Back in the early 2000's, an acquaintance of my son's got a job at Taco Bell...she stated the boxes of beef were stamped "USDA GRADE D, but edible for human consumption..."
Grade D....hmmmm
One of the C Ration main courses was "Pork Slices in Own Juices".
The ingredients included lymph nodes, pancreases, main arteries and snouts IIRC......