THE CURING AND PRESERVATION OF FISH 113 



will, therefore, be delayed, and in warm weather (above 

 70F.) this may result in the souring of the fish. 



To obtain rapid and thorough curing, therefore, it 

 is necessary especially in warm weather to use salt 

 which contains as little calcium and magnesium salts as 

 possible. 



Pure salt, used dry, produces a soft, yellow-meated 

 fish which is flexible in the hand. Salt containing 

 calcium chloride or magnesium chloride produces a 

 harder and stiffer fish with a markedly whiter colour. 



Salted fish can only be stored satisfactorily in a dry 

 place. Fish which has been cured with impure salt 

 is hygroscopic and will run wet in the store. 



This hygroscopic moisture weakens the preserving 

 action of the salt. Fish that has been cured with a 

 pure salt will keep much drier under ordinary storage 

 conditions. 



(2) 7/s Grain. The crystals of Fishery Salt should be 

 coarse and hard. Coarse crystals dissolve slowly, and 

 so produce a more gradual cure than fine-grained salt 

 does. Fine-grained salt extracts the water so rapidly 

 from the surface tissues that it coagulates them. This 

 retards the further penetration of the salt into the fish, 

 so that the fish has the appearance of being slack salted. 



Round versus Cleaned Fish. The thoroughness with 

 which a cut fish is cleaned and washed influences the 

 temperature at which the fish can be salted success- 

 fully, and materially affects the quality and taste of 

 the product. Tressler 1 has shown that the chief cause 

 of fish spoiling when salted in hot weather is the decom- 

 position of the blood which remains in the flesh. Even 

 in cold weather, it is found that the extra washing and 

 cleaning greatly improve the quality of the fish. As the 

 presence of blood in the fish also leads to discolouration 



1 U.S. Bureau of Fisheries, Document No. 884 (1920). 



