Most likely, no! What you are seeing is probably the micro-roots that become visible when the sprouts are dry. These feathery roots help with drawing in water and they will disappear after rinsing. Here's what they look like (taken 12 hours after rinsing): Whatever the sprouts look like—the smell test rarely lies! So make sure to smell the sprouts. If it's a bit off, don't risk it and start a new batch. In case this is your first time ever coming close to sprouts, note that the bitter smell is normal. If still in doubt, see this post for a comparison between feathery sprout micro-roots and actual mold.