12 U. S. BUREAU OF FISHERIES. 



tribution of fish; that it gives an unquestionably superior product; 

 that such difficulties as have been encountered are not insuperable; 

 and that the proper design of suitable plants is the principal problem 

 ahead. 



THE FRY BATH IN CANNING SARDINES. 



In the process of canning sardines in southern California, after the 

 fish have been scaled and cleaned they are brined in a strong salt 

 solution, dried, and then fried by being passed through a cottonseed- 

 oil bath heated to a temperature of from 100 to 115° C, after which 

 they are cooled and packed in tins with the proper sauces, then sealed 

 and retorted. The fry bath consists of a long metal tank with a 

 horizontal set of steam coils, midway of its depth, and an endless- 

 chain conveyor passing over the coils carrying the trays of fish 

 throughout the length of the tank. The tank is filled with water 

 almost to the bottom of the coils, and sufficient oil is added to cover 

 the baskets of fish passing through. With continued use the oil 

 becomes viscous and almost black in color and acquires a disagreeable 

 taste and odor. In addition some of the oil is carried by the fish to 

 the tin and detracts from the quality of the pack. The packers have 

 endeavored to diminish these difficulties by mechanical and chemical 

 treatment, as the frequent renewal of the oil is expensive, but have 

 met with little success. In view of the large quantity of oil used, the 

 failure to develop satisfactory means of purification, and the effects 

 on the character of the pack, the problem is one of some importance. 

 A study of the changes taking place in the oil used has been made at 

 the bureau's experimental laboratory at San Pedro, Calif., and the 

 following conclusions have been reached : 



1. The use of corn oil and a hydrogenated oil, in addition to cotton- 

 seed oil, for frying sardines is feasible. 



2. The presence of varying quantities of fish oil and the action of 

 air and heat are largely responsible for the changes which take place 

 in fry-bath oil. 



3. Sardine oil is present in varying quantities in the fry bath in 

 which sardmes have been fried. When fat sardines are used its 

 increase is so rapid that in a short time the fish are being fried in 

 oil which is largely fish oil. To keep the fish oil content of the fry 

 bath as low as possible, the sardines should be fried in the minimum 

 quantity of oil that can be used. This is applicable to all cases 

 except when fat sardines are being used with resultant increase in 

 oil content of bath. In such cases the oil should be allowed to in- 

 crease as far as conditions will permit and as long as such a condition 

 exists. 



Attempts to reclaim used fry-bath oil by chemical treatment were 

 unsuccessful. It is improbable that a cheap successful method will 

 be developed. The presence of small amounts of the fry-bath oil 

 can be detected in the canned sardines when they are eaten, and 

 it is believed cause the lingering taste often observed some hours 

 after one has eaten a considerable quantity of the fish. 



In conclusion, the investigation points to the desirability of 

 developing a satisfactory substitute for the fry bath. It is probable, 

 however, that no method developed will wholly displace frying in 

 oil, as the trade in some quarters appears to demana fish put up in 



