The pork loin is a primary cut of the pig -- a large section of the animal that supplies a variety of retail cuts, including loin roasts, chops and the tenderloin.
A pig yields two loins, each running adjacent to the spine from the shoulder blade to the leg. The tenderloin, a long, tapering muscle, lies against the inside of the ribs toward the center and sirloin, or lower end, of each loin. The loin muscles get little use, resulting in tender meat -- this is especially true of the tenderloin, which constitutes the most tender cut of pork.
Regardless of whether a loin comes from commercially raised pork, bred to be extremely lean, or from heritage pork, purposely raised to provide fattier meat, the inherent leanness and lack of connective tissue in the loin dictate cooks use dry-heat cooking methods for the best results. Roasting or grilling, for example, ensures cuts from the loin stay moist and tender, as long as the meat is not overcooked.
Although pork poses less of a risk for trichinosis today, cooks should aim to cook pork at a temperature sufficient to destroy any traces of trichinae and other micro-organisms, but not so high as to dry out the meat. "The Joy of Cooking" suggests 150 degrees Fahrenheit as a sufficiently high internal temperature for pork loin, whereas the USDA recommends a more conservative 160 degrees Fahrenheit.