A kitchen utensil that serves as a tool to remove the intestinal black vein when preparing either cooked or raw Shrimp is a Shrimp deveiner. As a knife, the deveiner allows the lower portion that is ridged to strip out the vein, while the upper beveled knife edge serves to cut the shell as it moves from the head down to the tail of the shrimp. Typically, whether veins are in or out, seldom is there a flavor difference unless the vein is large and contains a higher volume of grit and digested material. It is removed more for the appearance than taste. Some cooks preparing Shrimp also remove the thin line of material that runs along the belly section of the shrimp, referred to as the ventral nerve cord that controls the movement of belly muscles. However, this cord is seldom removed and is not harmful to be consumed.
When buying Shrimp, most packages are marked with the "count" or number of Shrimp per pound in the package. However, the number is a range, so when inspecting the package a set of numbers separated by a slash, such as 21/25 indicates there will be 21 to 25 shrimp totaling a pound in the package. As can be expected, larger Shrimp will have a lower number per package while smaller sized Shrimp have a higher number per pound, such as 51/60 per package. For recipes, a guide to follow on the number of Shrimp per pound is as follows:
USDA Nutrition Facts