Distinguish between organism and non-organism

Hello there and good morning (at least here in England).

I'm currently building a system that interacts with plants through capacitive sensing. Earlier
I used measuring the resistance of it, but it seems that capacitance measuring works more
reliable then resistance measurement.

I would now like to restrict this on living organisms. That means I want to find a way to distinguish
between if the person touches a plant (human, animal, food) or something nonliving like metal,
textile, etc.

Is there a way to do that? What attribute could help me to sense this difference?

Appreciate all the answers.
Thanks and best wishes,

Is there a way to do that?

The sensors on Star Trek can do that, but not in real life.

If you are willing to spend the time observing, something that reproduces is likely to be an organism.