This Is What's Really br Inside Your Hot Dog Every time you bite br into a juicy hotdog, you might find yourself br pushing its potential contents br to the back of your mind. But if you'd like to know br what you're eating, br here's the lowdown. No matter if your hot dog br is made of beef, pork or chicken, br they all start with "trimmings." This is a more pleasant term for leftover meat cuts such as fatty tissue, sinewy muscle, head meat and sometimes liver. "Trimmings" can also br include blood, skin and feet,br and it's all USDA-approved. Once combined, the gristle is br pre-cooked to kill bacteria br and formed into a paste. At this point, any number of additives could be introduced. The meat paste is then pumped br into casings to attain its shape. Then the franks are rinsed, the br casing is removed, and they br are ready for consumption. If you'd like to stick with muscle tissue instead br of organs, feet and blood, opt for hot dogs labeled br "all beef" or "all pork.