Cast iron meat grinder; first time used had black stuff in it
If you did not clean and run an initial process through the grinder before using it for the first time, I recommend discarding the meat.

When the machine was packaged, oil was probably used to prevent sticking or corrosion during storage. Also, chemical residues from protectants and finishes may still be present in the machine. Before the first use, it is best to thoroughly clean the device and to put through a generous portion of raw meat fat to "sweep out" metal dust and filings and to clean up excess lubricant. Discard the raw meat fat where no animals will be able to scavenge it.