Chapter XVII — 197 — Economic Importance 



spoilage of raw furs, fish, caviar, meat, pickles, and other products on 

 which salt is used as a preservative. According to Raiin (1934), natural 

 rock salt as well as crystallized salt manufactured from rock salt is prac- 

 tically free from bacteria, except such as it may gather up in the process 

 of shipment, storage, and handling. However, salt from marine or solar 

 salterns often carries halophilic bacteria (Clayton, 1931). Clayton and 

 GiBBS (1927) traced pink halophiles to sea salt which stained salted hides 

 and produced pink blotches on salt fish. 



Browne (1922) traced the discoloration of fish to Bacterium halo- 

 philiciun, which was isolated from sea salt along with Spirochaeta halo- 

 philica. Baumgartner (1937) discovered Bacteroides halosmophilus in 

 salted anchovies. The red, brownish, and other spoilage organisms 

 associated with salted food products were traced by Petrowa (1936) to 

 saline lakes from which the salt was reclaimed. Other problems attending 

 the preservation of food with solar salt are discussed by Tanner (1944)- 



The cause of the discoloration of salt codfish was shown by Harrison 

 and Kennedy (1922) to be Pseudomonas salinaria that had been intro- 

 duced with solar evaporated salt used in curing the codfish. It, like 

 Sarcina litoralis, Bacterium trapanicum, and several other species of halo- 

 philes isolated from salt samples and spoiling salt fish by Gibbons (1937), 

 grew in media containing 20 per cent NaCl. Hof (1935) gives additional 

 information and literature on bacteria which cause the spoilage of various 

 foods in concentrated salt solutions. He points out that halophilic bac- 

 teria are widely distributed in salt lakes, limans, salt gardens, soil, and 

 elsewhere in nature. 



Stuart (1936) detected the presence of proteolytic and chitinoclastic 

 bacteria in nearly all of the 27 samples of solar salt which were examined 

 from different parts of the world. He likewise noted the association of 

 chromogenic halophiles with the reddening of salted fish and hides. Stu- 

 art believes that halophilic bacteria introduced with salt used for curing 

 may be responsible for damage to skins and hides. Using silica gel media 

 containing 14.5 per cent salt, Moore (1940) demonstrated the presence of 

 halophilic bacteria in several samples of packing house salt, crude solar 

 evaporated sea salt, tainted steer hides, and tainted sealskins. Before 

 effective control measures were taken, microorganisms damaged large 

 numbers of Alaska sealskins which had been packed with salt as a pre- 

 servative on the Pribilof Islands preparatory to shipping to the processing 

 plant in the States. 



Spoilage of marine food products : — Reference has already been made 

 in preceding chapters to the microorganisms which cause spoilage of oys- 

 ters and fish. Such microorganisms present special problems to food 

 technologists, because many of the microorganisms are active at the tem- 

 perature of ice, some grow in concentrated salt solutions, others are both 

 psychrophilic and halophilic, and fish tissues are very susceptible to de- 

 composition. Much progress has been made in recent years in improving 

 the quality of "fresh" marine food products by fast-freezing processes, 

 rapid transit, and more careful handling, but the marine microbiologist is 

 still confronted by numerous unsolved problems in this field. 



Typical of the problems confronting the section of the canning indus- 

 try specializing in sea foods is the blackening of lobsters. The thorough 

 investigations of Reed and MacLeod (1924), revealed that species of 

 Pseudomonas, Flavobacterium, and Bacillus, along with other natural bac- 



