How to Tell If Ground Beef Is Bad (and Why Gray Is Often Fine)

Ground beef has gone bad if it has a sour or rotten smell, a sticky or slimy surface, or mold, or if the whole package has turned gray or brown. A gray center with a red surface is usually just a normal color change from lack of oxygen, not spoilage. And because the bacteria that cause food poisoning don't change how meat looks or smells, store it properly and cook it to 160°F either way.

Here's how to read the color, smell and texture of ground beef, plus how long it actually keeps.

Why ground beef turns gray

Meat color comes from a protein called myoglobin. When it's exposed to oxygen, it forms a bright cherry-red pigment, which is why the surface of a package of ground beef looks red. The beef in the middle of the package gets much less oxygen, so it can stay a duller grayish-brown. USDA's ground beef guidance explains that this interior color is normal.

A few other color quirks are also normal:

• Vacuum-packed beef looks purplish or burgundy. It usually brightens to red within about 15 minutes of being exposed to air.
• Beef can darken over several days in the fridge as the pigment changes. Brown on its own isn't proof of spoilage, but it's a sign the beef is getting older.

The warning sign is when all the beef in the package, outside included, has turned gray or brown, especially along with an off smell or tacky feel.

Signs ground beef has gone bad

• Sour, rotten or ammonia-like smell. Fresh ground beef smells mild and meaty. Trust your nose; an off smell is the clearest sign.
• Sticky, tacky or slimy texture. Fresh beef feels cool and slightly damp. A slick or tacky surface means spoilage bacteria have taken hold.
• Gray or brown throughout, including the outside, particularly combined with an odor.
• Mold of any color. Throw it out.
• Bloated or leaking packaging, which can signal bacterial growth.
• It's been in the fridge too long, more than 1 to 2 days after you bought it, even if it looks fine.

Why looks and smell aren't enough

There are two kinds of bacteria to think about. Spoilage bacteria cause the smells and slime you can detect, but they generally don't make you sick. Pathogenic bacteria, such as E. coli O157:H7 and Salmonella, are the ones that cause food poisoning, and they don't change the look, smell or feel of meat. Grinding can spread any bacteria from the surface throughout the beef, which is why ground beef needs more care than a whole steak.

So the rule is simple: if it smells or feels wrong, throw it out. If it seems fine, still follow storage times and cook it to a safe temperature. When in doubt, throw it out.

How long does ground beef last?

• Raw, in the fridge (40°F or below): cook or freeze within 1 to 2 days of buying it.
• Raw, in the freezer (0°F): safe indefinitely, but use within about 4 months for best quality. See how to freeze burger patties.
• Thawed in the fridge: cook within 1 to 2 days.
• Cooked burgers and leftovers: refrigerate within 2 hours (1 hour above 90°F) and eat within 3 to 4 days, per USDA's leftovers guidance. Reheat to 165°F; see how to reheat a burger.

What sell-by and use-by dates mean

A "sell-by" date tells the store how long to display the product. It isn't a safety date, and USDA notes that package dates aren't an indicator of safety. For ground beef, go by when you bought it and how you've stored it: cook or freeze it within 1 to 2 days of purchase, even if the sell-by date is later. If a "use-by" or "freeze-by" date is printed, follow it for best quality.

How to buy and store ground beef

1. Shop for it last. Pick up meat at the end of your trip and get it home and into the fridge quickly.
2. Check the package. Choose cold, intact packages that aren't torn or leaking.
3. Keep it cold. Your fridge should be at 40°F or below and your freezer at 0°F.
4. Prevent drips. Store raw beef on a plate or in a bag on the bottom shelf.
5. Freeze what you won't use within a day or two, in airtight packaging labeled with the date.
6. Thaw safely, in the fridge, in cold water or in the microwave, never on the counter.

Cook it to 160°F

Cooking ground beef to an internal temperature of 160°F (71°C) kills harmful bacteria. Color isn't a reliable test; USDA has found that burgers can brown before reaching a safe temperature. Check with an instant-read thermometer, inserted into the side of the patty. Our burger temperature and doneness guide has the details, and how to make juicy burgers shows how to keep a fully cooked patty moist.

Choosing beef in the first place? Read how to choose the best ground beef for burgers.

FAQ

Is gray ground beef safe to eat?

If only the inside is gray and the beef smells and feels normal and is within its storage time, it's usually fine. Gray or brown all the way through, especially with an odor, means throw it out.

Does cooking bad ground beef make it safe?

Don't try. Cooking kills bacteria, but beef that smells or feels spoiled should be thrown out, not salvaged.

Can I eat ground beef a few days past the sell-by date?

The sell-by date isn't a safety date. What matters is that you cook or freeze raw ground beef within 1 to 2 days of buying it and keep it at 40°F or below.

Why does vacuum-packed ground beef look purple?

Without oxygen, the meat's pigment stays purplish-red. It should turn bright red within about 15 minutes after the package is opened.