One of the great food fads of the 1980s, fajitas, brought widespread acclaim to Tex-Mex restaurants, but this novelty was simply the traditional Mexican method of preparing beef. Hispanic carne asada, thin cuts of freshly slaughtered meat cooked briefly on a hot grill, differed dramatically from thick Anglo-American steaks and roasts, which were aged to tenderize the meat. When investors sought to import the Chicago model of centralized meatpacking...