After cooking a beef bottom round rump roast, a red coloring is covering, and penetrating, the meat.
The roast was purchased at a reputable grocery chain and properly refrigerated for two days before use. The raw meat appeared normal, was placed in a seasoned, 10-year-old, cast-iron pan, and cooked four hours au jus.
When the cooked roast was cut, the inside of the meat was the correct color and smelled appropriately. However, covering the outside was a strange red coloring penetrating 1/2" into the entire roast; top, sides, and bottom. The coloring did not affect the flavor. Could someone please tell me what this coloring is? I have never experienced anything like this in my 50 years in the kitchen.