Is there a reliable way to distinguish a consecrated host from a non-consecrated host?
No. This is because the physical accidents remain. It is discerned solely by the faith of the observer.
If it is in the tabernacle, in a monstrance or being distrubed at communion time, it is probably consecrated. If it is in a bag or plastic container in an unlocked drawer in the sacristy, it is probably not consecrated.
When in doubt, it is best to assume the host is consecrated.
I realize this probably doesn’t really respond to what you are asking, so to that point, there is no way by appearance to discern a difference.
But this is an important point. Since it is not possible to tell from outside appearances which hosts are consecrated and which are not, there must be procedures and practices to make sure they do not get mixed up.
Yes, of course there are procedures and practices to make sure that the consecrated hosts and those not consecrated do not get mixed up. The consecrated ones are placed in the tabernacle after Holy Communion has been distributed, and before the end of Mass.
All unconsecrated hosts, other than those intended for consecration at Mass, are kept in the sacristy. There is usually no danger of them getting mixed up.