A radish should be fresh, bright looking, smooth, firm, well formed, tender, crisp of color characteristic of the stated variety and a reasonably mild flavor.  If the tops are attached, they should be fresh, bright, and green.  Radishes that are wilted, spongy, dry-looking, rough-skinned, cut or broken are undesirable.  Sponginess and pithiness can be detected by applying pressure to the radish with the fingers.