Sour, rancid, or “off” smell
Bitter, metallic, or stale taste
Mold growth
Discoloration or dark spots
Slimy, sticky, or unusually soft texture
Strong yellowing or separation from normal appearance
Visible water droplets or unusual moisture
Packaging is swollen, leaking, or damaged
Past expiration date and stored improperly
Tastes fine at first but leaves an unpleasant aftertaste