Well, a monkey testicle would be kinda gross to eat, and depending on the monkey species kind of morally repugnant too (some monkey species have near-human intelligence levels whereas others are just dumb animals).

But at least it's guaranteed to be "safe". The unknown meat could be anything - ground poison arrow frog, plague victim fillet, a chunk of my own cardiac muscle. So I'm going to skip out on the mystery meat.

I don't think it can be your own cardiac muscle, because you would KNOW where that came from.