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Not only are there many varieties of shrimp worldwide, but there is a great diversity in product forms. Product can be divided into two basic types: raw and cooked. It can then be further divided into fresh and frozen. Within these broad categories, almost all shrimp in the U.S. market is sold as tails, and the bulk of that is sold frozen. Primary product forms for frozen shrimp are:

Green headless. The standard market form. Includes the six tail segments, with vein, shell and tail fin. “Green” does not refer to shell color but to the uncooked, raw state of the shrimp. Also called “shell-on” or “headless.” 

Peeled. Green headless shrimp without the shell. 

PUD. Peeled, undeveined, tail fin on or off; raw or cooked. The vein, running the length of the tail, is the intestine, also called the sand vein.

Tail-on, round. Undeveined shrimp with tail fin on. 

P&D. Peeled, deveined, tail fin on or off; raw or cooked. Another name for IQF P&D shrimp is PDI (peeled, deveined, individually frozen). 

Cleaned. Shrimp that is peeled and washed, a process that removes some or all of the vein but is not thorough enough to warrant the P&D label.

Shell-on cooked. Cooked tail, with vein, shell and tail fin. 

Split, butterfly, fantail. Tail-on shrimp that are cut deeply when being deveined. 

Pieces. Shrimp with fewer than four or five whole segments, for small shrimp and large shrimp, respectively (all shrimp have six segments). Often graded as small, medium and large, though no standards exist.

Frozen Shrimp Packs

Blocks: Typically, green headless shrimp. Blocks offer easy storage and the versatility afforded by a basic raw product. But separating out a portion of the block can be a challenge, and labor is required to peel and devein the shrimp. Shrimp blocks come in one of two styles:

  • Layerpack. (Also “finger pack.”) Meticulously handpacked shrimp, frozen in a neat pattern and doubleglazed. 
  • Random. (Also “jumble” or “shovel” pack.) These may have some order, but shrimp are not evenly glazed.

IQF: Individually quick-frozen, most common with PUD and P&D shrimp. IQF packs may be less convenient than blocks to store, but they offer savings in labor and allow the user to remove the quantity needed and return the unused portion to the freezer. 

Glaze is necessary to properly freeze shrimp. Both shrimp blocks and IQF shrimp are glazed with a protective ice coating to prevent dehydration. 

Blocks are packed in polyethylene wraps inside cartons, which are then filled with water inside the polyethylene film, so the block is completely encased in water before it is frozen. 

IQF shrimp is first frozen, then passed through a drip or spray of water to coat each piece, then re-frozen. This may be done several times to build up sufficient protection.

Checklist

  • Shrimp should be of uniform color, size and condition. Mixed colors could indicate mixed species or decomposed product. 
  • Shrimp should smell like fresh seaweed or seawater. Hydrogen sulfide (rotten egg) or ammonia smells indicate decomposition. 
  • Melanosis, or black spot, is natural deterioration of shell and meat but indicates poor quality. 
  • A shrimp with fewer than five whole tail segments should be graded as a piece. 
  • Check breaded shrimp for “halos,” fringes of excess batter and breading; breading lumps; or voids in the coating. 
  • There should be no extraneous material, like flippers, antennae, shell fragments or legs. 
  • Grade A shrimp has “good flavor and odor.” Grade B has “reasonably good flavor and odor.” Grade C has “minimum acceptable flavor and odor with moderate storage-induced flavor or odor.”