My dog got into a backpack when he was a puppy and ate 3 chocolate bars. Dark chocolate, at that, which contains FAR more (as in, an entire order of magnitude) of the "toxic" compound than milk chocolate. He's just over 20 pounds now (absolutely massive for a papillon... but he's just big - very athletic and not at all fat), but he was just a small 12 pounds back then. And yet he still managed to survive, despite all the warnings that chocolate kills dogs. In fact, he didn't show any symptoms at all - had I not been living on my own, I would've been convinced that somebody else ate it and was simply framing my puppy. I've since learned that he absolutely LOVES chocolate (and most sweet stuff, really - he had a bit of fruit salad yesterday - but few things make beg as much as chocolate does.
And once in a while I'll give my little buddy a bit of beer. He loves beer, and hoppy ones are definitely among his favorites. The hilarious part is that he won't touch BMC. At all. He'll give any macrobrewed light lager a sniff, and then ignore it. My Pliny clone was probably the most eagerly consumed. Oddly, he also hates liver, and will eat nice Hungarian salami, but not cheap all-beef salami (I am the same). It's pretty funny, but my little guy actually seems to have a better, more discerning palate than most humans do!
Granted, when I intentionally give him "bad" stuff, I give him a very small amount, but he's had enormous amounts of many of these things in the past. He's had chocolate, grapes, raisins, onions, garlic, apricot, and (obviously) beer, and never shown symptoms. Don't get me wrong, I'm not trying to say chocolate (or hops) isn't bad for dogs - in fact, I'm quite familiar with the pharmacological effects of some of the chemicals in these foods - just that I think many of our furry friends are able to handle such things much better than we often give them credit for. Chocolate, for instance, isn't really "poisonous" to dogs any more than tea is poisonous to us. They just have a pretty strong response to the chemical theobromine, which is extremely similar to caffeine (and is even a metabolite of it), which makes it fairly easy for them to overdose on it, which isn't too different from a caffeine overdose. And like caffeine, if a dog consumes just a moderate amount of theobromine (keep in mind that "moderate" is an entirely relative term), there's no real harm done.
Now, I'm not advocating giving your dogs "bad" foods (and if you decide to do so, never just go ahead and give them several times more than they've had in the past - take it very slow)... but the warnings about these foods ate generally *way* overly-cautious, and with very good reason. But the point is really just that panicking or excessive worrying is usually totally unwarranted. Unless the dog consumed an *actual* poison, it's typically best to just keep an eye out for symptoms that would suggest a toxic dose of the food in question.