I'd say it's mostly safe since from my experience, I haven't had an issue yet but I'm extra cautious like leaving it in a tightly closed bag in the car (or outside) for a few days in case of bed bugs and then I do a hot wash and dry it on high heat at a public laundry mat. A lot of my reliable clothes and shoes came from thrift shops and whatnot and they last quite a while due to how they're older and therefore better quality than today's fast-fashion clothes. So as a tip, inspect it first for good quality material and how it was sewn and look at the style like if it's retro/vintage type and compare store locations (like at a rich area of the town)
For shoes it was slightly different in that I would either use a sanitizing spray and leave it in a bag to fumigate for a while or give it a mild bleach wipe-down and leave it outside to dry (just gotta be careful like for instance with one pair of shoes, the glue dissolved but no big deal, just had to re-glue the fabric back onto the sole)
But this is why when I donate, I make sure the clothes are clean first before donation just to be courteous. It also makes me glad to live in a dry region where I don't have to worry about mold that much as oppose to more humid areas with mold problems (like Houston, esp. after the floods causing mold overgrowth)