IMO - I am not a lawyer - this is clearly and trivially fair use. (I would change the beer can more, though.) Problem is, as mentioned above, fair use does not in itself protect you from trouble. But I'll take a slightly softer line in that you're not likely to get on anybody's radar in the first place, or merit more than a C&D if you do. In which case, just change them then. As a strictly creative note, I'd suggest making original designs unless parodying existing drinks is specifically necessary or useful to what you're doing.

Signed, Alfred E. Neuman

As long as you poke fun at the product, you can use names with similar likeness to original product under fair use of parody.

Even if you reproduce the labels exactly (e.g. using photographs of the real products), it technically should be legal. Trademarks don't apply because you're not using them to identify your game in the marketplace (these are hidden deep inside the game, only seen after people purchase it). Copyright is an issue, because you're directly reproducing someone else's creative work, however, the incidental depiction of a product being used for it's intended purpose should be fair use (note that this is a grey area though)... It used to be commonplace in novels/books for real world products to be mentioned in stories in order to create a realistic setting, and there's legal precedent that such use is perfectly fine.

The other grey area is association. If you reproduce someone else's trademarks in your game, that might lead people to believe that this other brand actually endorses/supports your game. If your game gets bad press, this could cause damage to their brand (which could be worth a billion dollars)... Often websites have blanket disclaimers like: "All company, product and service names used in this website are for identification purposes only. Use of these names, logos, and brands does not imply endorsement" (note that such a disclaimer doesn't automatically put you in the right -- you could still lose a lawsuit).

However, if you watch American TV, you'll notice that even though this should be fine, brand names / labels are always blurred out, even when they appear in the background. The exception to this is product placement / advertising -- if you see a beer / soda label in a TV show / movie, it's because they've paid money to have it appear there as an advertisement...

The other reason that this is done is to reduce their risk of lawsuit. You can be doing something that's perfectly fine and legal, but still get sued anyway -- it's only at the end of the lawsuit that you find out whether you're right or wrong, and getting to the end might cost a lot of money. Worse; if you lose the lawsuit, you might be ordered to pay the legal costs of the other side, which could bankrupt you... So even when a TV show doesn't need to blur a label, they will do it anyway as part of a risk management strategy.

So the blurring serves two purposes -- it protects their advertising income stream by making product placement special, and reduces their risk of spurious legal attacks.

Personally, I like to get all righteous against the ever creeping scope of IP laws that stifle fair use, so I'd say go for it and damn the man! But sensibly, it's a good risk reduction strategy to avoid this altogether... :(