I was reading somewhere a few days ago about a little battle going on with the FDA involving the packaging of meat. The topic at hand is the treatment of fresh meat with carbon monoxide to keep the meat looking the usual blood-red color that we so often associate to ground beef and the like. The argument is that if the meat is constantly blood- or dark-red, people won’t know the meat is bad.
This is a bit of a misnomer. With that being said, I do not want to eat meat that has been sprayed down with carbon monoxide.
So let Mr. Michael explain what happens exactly to meat. The meat you see in the store is typically a nice red color, but sometimes it looks … eh … a little less than fresh. So how do you know exactly how fresh the meat is? Color is one indication, but so is packaging and the amount of light the meat is exposed to.
Meat (muscle tissue) has myoglobin attached to it, which provides meat the usual color. The age of the animal, the amount of exercise the animal gets, or even the sex of the animal can determine that amount of myoglobin in the muscle tissue. The more myoglobin, the darker the color. Myoglobin is typically a dark red – purple in color.
Once myoglobin is exposed to oxygen, it becomes oxymyglobin and the color changes to an almost cherry red. That is the typical color you see in the grocery stores because the meat has already been exposed to oxygen. That is also why sometimes you cut open a piece of raw meat and it’s grayish-brown inside — because it’s not been exposed to a significant amount of oxygen. This obviously does not mean the meat is bad. Additionally — if meat is vacuum packed, it has minimal oxygen exposure, therefore resulting in gray-brown meat. However — when you’re in the grocery store, and you see regularly packaged (wrapped meat) that is browning … it’s probably a bit old. Oxygen still gets through that wrapping, and you get an over-exposure of oxygen, resulting in metmyoglobin which is a brownish-red color.
So there you go — the mystery of meat color, solved and explained so you can make smart choices when you eat your cows and pigs.