After Googling the word Pink Slime this is two articles I found .
"Pink slime" is a meat by-product used as a food additive to ground beef and beef-based processed meats, as a filler, or to reduce the overall fat content of ground beef. In the production process, heat and centrifuges remove fat from the meat in beef trimmings. The resulting paste is exposed to ammonia gas or citric acid to kill bacteria. In 2001, the United States Department of Agriculture approved the product for limited human consumption. Lean finely textured beef" (LFTB prepared using ammonia gas is banned for human consumption in the European Union.
2.“Pink slime” (ammoniated boneless lean beef trimmings) is the nickname earned by a formerly inedible byproduct of the beef industry. Once used in pet food, it’s now a cheap additive in ground beef. Pink Slime is an additive that the federal government has approved to be mixed in with ground beef.
Please, please GRIND YOUR OWN the United States Department of Agriculture ( USDA ) does not seem to care what the general public eats.