Many cocktails such as fizzes call for an egg white (or an egg yolk in some cases).
Given that I'm not sure I would eat a raw egg, how safe is it to put one in my drink? Are there any alternatives I can use instead of egg white?
According to a USDA report, a study done in 2000 showed that of the estimated 47 billion eggs consumed in the U.S. annually, 2.3 million of them were estimated to be contaminated by salmonella, leading to approximately 240,000 illnesses. So, if my math is correct, for any given egg, you have something like a 1 in 100,000 chance of getting one that has salmonella, and the chance of getting ill is somewhat less that that...Somewhere between 1 in 100,000 and 1 in a million.
So, relatively low risk, I'd say, assuming that the global numbers are at least on the same order of magnitude as what we see in the U.S.
That said, there is a way to reduce the risk even further...Nearly to zero. That is to use pasteurized eggs. Most shell eggs sold in the U.S. are unpasteurized, but you can find pasteurized shell eggs, and the pasteurization process does quite a good job of killing salmonella, and so these eggs are highly recommended in any concoction that requires raw, or undercooked eggs.
Whites and yokes are also used in many health drinks. Raw eggs (not expired) are considered safe (and healthy).
It is highly dependent on where you are located and your risk tolerance (do you eat sushi, rare beef, etc?). As someone who has had salmonellosis, I can verify that you really, really do not want to contract it. Really.
That said, in the US you are probably OK, elsewhere likely somewhat less so (relative risk is probably roughly an order of magnitude greater in Western Europe, and likely still greater elsewhere). This is thoroughly set out in Athanasius's great answer on our Cooking sister site.
I would not rely on the alcohol content of the fizz to vitiate the risk in a material way: microbicidal potency of alcohol at concentrations below 50% is pretty negligible (source)... so if the reason you wouldn't eat an egg raw is the risk of gastroenteritis (and not some ick factor), then I'd consider the risks the same.
Aquafaba could be something to think about. Here's a quick overview:
The water that is left after boiling beans or chickpeas is full of proteins and starches etc... If whisked like egg white it produces what can only be described as meringue. I believe that you could add your cocktail to this, whisk it all up and there you have it.
You can either boil your own beans/chickpeas, or buy a jar/tin, drain (use chickpeas for other things: humus or curry or something) put the water (aquafaba) in a bowl and whisk (it will take a little time so an electric whisk is best). The guys at aquafaba know more than me about it's uses, here's the website, and they also have a Facebook page.
I have not tried making cocktils with aquafaba, but have made meringues from it and it does work.
There is no need to cook aquafaba as it is already cooked (no salmonella risk)- it's just a by-product and is suitable for both vegetarians and vegans.