I recently read that Kroger has decided to stop using CO (carbon monoxide) to give meat that deceptively fresh look.

It seems backwards that ground beef should look pink and fresh on the outside and not quite so pink and fresh on the inside. After all the outside is exposed to the air. If you've ever had the butcher run meat through the grinder (or ground your own) you'd see that in the ordinary course of things, it is the outside, not the inside that turns brown.