

Is this mould on the clothes under my bed?
For context I live in a flat in the UK which is very old and has bad circulation of air, i recently left it for a couple days and came back to mould all over a number of wooden objects in the living room, but none in other rooms. I have a dehumidifier running constantly in my room.
This drawer under my bed is right next to the dehumidifier, but every bit of clothing in there has this weird yellow stuff on it, nothing else in the room is mouldy or damp. Those clothes were dry when they were put in there. Is it mould?