Mustard seeds are the edible seeds of the mustard plant. As of 2014, both Canada and the United States produce a large share of the world's mustard supply.
Until the advent of World War II, most mustard was produced in Europe. North American farmers began growing mustard when supplies from Europe were interrupted due to the war.
Mustard seeds that are commercially harvested, packaged and sold can come from black, brown or white mustard plants. They are used as a spice in soups, salads, marinade, barbecue rubs and breading. Mustard seeds can also be ground up to create the popular condiment known as mustard, a culinary tradition that traces back to the early Romans.