I sell produce for a living, the sell by dates mean nothing there, sometimes the product will oxidize and go nasty a week before the magic date, and most of the time it's better than the bulk of the stuff we give to the soup kitchens.
Being a low-wage worker in the sticks, I can tell you I've been called various terms for female genitalia by the local community for what I won't eat (no rusty cans or animals that have been in the sun for two days please), I do have my standards. Syrup, nicotine, PG, and heat however are all things pathogens do not like.
If I found that stuff in the back of my drawer I'd give it the sniff test, if it passes then taste test, and then go from there. I wouldn't be worrying about the deadly space botulism from your juice.