Grinding meat changes the safety situation.

When beef is ground, bacteria that may have been present on the surface can become distributed throughout the meat.

That means bacteria aren’t necessarily limited to the outside.

For this reason, ground beef needs to be cooked thoroughly rather than simply browned on the surface.

The recommended minimum internal temperature for ground beef is:

160°F (71°C).

A food thermometer is the best way to verify this.

Don’t Judge Cooked Ground Beef by Color

Another common mistake is assuming that brown meat is automatically safe.

It isn’t.

Ground beef can turn brown before reaching a temperature sufficient to destroy harmful bacteria.

Likewise, properly cooked ground beef can sometimes retain some pink color.

Therefore:

Brown does not automatically mean safe.

Pink does not automatically mean unsafe.

The internal temperature is much more reliable than color. (Ask USDA)

What Should You Do With the Meat in the Picture?

Based on the photograph alone, the gray center appears consistent with the normal effect of limited oxygen inside a tightly packed block of ground beef.

So the gray center by itself is not enough reason to conclude that the meat is spoiled. (Ask USDA)

But a photograph cannot tell us how the meat was stored.

Before cooking, consider:

Was it refrigerated properly?

Ground beef should be kept at or below about 40°F (4°C).

How long has it been refrigerated?

USDA guidance recommends using refrigerated ground beef within about 2 days, or freezing it if it won’t be used during that period. (Ask USDA)

Is the packaging intact?

Avoid meat from packaging that is leaking, badly damaged, or appears compromised.

Does the texture seem normal?

A slimy or unusually sticky surface is a warning sign.

Does it have an unpleasant smell?

A strong abnormal odor can indicate spoilage.

If the meat was properly refrigerated, is within the recommended storage period, has normal texture and odor, and the only unusual feature is the gray center, the color difference may simply be due to oxygen.

What If the Whole Package Is Gray?

That’s a different situation.

If the entire package has become gray or brown rather than just the center, especially if the meat also smells unpleasant or feels sticky, don’t assume the color is simply caused by lack of oxygen.

The USDA notes that when all the meat in a package has turned gray or brown, it may be beginning to spoil. (Ask USDA)

When several warning signs occur together, it is safer to discard the meat rather than trying to rescue it by cooking.