milk is a main source of baby nutrition but it is still a bodily fluid capable of transmitting disease?

Ignoring your irrational wish for me to feed my baby in a bathroom (gross). milk, while not sterile, doesn't actually carry bacteria that you need to worry about. Also feeding is usually a very clean and tidy process, unlike bottles that can be set down and knocked over to spill. I have waited tables for many years and could tell some really gross stories about table cleanliness, so if you are really worried about germs, than bring Clorox wipes with you and wipe down everything before you touch it. I can pretty much guarantee that milk would be the least offensive body fluid that you will come in contact with at a restaurant.