How would you know if you ate a bad prune?

If your monkey dies, the dates were bad, not sure if it works for prunes though.

The dates were poisoned. Not just mother nature trying to kill you, but another human.

You'd feel graped.

🙄

You know, buddy

Are there good prunes?

I'd wager they taste a little rancid and oxidised, but wouldn't do you any harm.

I bought a dozen prunes once. One didn't work.

Sadly the only way to answer that question is the hard way.