Despite my being obvious Emperor material in the Marcus Aurelius mold, if, and I stress if, I had been born into Roman slavery then the job of food taster slave would've been the best case scenario for me.
I'm not really cut out for heavy manual labor with my bad back. And I wouldn't last more than two minutes in the Arena as they'd surely hand me that ineffective net and trident combination. Sampling a plate of lark's tongue in aspic, however, would not be a problem. Neither would gulping down a mouthful of Falernum or two.
Sure, you'd run the risk of being poisoned, I guess. But drinking from an actual honest-to-God poisoned chalice? What a way to go. If you're going to die in servitude, the drama of clasping your throat with bulging eyes while dropping a golden goblet which clatters to the marble floor is certainly a spectacular exit for a nobody.
And even if you're lucky enough to never be poisoned, you can always milk the moment of food and drink tasting for all it's worth. A dramatic pause and worried expression after swallowing no doubt provided a great deal of amusement for the slave in question. It's fun to be the center of attention, after all, even if you'll never see the wild woods of Gaul again.