556 



U. S. BtTREAU OF FISHERIES 



protein of fish on long cold storage, called " souring " by the prac- 

 tical freezer man. The activities of bacteria are greatly retarded by 

 freezing but apparently are not absolutely arrested, for some fish on 

 long storage develop a sour odor. Pickerel, especially if frozen 



Fig. 18. — Storage room in a public freezer. For separately frozen fish, not boxed, 

 bins are provided to keep the lots separate, so that they are accessible for 

 delivery at any time. Tags for lot numbers and dates are attached to each bin. 

 Courtesy, Brooklyn Bridge Freezing & Cold Storage Co. 



round, are prone to sour and may do so in a few months at 0° F. 

 Ciscoes also are subject to this trouble, especially if round, but the 

 trouble is slow to develop. Perhaps the intestines or contents of the 

 alimentary canal are chiefly concerned in souring. 



The temperature must not only be low but also as constant as 

 possible. Fluctuating temperature promotes drying of the fish. The 



