We get this question quite often: "My meat has green [or, blue] spots on it. Is it mold?" No. It's ink.
So, the natural question is: Who's been marking on my meat? It's the government. Not the farmer.
First of all, molds that grow green and blue, like you might find in your refrigerator, dine on decaying plants. It's rare to find a mold of green or blue "fuzz" that grows on meat products.
What many people don't realize is that when meat is slaughtered in the U.S. for human consumption it has to be marked for inspection. We've all seen the mark -- a little round insignia that reads "USDA Inspected and Passed" with an establishment number identifying the butcher. It's on the labels of any meat you buy. Other times, in lieu of the USDA round stamp, you will see a state-shaped insignia, which indicates that the state's inspectors approved the meat for sale inside the state's borders, but not across state lines.
In either case, it's a stamp of approval on the meat package. But did you know that, as soon as an animal is slaughtered, that same stamp of approval is applied directly to the carcass? Yes, edible ink, harmless to the consumer, is stamped right on the meat as the carcass hangs at the butcher.
Why? Well, in many cases, the place where the carcass is slaughtered might not be the same facility where it's processed further into steaks, bacon, sausage, or burgers. In order to put the mark of inspection on the package, where we are all used to seeing it, the butchers who make those packages have to know that the meat came from an inspected carcass. And, for that, they need to see that ink on the meat.
Most of us never see the ink, and with reason. Inspectors try to put it on a portion of the carcass that won't be sold whole to a consumer -- like a slab of fat or a tough ligament fiber. But sometimes, they miss. Or sometimes, a butcher is resourceful and wastes nothing. It's most commonly seen on bacon (because that comes directly from the pork's side), in shoulder roasts, (because that's near where the stamps are applied), or sometimes in sausages (because that fat was ground into the patty).
It's perfectly safe to eat. It's actually just a vegetable-based dye, commonly made from color-rich roots or berries, and fully edible.
So, the next time you find a green or blue speck on your farm-fresh meat, don't toss it out. You're just seeing the evidence that the meat was inspected, and passed.