THE AMERICAN SHRIMP INDUSTRY 599 



one filling the cans while the other adjusts them to the correct weight. No. 1 picnic 

 (211 X 400) cans are used for the largest part of the pack. If 'wet-pack' shrimp are 

 canned, the drained weight must be 5% ounces for this size container. It requires a fill 

 of 5^ ounces of shrimp meat as there is a slight increase in weight during processing 

 because of absorption of the brine. 



" 'Dry-pack' shrimp in No. 1 cans are required to have a net weight of 5 ounces and 

 are given a fill-in weight of 5/8 ounces as there is a slight shrinkage in this method of 

 processing. Cans for 'dry-pack' shrimp are usually lined with a one-, two-, or three-piece 

 vegetable parchment paper liner. A three-piece liner may be placed in the can more 

 readily than a one-piece liner. All cans are inside lined with 'C'-enamel, seafood formula. 

 Other sizes of cans used commonly, together with the fill-in weights are : squat ( 307 X 

 400 ) ; 'wet pack,' 9/4 ounces and 'dry pack,' 9 ounces. 



"The filling is watched by an inspector who removes occasional cans from the conveyor 

 belt, checks the weights, empties out the contents, counts the number of shrimp to check 

 the grade, and watches for evidence of poor workmanship, such as broken meats and bits 

 of shell. In packing 'wet-pack' shrimp two methods are used in filling the cans with 

 brine. In some establishments sprays of hot 2 per cent brine fill the cans as they pass 

 along a conveyor belt to the closing machine. In other canneries a 50- to 75-grain salt 

 tablet, the size varying with the container, is dropped into each can, which is then filled 

 with hot water as it passes along the belt. The tablets may be added either by hand or 

 from a mechanical dispenser." 



Exhausting and Sealing. " 'Wet-pack' shrimp are sealed immediately by a closing 

 machine operating at a speed of 60 cans per minute. As the cans are filled vdth hot 

 brine, creation of a vacuum mechanically or by heat exhaust is regarded as unnecessary. 



" 'Dry-pack* shrimp may be given a mechanical vacuum seal, or the cans may be 

 sealed cold, without heat exhaust or mechanical vacuum. Vacuum-packed shrimp are 

 regarded to be of superior quality, have a better color and flavor than nonvacuum packs, 

 and constitute about 75 per cent of the production of 'dry-pack' shrimp. Regulations of 

 the U. S. Food and Drug Administration require a vacuum of not less than 12 inches in 

 the can after processing if it is to be labeled vacuum pack. The same process is given as 

 for a nonvacuum pack. The process is shorter only if the cans are sealed with a vacuum 

 in excess of 25 inches." 



Processing or Retorting. "The sealed cans are stacked in retort baskets which hold 

 about 640 No. 1 cans. A retort has a capacity of either 2 or 3 baskets. 'Retorting' or 

 'cooking' is controlled closely under the inspection regulations, which also specify process 

 times and temperatures. 'Wet-pack' shrimp in No. 1 or squat cans are processed 20 

 minutes at 240° F (115.7° C) (10-pound pressure), or 10 minutes at 250° F (121.1° C) 

 (15-pound pressure). No. Da cans are processed for 23 minutes at 240° F (115.7° C), 

 or 12 minutes at 250° F ( 121.1° C). 'Dry-pack' shrimp in No. 1 or squat cans are 

 processed 85 minutes at 240° F (115.7° C), or 60 minutes at 250° F (121.1° C) if the 

 can is lined with a one-piece parchment liner. If there is no liner or if a three-piece liner is 

 used, the process is 70 minutes at 240° F ( 115.7° C), or 53 minutes at 250° F ( 121.1° C). 

 While processing at 240° F ( 115.7° C) is permitted, the use of a 250° F ( 121.1° C) 

 process is recommended as the better canning practice." 



Cooling and Washing. "At the end of the processing period the cans are water-cooled 

 to a temperature of 98° F (36.7° C) before they are stacked in the warehouse. Canned 

 shrimp may be cooled in special tanks or in retorts. In the more up-to-date canneries, 

 or in the great majority of cases, the pack is cooled in retorts. In canning 'wet-pack' 

 shrimp cooling in the retorts aids in preventing overcooking and softening, while in 'dry- 

 pack' shrimp it aids mechanically in pushing the can ends back in place, that is, where a 

 nonvacuum seal is used. Alkaline solutions are not required in cleaning shrimp cans after 

 processing." 



