442 MARINE PRODUCTS OF COMMERCE 



Refrigerated Holding Tanks. The California pilchard industry has developed 

 refrigerated holding tanks for preserving the catch from one day to the next. These 

 tanks containing the fish are fitted with brine circulating systems. The refrigerated 

 brine, containing about 10 per cent salt, is held at 35° F (1.7° C) and circulated 

 through the tanks containing the fish, which are in duect contact with the brine. 

 It has been found that by this method fish can be held in excellent condition for 

 periods as long as 48 hours. 



Chemistry and Bacteriology of Sardines. Considerable study has been given to 

 the chemistry and bacteriology of sardines, references to which will be found 

 in the bibliography. Of particular interest is the recent work on changes which 

 sardines undergo in the course of preparation and storage. It has been found that 

 when stored canned sardines show a decided quantity of volatile nitrogenous 

 compounds, the greater part of which is in the form of amines. The percentage 

 of amines appears to correspond directly to the age of the product. During 

 processing or cooking there is an increase in the amount of ammonia and amines. 

 Storage produces a gradual increase of total alkaline material due to formation of 

 alkyl amines and a gradual decrease in ammonia. 



The alkaline compound predominating is trimethylamine (which is also exten- 

 sively formed in the storage of herring in brine and fresh fish in ice) . The tempera- 

 ture of storage apparently has a decided influence on the quantity of volatile 

 alkaline compounds formed. This suggests that changes may be due in some 

 instances to bacterial growth; anaerobic, spore-forming, gas-forming bacteria, 

 found associated with the fish, produce both ammonia and amines when grown 

 in fish products. This has a bearing on the detinning of cans and possibly on the 

 softening and maturation of the product. 



The principal food of the sea herring, from which Maine sardines are pro- 

 duced, is small animal organisms, including copepods, which constitute the so- 

 called "red feed," and schizopods, small shrimplike animals. With these organ- 

 isms are associated certain gas-producing bacteria which have a marked deteriorat- 

 ing effect on fish containing feed after they are taken from the water. The prob- 

 lem of avoiding trouble from so-called feedy fish of this kind is one of the most 

 serious connected with the industry. 



Herring containing feed in appreciable amounts should be held in the water 

 for a sufficient length of time so that this food may be digested. This can usually 

 be done with herrings taken in weirs; but in the case of fish captured with purse 

 seines and at certain seasons, it is much more difficult. Even fish taken in weirs 

 often contain so much feed that it is impracticable to prepare sardines of good 

 quality, particularly from the small fish; therefore, they are either left in the 

 seines or weirs imtil the food is digested, or promptly taken to the factory and 

 eviscerated. 



Oil for Sardines. Various investigations have been made on commercial olive 

 and cottonseed oils used in the canning of Maine sardines. Sixteen samples of 

 olive oil and 22 of cottonseed oil were included in this study. In testing olive oil 

 for this purpose they found the most valuable information could be secured from 

 the determination of acidity, appearance, and flavor. This does, not include tests 

 for adulteration with other foreign oils, for which special chemical or phvsical 

 tests must be applied. 



In the case of cottonseed oil the most helpful tests for quality were the de- 



