Brio you could have handled this in your original thread. They were already dead when you bought them. They're preserved in citric acid etc. They should be fine, assuming you didn't leave them out in the sun or something. If they smell rotten, the bottle should be tossed.
I would use it by the expiration date. But don't over feed or you'll be sorry. I freeze unused product if I have left overs a few weeks after exp date.