THE VENEZUELAN SALT-FISH INDUSTRIES 



irapadring the color or flavor. Potassium nitrate is another agent often used in the pres- 

 ervation of meat products, sometimes in conbination with boric acid, borax, and sodium 

 chloride (Leach and Winton, 1914) t 



According to Framk and Hess (1941), salt-fish was effectively protected against "brown 

 halophilic mold" by being dipped for 30 seconds in an 0.8 molar solution of sodium propion- 

 ate in salt brine. Macy (1943) reported that sodium or calcium propionate could be safely 

 used to inhibit mold growth in food products for a reasonable period of time. 



Since some data were already available on the toxicity and flavor effect of the above- 

 mentioned chemicals when used in food preservation, it was decided to test their action 

 in the control of the reddening organism. First, their ability to inhibit the development 

 of reddening in culture media was determined. Then, when it became apparent that acidic 

 magnesium benzoate, a mixture of equal parts of benzoic acid and magnesium benzoate, was 

 the most effective of the agents tried, that mixture was tested further on the salt-fish 

 itself. 



Trial of Reagents in Laboratory Media 



A pure culture of the reddening organism was transferred to an agar slant and incu- 

 bated at 42° C until good growth appeared, A loopful of the culture was then transferred 

 into 30 milliliters of codfish and nutrient broths containing approximately 5 percent salt. 

 The codfish broth was prepared by boiling one pound (454 grams) of dry-salted codfish in 

 one liter of distilled water for one hour, filtering and adjusting the pH to 7.0. Bacterial 

 counts were made on the inoculated broths after 24 hours incubation at 42° C. One millili- 

 ter portions of the Inoculated broths were seeded into sterile tubes containing 10 millili- 

 ter aliquots of varying concentrations of the reagents to be tested dissolved in 5 percent 

 sodium chloride. 



The seeded tubes and blanks were incubated at 42° C. After intervals of 10, 30, and 

 60 minutes and 24 hours incubation, the tubes were removed, thoroughly shaken, and three 

 streaks were made from each tube on plates of codfish and nutrient agars . The streaked 

 plates were examined after 48 hours incubation for colonies of the reddening organism. Growth 

 in three streaks was classified as "abundant", in two streaks as "moderate", in one streak 

 as "scant", and no growth in any of the streaks as "sterile". The lowest effective con- 

 centrations of the various reagents producing sterile plates are recorded in Table 4, 



The preservative agents tested were: potassium nitrate, sodium benzoate, acidic mag- 

 nesium benzoate (a proprietary preparation known as "Brlno" composed of equal parts of ben- 

 zoic acid and magnesium benzoate), boric acid, sodium hypochlorite, calcium propionate, 

 and sodium propionate. Table 4 shows what concentrations of the preservatives were tried, 

 whether they made the culture non-viable, and in what length of time this result was ac- 

 complished. The acidic magnesium benzoate was by far the most effective control agent, 

 even when used in low concentrations. It was found that 0,1 to 0.5 percent of this pre- 

 servative destroyed the viability of the cultures of the reddening organism. Boric acid 

 was effective in concentrations of 2 to 3 percent, but its toxicity as reported by Pfeiffer, 

 Hallman and Gerah (1945) would tend to preclude its use in food. Sodium hypochlorite in 

 concentrations of 20 to 100 parts per million also accomplished the extinction of the via- 

 bility, but in actual use this chemical would probably soon lose its active chlorine, and 

 the salted product would then be likely to be contaminated anew. Sodium benzoate controll- 

 ed growth only when concentrations above 10 percent were used. This amount was shown by 

 Harsbarger (1942) to be injurious to health and would, therefore, probably not be allowed 

 by the various governmental authorities. Calcium and sodium propionate were tried in con- 

 centrations up to 3 percent, which was the highest strength tested by Harsbarger ( loc. cit. ) 

 that did not prove toxic to rats. Both of these salts were ineffectual in the proportions 

 used. Potassium nitrate, even in concentrations as high as 30 percent, was unable to pre- 

 vent the growth of the reddening organism. 



Trial of Acidic Magnesium Benzoate on Salted Fish 



The promising results given by the acidic magnesium benzoate in preventing the growth 

 of the reddening organism in laboratory media suggested that it would be advisable to con- 

 duct supplementary experiments using the same preservative preparation under conditions 



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