Sour, rancid, or ammonia-like smell
Slimy, sticky, or tacky texture
Green, gray, or brown discoloration
Mold growth
Packaging is swollen, leaking, or damaged
Beef feels unusually soft or mushy
Off or unpleasant odor after cooking
Past the use-by or expiration date
Left unrefrigerated for more than 2 hours
Left in temperatures above 40°F for too long
Signs of freezer burn with severe drying or discoloration
Unusual gas release when opening sealed packaging