Black Mold After Flooding

My husband and I used to live in an upstairs apartment of a house before we were evacuated due to flooding. Water reached half way up the first floor and left what looks to be black mold on the walls of the stairwell leading up to our front door. There is no visible mold in our actual apartment, but I have been told our things are still affected by it. Should we plan on having to get rid of most of our belongings? I assume upholstered items are ruined, but what about wood furniture and things like that? Thanks!