588 MARINE PRODUCTS OF COMMERCE 



liquid is added to cover the contents. The processing time at the above tempera- 

 ture is 40 minutes for No. 1 cans. 



Jarvis (1943) gives the following recipe for Manhattan-style clam chowder: 



65 pounds cracker crumbs 24 No. 10 cans of tomatoes 



18 " ground salt pork 16 pounds salt 

 18 " ground onions 5 ounces white pepper 



55 gallons water 



When this chowder has been cooked and is ready to be canned, 2 ounces of clams 

 are put into each No. 1 can and sufficient liquid is added to fill the can. 



In New England clam chowder from % to M of the water is replaced by clam 

 juice. The clams are added either whole or coarsely minced rather than ground. 

 Diced blanched potatoes are substituted for tomatoes. The clams and potatoes 

 are placed in the can and the liquid ingredients are then added to fill the can. 



The Federal Food and Drug Administration has set forth regulations as to sani- 

 tation in the cannery, the required fill of the can, both solids and liquids, and 

 labeling. It is required that the drained weight shall equal 3/2 ounces for /2-pound 

 flat cans, 5 ounces for a No. 1 picnic size, and 8 ounces for a No. 1 tall can. 



Clam Extract. Clam extract finds extensive use as a food for convalescents and 

 invalids. It is usually prepared by placing fresh clams in the shell on racks or 

 gratings in an autoclave. The clams are steamed for about 20 minutes; the heat 

 cooks the clams and causes much of the juice to run out. The liquor is collected 

 in pans under the racks. This liquor is filtered and concentrated by boiling. The 

 concentrated extract is put into cans which are topped, sealed, and sterilized by 

 processing in an autoclave at 240° F (116° C). One-pound cans are heated for 

 an hour, whereas half-pound cans are usually heated for 50 minutes at this tem- 

 perature. Various other methods of preparing clam extract are occasionally used. 



Smoking, Salting, and Drying. Large quantities of clams used for fish bait by 

 New England fishermen were formerly shucked, that is removed from the shell, 

 and salted in barrels. The gradual decline of the hand-line fishery e£Fected a similar 

 decline in the clam-bait industry; at present only a few barrels of salted clams 

 are prepared annually for use as bait. 



Smoking and drying were the earliest means of preserving clams. The North 

 American Indians strung clams on sticks or cords and dried and smoked them 

 over camp fires. Even today, the Japanese and Chinese dry large quantities of 

 clams and other shellfish. The Japanese dry a clam {Solecurtus constrictus) re- 

 sembling the razor clam. 



By-products 



Shells are the only by-products of the clam industry. Inasmuch as the clam shell 

 possesses little value, its use is limited to oyster cultch, material for the construc- 

 tion of roads, and poultry grit. 



REFERENCES 



Ackerman, E. A., "New England's Fishing Industry," Chicago, Univ. of Chicago Press, 



1941. 

 Anon., "The Ocean Quahog Fishery of Rhode Island," a survey conducted by the U. S. 



Department of the Interior, Fish and Wildlife Service, in cooperation with the Divi- 



