Ground beef is a weeknight workhorse. If you have a pound of ground beef you’re well on your way to hamburger mac, a juicy burger, or ground beef bulgogi. But what if you grab the ground beef from the fridge or freezer and it’s already brown? Is dinner doomed? In a nutshell, the answer is…maybe. Let us explain.
Why Does Ground Beef Turn Brown?
Freshly cut meat is a purplish or burgundy color, but that changes quickly. “Oxygen reacts with myoglobin (a protein found in muscles), causing the meat to darken,” says Brittany Towers, the food scientist behind The Black Food Scientist. After about 15 minutes of exposure to the air, the meat turns the bright red color we’re familiar seeing in the butcher case. After about 5 days in the fridge, the outside will turn brown.
But what about raw ground beef that’s red on the outside and brownish in the center? Let’s revisit our friend myoglobin. Myoglobin has three color states: purple, red, and brown. We touched on how the brown state can occur after prolonged storage, but that color shift can also be caused when the meat is exposed to small amounts of oxygen, like the environment in the center of your package of ground beef or when pre-made burger patties are stacked on top of each other.
So Can I Cook It?
To figure out if raw ground beef is safe to eat, use all of your senses—as well as your common sense. “As long as ground beef isn’t slimy or doesn’t smell bad the color doesn’t matter,” says Towers.
To keep ground beef at its freshest, use it within a day or two of buying it or stash it in a zip-top freezer bag, mark the outside of the bag with the date, and freeze the meat for up to 4 months. Thaw ground beef in the fridge before cooking.
The whole myoglobin conversation is also a good reminder that the safest way to know when meat is cooked to temperature is to use an instant-read thermometer. If your ground beef is brown before cooking, visuals alone won’t tell you when it’s cooked properly. The USDA recommends cooking ground beef to 160°F.