoking compartment is controlled by means 

 of a water spray. This may be employed to increase the amount of 

 moisture present in the smoke. Circulation of the smoke in this 

 compartment is accomplished by an agitator. A continuous record 

 of the temperature and humidity of the smoking compartment can be 

 kept by means of recording instruments. 



It is possible to duplicate previous results by manipulating the 

 controls regulating the volume of the smoke, temperature, and humid- 

 ity. Application of this method to commercial procedure should 

 remove much of the guesswork from the art of smoking and enable 

 producers to manufacture a uniform product. 



BACTERIOLOGICAL STUDIES 



In the marketing of fresh fishery products and in their preservation 

 by freezing, drying, salting, smoking, or canning various bacteriologi- 

 cal changes take place which may hasten decomposition, contribute to 

 preservation, or otherwise influence the manufacture of the finished 

 product. These changes have received Httle attention by research 

 workers with the result that losses in the fisheries, due to lack of 

 knowledge of bacterial action, are enormous. In an effort to improve 

 those processes or methods affected by bacteria the division established 

 a bacteriological laboratory at its technological station in Gloucester^ 

 Mass. This research work during the past year was conducted by 

 Francis P. Griffiths and has been concentrated upon detennining the 

 germicidal effect of smoke on fish and the nature of molds on smoked 

 fish and their prevention. The bacteriology of fresh and frozen fish 

 also has received attention. In this connection, it has been definitely 

 shown th at wounds produced in forking fish are fertile breeding grounds, 

 for bacteria. 



