When Andrew Borba shows up in the episode "Never Kill a Boy on the First Date" (S01E05) of Buffy the Vampire Slayer, he starts ranting about "pork and beans". Is that just random gibberish, or is it some kind of inside joke or easter egg? Did the writers ever say where the phrase came from?
While it's easy to disregard Borba's words as the random raves of some lunatic, I believe there is a more logical explanation here. I think he's just talking about canned pork & beans, with nothing easter-egg-y about it, and that the phrase was simply chosen because it fits his character and world view.
Let's examine who this guy is. We first see him on a city bus all dressed in military garbs, harrassing passengers and spouting semi-religious rants about Judgement Day. He's big, menacing, unkempt and basically seems like some transient or veteran that's gone mad, or a deluded militia man (we later find out he's a suspect in a double homicide). Then, after waking up in the funeral home, the now-sired Borba sees a group of teens before him and says this:
He is risen in me! Pork and beans. Pork and beans! I can smell you. You're the chaff, unblessed. I'll suck the blood from your hearts, he says I may!
Vampire Borba is simply equating the teens fleeing from him to food here. And it's specifically this kind of food because canned pork & beans is probably something he's familiar with, whether as a transient or from prison or the army, and he's equating them to something cheap since they're insignificant to him now in his new 'exalted' state.