About 15 years ago when I was still in the food industry I remember a chocolatier telling me she didn't believe it was possible to be genuinely completely sure

About 15 years ago when I was still in the food industry I remember a chocolatier telling me she didn't believe it was possible to be genuinely completely sure there was no child or slave labor in your chocolate. You could get the number low, possibly zero, you could with a lot of effort get a snapshot of your supply chain at a point where the number was plausibly zero, but you couldn't guarantee it was actually at zero over any length of time. It's entirely possible the situation has improved since then, I have no particular knowledge either way.