I think you get better results treating your fabrics before sewing than after. Old timey fixatives include salt and vinegar in your wash. Another old time fix is heat -- boiling (in a pot or microwave) but obviously that is with yardage and not finished products. You can also use Rit colorstay, but again, I'd be doing it in my prewash and not in my regular wash.
Color safe "dry" bleach may be better than regular bleach, but it has a hard impact on fabric.