How do you know when a doll has mold?

I apologize since this is probably a frequently asked question and I'm probably just being paranoid but I just came across someone who found mold on a new in box doll, and it's the same doll I just ordered on line and I can't help but start to worry about my doll that's coming and the dolls I currently have. I'm scared of the possibility that some of my dolls have mold and I just don't know it, I don't have any reason to believe that yet, again I'm just paranoid. I haven't taken any of their clothes yet off but I've been smelling them because I heard it often smells, but then I get more worried because I've had mold growing on my bathroom walls before and I never noticed any smell 😭. Sorry for this panic written paragraph but I just really love my dolls and don't want anything bad to happen to them. If you ever had this happen to you, was it noticable immediately?? Or did you not see any mold untill later. Also is there any cleaning we as collectors should do to avoid it happening in the future?