I wondered about this too, considering the amount of waste involved in maintaining a culture.
Eventually, I settled on "No". It's not backed by science or anything, but it just doesn't feel right. I wouldn't eat raw culture, no way.
Sometimes the top of a culture can get moldy. It's part of the discard process to remove that / prevent it. At different times in a cultures life the microbial balance can shift.
And there are a ton of different strains of bacteria in there... I read a paper about how it's linked to the hands of the baker, and let me tell you... gross. It's a very complex ecosystem in there.
When using it to bake with, there's the safety provided by high heat. In a raw form, not so much.
That said, during jar changes I did a pre-rinse outside with a hose. Sometimes they needed to soak, so I filled them with water and left them. My neighbors chickens free-range and they helped themselves to refreshing beverages from said jars on multiple occasions. All of their chickens were fine. I told the neighbors and they didn't think it was anything to worry about.
I'm still not feeding it to mine!
