what were the swindles that took place on the meat packing industry in Chicago?

The industry sells spoiled meat by filling it with pickling chemicals to rid it of rotten smells. Bones from rotten ham are replaced with a hot iron. They label all meat as their finest meat. There used to be three qualities of mean but now they label all meat, even rotten pieces, as the best quality. Dead rats, who died from poison, end up in piles of meat and are processed with the meat.