THE VENEZUELAN SALT-FISH INDUSTRIES 

 SUPPLaiENT 



STUDIES ON THE CONTROL OF "REDDENING" IN SALT-FISH PRODUCTS 



Joseph F. Puncochar and Francisca Arana 



Fishery Technologists 



U. S. Fish and Wildlife Service 



Mayaguez, Puerto Rico 



INTRODUCTION 



The United States Fishery Mission to Venezuela reported that control of the "reddening" 

 of Venezuelan salt-fish products was the most important single prerequiste to their entry 

 into export trade. It was the opinion of the mission that the spoilage of salt-fish by 

 reddening was so serious that large-scale production should be held in abeyance until the 

 control methods used in other countries could be studied and recommendations could be made 

 for the application of preventive measures in the Venezuelan industry. Such reconniendations 

 would naturally have to take into account the variations between the domestic and the foi^ 

 eign industry. These differences occur in the preparative methods and equipment, the spe- 

 cies of fish preserved, the kind of salt available, the climate, and many less apparent 

 factors. 



For many years, one of the most important components of the diets of the people of 

 the Caribbean countries has been imported salt-fish. The shortage of transportation brought 

 about by the war quickly led to a critical and widely-felt scarcity of this highly necessary 

 food. With a view to relieving this pressing deficiency, the mission recomnended that the 

 suggested studies be immediately undertaken at the Fishery Research Laboratory of the United 

 States Department of the Interior, at Mayaguez, Puerto Rico. 



ISOLATION, CULTURE AND MORPHOLOGT 



The spoilage of salted foods, hides, sausage casings, etc., by reddening has been the 

 subject of many microbiological treatises published during the last sixty years. The work- 

 ers in this field have described several different causative agents and have given vari- 

 ous names to the salt-tolerant (halophilic) , red-colored microorganisms that infested the 

 spoiled products. Harrison and Kennedy (1922) isolated such an organism and designated 

 it as Pseudomonas Salinaria . This is only one of many such isolations and appellations, 

 but it is not necessary here to review exhaustively the many articles dealing with the topic, 

 Petrova (1935) » in studying the characteristics of the infections of various Russian salt 

 deposits, came to the conclusion that the majority of the authors had all described the 

 same bacterial species, but had observed it in different stages of its development. This 

 opinion was based on the marked tendency of the species, as noted also by many other in- 

 vestigators, to modify itself in response to internal and external influences. 



The majority of the samples grown in the laboratory showed alterations of morphological 

 and cultural properties. The individuals took the appearance of cocci or rods, and the 

 colonies varied from translucent deep red to opaque pale pink, sometimes changing shades 

 in cycles. There was also a marked inclination to symbiosis with other bacteria. The growth 

 of the reddening organisms is often strongly inhibited in laboratory cultures by concentra- 

 tions of salt that seem to be easily tolerated under natural ronditions. It has been sug- 

 gested that the symbiotic relationship helps to overcome the repressive effect. 



From the review of the literature it was felt that the reddening organisms encountered 

 in Venezuela might be a distinct species, or a modified strain of one previously described. 

 Consequently, it was deemed advisable to study the morphology and cultural characteristics 

 as a preliminary to the testing of control methods. 



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