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.