Netherlands–based Bejo Zaden has U.S. approval to change the genetic code of radicchio. The plant has been altered to sterilize the male version of the plant and make it tolerant to a herbicide. Since 1992, the United States has allowed food producers to change the DNA of plants humans consume. The changes make them able to withstand specific growing and transportation risks. Some are changed to ripen slower. Some European countries ban genetic alterations to the human food supply.