You are right about the postive contamination of milk - Iodine used to be used to clean the lines the milk went through but now it isn't. So there used to be a bit getting into the milk itself and once upon a time every Australian school child got their milk at lunch times. There are few salt products on the market that contain iodine. If you go into any supermarket, there are only 1, maybe 2 packets that contain iodine these days.