vitamin A. A series of experiments are being conducted to test the adapt- 

 ability of the alkali digestion process now employed comnercially for the 

 manufacture of vitamin A oils from fish livers to the preparation of vitamin 

 A oils frcm the salmon offal. Anderson (l) has published a report of pre- 

 liminary research utilizing the alkali digestion technique for the recovery 

 of fish body oils from the head and collar section of the salmon cannery 

 offal. I>uring the past summer this method was tested on a larger scale 

 at the cannery of the Alaska-Seldovia Packers, Incorporated at Seldovia, 

 Alaska. 



(1) Anderson, L. A preliminary report on an alkali process for the manufacture 

 of ccMiBnercial oil from salmon cannery trinmings. Fishery Market News, Vol. 



7. pp. A-7. i?4$» 



Purpose of the Investigation 



Two phases of the investigation were carried out at Seldovia. The 

 technique for the alkali digestion of cannery offal was developed to con- 

 form to the most efficient methods practicable under the ccaiditions to be 

 found in a small cannery and with the limited f?icilities available for a 

 field operations laboratory. After the digestion technique proved to be 

 satisfactory, representative samples of offal direct from the cannery's 

 "Iron Chink" were processed into oils for subsequent vitamin A analyses. 



Collection of Raw Materials 



The salmon as received at the cannery, are sorted by species into 

 separate bins holding approximately 10,000 fish. When the canning operation 

 begins the fish are moved from the storage bins to the mechanical butchering 

 machine — the "Iron Chirik" — by a sluice and a slatted conveyor. The head 

 is severed from the body by the butchering operation in equipment known 

 as the header before the fish is sent to the "Chink" proper, "^he severed 

 head (and the major part of the liver) falls through a hole in the floor 

 into a flume where a stream of water carries it to the offal scow. A rep>- 

 resentative sample of the heads was thus obtainable by the removal of an 

 occasional head as they passed to the offal scow. 



The "Iron Chink" proper removes the fins, tail and viscera of the 

 decapitated fish body. Since the machine performs these several removal 

 operations at different points in the traverse of a circular path, the offal 

 is reasonably well segregated as to type. Assuming that the fish's tail is 

 engaged at a point corresponding to 3 o'clock and that the fish then 

 travels in a counter-clockwise direction, the fins and tail (and occasionally 

 the balance of the liver) drop to the sluice-way almost exclusively in the 

 first 90-degree sector and the last 90-degree sector of the circular tra- 

 verse. The viscera, consisting for the most part of the digestive tract 

 (stomach, caeca, spleen and intestine), part of the liver, and the gonads 

 is swept from the body cavity in the middle portion of the cycle. A chute 

 to direct this portion of the offal over a sorting table facilitated the 

 collection of a representative sample of the viscera. At first, only 



36 



