I recently noticed some bright blue, almost cyan colored spots on some unrendered pork lard. I thought it was some kind of mold and it was all throughout, so I tossed it. I felt kind of dumb because the farmer called me maybe 30 minutes afterwards and explained it was probably a meat stamp. I got it pretty cheap though and was tired of dealing with it. But I learned something and am sharing this.
I did some internet searching and it seems that butchers will place a food grade stamp on meat cuts. Sometimes they don't take it off and you will have blue or purple spots in the meat from the dye. The dye is supposedly made of beets, but some brands keep it a "trade secret". The farmer said the spots in mine were most likely one of these stamps. So if you have alarming bright blue or purple spots, maybe give it a little more thought than it being mold and tossing it out.
I did some internet searching and it seems that butchers will place a food grade stamp on meat cuts. Sometimes they don't take it off and you will have blue or purple spots in the meat from the dye. The dye is supposedly made of beets, but some brands keep it a "trade secret". The farmer said the spots in mine were most likely one of these stamps. So if you have alarming bright blue or purple spots, maybe give it a little more thought than it being mold and tossing it out.