Whiskey sour: should the bourbon kill any germs in the egg whites?

The alcohol is not enough to kill germs in your beverage. Typically alcohol content necessary for killing germs is between 60% and 95%.

Straight bourbon will not approach that.

You're "not dead yet" because the food supply is generally very safe, though consuming truly raw eggs is counter to FDA and USDA recommendations.

A recommendation compliant alternative to raw eggs is to use pasteurized eggs, which in my experience work just fine in cocktails.

Its kind of interesting as these questions actually relate to one another.

Question A: Will bourbon kill the germs in egg whites?

In short, kind-of, sort-of. Alcohol will inherently deprive germs of the oxygen/hydrogen that they need to survive and reproduce, but the most effective disinfectants contain at least 60% alcohol. A far cry from your typical 70 proof bourbon (35% alcohol). That being said, any portion of the egg white that comes in contact with the bourbon (assuming 1 shot bourbon to 1 egg white) will have the germs drastically inhibited, just like you after a few whiskey sours!

Question 2: Am I getting the protein from the egg white.

This answer is easy. Yes. In the same way that the lime in ceviche does not kill the protein in the shrimp, whiskey, which is inherently acidic, does not destroy the protein in the egg.

But this is where it gets interesting, and, as far as I know, we are outside the world of observed science (at least a little bit).

Being an acid, whiskey would break apart the molecular structure of the egg proteins. This is what happens when you marinade the bird is brine, or cook the shrimp in ceviche, we are breaking apart the surface level of proteins to allow the brine/marinade to work its way into the meat. Also, being an astringent, the whiskey also deprives the germs in the egg of their necessary resources. Though I do not know if any studies on whiskey vs egg has been done, in theory, the acids in the whiskey should break down the egg while also disinfecting anything found inside the egg at the same time. In function, it should function like washing your hands in soap whilst dousing them in isopropyl.

If anyone knows of a study on alcohol on loose proteins, please let me know!

That being said, if you are enjoying your whiskey sours in the USA, Britain, Germany, or practically any northern European country, there is no reason to worry about getting anything from an egg white. I'd be more worried about the hangover.