Vacuum the couch to remove all dirt and debris. Remove the couch cushions if possible and vacuum all cracks and crevices. Food or debris sitting in the crevices may have caused the foul odor.
Blot any wet stains with paper towels to absorb the liquid. Avoid rubbing the wet stains because you can spread the stain.
Fill a spray bottle halfway full of white distilled vinegar. Pour cool water into the bottle to fill it.
Spray the entire couch with light mists. Allow the surface to air dry. Repeat spraying the furniture with the vinegar until you remove the odor.
Dampen a sponge with the white vinegar and blot it over any stains that are emitting an odor on the couch. Allow the area to dry and repeat until you remove the odor.