Sour, rotten, or ammonia-like smell
Slimy or sticky texture
Gray, green, or dull brown discoloration
Mold growth
Package is swollen, leaking, or damaged
Bacon feels unusually tacky or dry and hard
Off or rancid taste
Past the use-by or expiration date
Stored improperly or left out too long
Unusual gas buildup when package is opened