Tried parazone almost same as Milton and blew it through the hose and nozzles but its no better.
I'm afraid it might melt in the dishwasher so I don't know what next, a mask maybe. ...
There's stuff called Puriclean,it's for cleaning water lines in Caravans/Holiday homes that have been idle for a while,Absolutely brilliant for that situation. You'll get it in any camping or caravan supplies store,O Mearas Camping etc....
Windscreen washer bottles account for 20% of all Legionaires Decease infections. (go Google it's scarry)
After living abroad learned to always throw a couple of drops of Milton or other desinfectant in when refilling... (not needed with the winter kind that has alcohol based anti-freeze)