BARNETT ET AL. : USE OF CARBON DIOXIDE IN BRINE 



Figure 1. — Arrangement of the brine chiller (on the left) ; the pump is (on the floor) for circulating the chilled 

 brine through the cooling coils shown wrapped around the uninsulated holding tanks. 



Bacteriological Measurements 



Materials and methods. — Described here are 

 the rockfish and brine samples we used and the 

 methods of making total plate counts. 



The rockfish, Sebasfodes flavidus. were caught 

 in a trawl off the coast of Oregon. In the prepa- 

 ration of the samples, 130 lb. of the fresh, whole 

 fish was divided into two equal lots. Each lot 

 was placed in a polyethylene-lined drum of brine 

 at a one-to-one ratio by weight of fish to brine. 

 At this time, the iced fish had been out of the 

 water 24 hr. The ratio by weight of fish-to- 

 brine was maintained throughout the experi- 

 ment by removing a known weight of brine at 

 each sampling period. 



One tank of brine was treated with CO2 gas 



before the fish were loaded into it. The brine 

 in both tanks was cooled to 31° it 0.5° F during 

 the experiment. 



Periodically three fish and a sample of brine 

 were removed from each of the storage drums 

 for examination. The fish samples were used 

 to make both the objective and subjective mea- 

 surements at each sampling. 



Total bacterial plate counts were made on the 

 fish by the methods described by Pelroy and Ek- 

 lund (1966). Briefly, the method was as fol- 

 lows: a slice of flesh was removed from near 

 the dorsal side of each fish just posterior to the 

 nape. Each subsequent experimental sampling 

 was made from the same side and area of each 

 fish tested. Forty-five grams of fish from the 

 excised samples was homogenized aseptically 



435 



