An Orthodox Magisterium?

Recently I listened to a podcast in which Larry Chapp (a universalist Roman Catholic) interviewed Dr. David Bentley Hart. In the course of the interview Dr. Hart asserted that, unlike Roman Catholicism, Orthodoxy does not have an official and authoritative Magisterium. By this he meant that Orthodoxy possesses no institutional organ (such as the papacy and the episcopate dependent upon it) that can routinely and authoritatively declare what is or is not the official teaching of the Church when consulted.