IME I have never managed to get mould out, but I do have limited experience. At hottest temp, I don't think they'll continue to multiple but they may well have stained already. I betcha there's a clever chemical cleaning solution to getting rid though... Have you googled?
Apparently leaving them out in the sun ( ha! what sun?) helps to kill the mould. I also found rubbing Milton fluid on the inner lining of a cool-bag removed stains caused by mould but obviously you couldn't do that with a coloured fabric unless you love the tie-dye look!