rTxn.l/ATlON OF SIIIMMI' WASTK 115 



PREPARATION OF EXPERIMENTAL MEALS LOW IN SALT CONTENT 



T\w conversion of slii'ini[) wastes into meals low in salt entails 

 moi'e labor than the conversion of wastes into fertilizer, a procedure 

 which will be described later, but the processin**; is cleaner and the 

 returns on the product obtained are so much greater tliat it becomes 

 the moi-e economical method of utilizin«>; the wastes. There are two 

 <>:en.eral methods of treatin<2; the shrimp heads, {a) nonacid water- 

 cook and rapid dryinfj and {h) acid water-cook and drvin<!;. The 

 first method fjives a product low in soluble suli)hates, while the 

 latter g-ives a sulphate content dependent upon the amount of acid 

 added to the cook. The first requires no acid, but the drying or 

 reduction of the stock to al)out 40 per cent moisture content must 

 be carried out the same day that the shrimp are headed to prevent 

 spoilage. The second requires care in adding acid, but the product 

 with as high as 60 per cent moisture will not decompose for a j)eri<)d 

 of two days. 



NONACID W'ATER-COOK METHOD 



Cooking. — The shrimp waste is collected in 2-poled wire baskets of 

 50 to 100 pound capacity and carried to the community plant serving 

 the group of small shrimp handlers. Here the baskets are lowered 

 into a cooking vat steam heated, or heated by direct fire. A large 

 iron kettle will give satisfactory service but in that case the baskets 

 must be so constructed as to fit the circular kettle, ample space being 

 allowed around the basket to permit ready circulation of the boiling 

 water. The vats to be used for cooking shrimp wastes can also be 

 built of heavy timber, in square or rectangular shape to accommo- 

 date the baskets used in carrying the shrimp. The shrimp wastes 

 are loaded into wire baskets of a type similar to those used in the 

 cooking of the shrimp meat. These baskets are carried into the waste 

 shrimp cooking rooms and suspended into vats, where they are left 

 for 10 minutes after the water in which they are suspended reaches 

 the boiling point, or 212° F. 



/Solar drying. — The cooked waste, now quite pink in color, is carried 

 to a drying platform or dumped onto wire bottom frames to allow 

 free circulation of air through the mass. In this manner the sun will 

 evaporate the moisture. Tray drying is shown in Figure 3. These 

 trays can be so constructed that they can later be transferred to a 

 heat drier. If the sun is shining, the frames may be placed in the 

 sun and the drying started. The period of drying by solar heat 

 depends ujjon the thickness of the mass upon the screens, the time of 

 day, and the sequence of hours of sun'shine. In good sunshine, and 

 with a layer not over 3 inches thick, drying of the product to 10 per 

 cent moisture content is readily accomplished in 8 hours. A product 

 with as high as 15 per cent moisture may be stored several months 

 or more Avithout spoilage. This product can be accumulated and 

 further dried in a heated drier, when sufficient stock is on hand, and 

 then ground at leisure, or in the off season for shrimp. The final 

 drying should be carried below 8 per cent in moisture, the best prod- 

 uct for efficient grinding containing about 5 per cent moisture. 



Rapid heat drying. — In inclement weather and for the final drving. 

 the stock must be placed in heated driers. The type of drier to use is 



