With reference to blowing under the dressed pizza skin to help release it from the peal, it has more to do with perception than food safety. How would you feel if you were at a restaurant where some snotty nosed kid was blowing, or coughing on your pizza? Don't worry, it will be sterilized in the oven. You might have a hard time selling that to your customers whose only comment might be "GROSS!". Then too, there might be a hard sell to your health department inspector. One old trick that I've used with very soft doughs is to open the dough into a pizza skin and place it onto a pizza screen for dressing, I then put the dressed skin (still on the screen) in the oven to bake for a couple minutes, then slip a peal under the now forming crust, remove the screen and continue baking on the stone. This is similar to a procedure called "decking" the pizza, but when decking the pizza, it is typically removed from the screen and placed on the stone/deck during the last couple minutes of baking to achieve a crispier crust than can be had by baking only on the screen.
Tom Lehmann/The Dough Doctor