They do not dye hamburger meat.
Hamburger meat is not dyed using food coloring or any other food additive.
The U.S. Department of Agriculture inspects all ground beef and food coloring is not allowed to be added to the beef.
However meat such as hamburger meat or ground beef and other meats are treated and injected with carbon monoxide to keep it from turning grey.
Once meat is exposed to air, it gradually turns from red to a not-so-festive brown or grey color.
While grocery stores put new meat out each day, some packages sit on the shelves for many days.
To keep the meat looking appetizing, they treat it with Carbon Monoxide.
What color is meat naturally?
Myoglobin has three natural colors depending on its exposure to oxygen and the chemical state of the iron.
If no oxygen is present, the meat appears purple red, like in vacuum packaged meat, and is in the deoxymyoglobin state.
Meat is bright red when exposed to air and is typical of meat in retail display.