I don't remember quite how many, but no need to drastically overestimate. Go for just a wee bit over what you think based on usage at home. You can buy extras onsite and, while expensive, it's not like you're planning to buy your whole supply that way. A few good options for bringing them if you're flying:
1) pack diapers, wipes, bottles and other consumables in a separate bag that becomes your souvenir purchases bag because it will be empty by the time you're done.
2) ship a box with all your consumables in it to be waiting for you upon arrival so you don't have to fly with it
3) place an order with garden grocer for delivery to your r hotel for baby needs plus bottled water, sodas, breakfast items
On the germ problem - don't worry too much! The big problem comes from us touching everything, which a 10 week old won't do. Just wash YOUR hands a ton. Have fun!!