Sour or unpleasant smell
Visible mold on the surface or around the lid
Pink, green, blue, or black discoloration
Watery liquid with clumps that looks unusual
Off taste that is bitter, rancid, or overly sharp
Bulging, leaking, or damaged container
Expired date plus signs of spoilage
Fizzing, bubbling, or gas release when opened
Texture that is slimy, curdled, or unusually lumpy
Any sign of contamination from a dirty spoon or container