I would only use wenge if you make sure the pieces ares 100% Quatersawn, so when a clear is put on it the wood it looks like ebony. Make sure there is Zero Cathedral Arches. I say this because of the way the pores are on wenge cathedral arched flat sawn lumber, it tends to blow out even long after sanding and sealing. The right pieces of Wenge, the super tight grain Quartersawn, the stuff I can hardly tell if it's wenge or ebony, isi what I look for when choosing Wenge. This is exactly why I use Wenge, I call certain pieces poor mans Ebony. A lot of the Quartersawn and especially the flat sawn arch grain wenge has a weird grain that is deep, stay away from it, especially if there is a whiteish or greyish color to it. It's these pieces that may come off in some form in a cutting board. I can take pictures. If you choose right and seal it right I can't see the right pieces of wenge ever effecting anyone, but the wrong pieces could. I use Wenge often, maybe every other day and it's one of the few woods I 100% have to go hand choose myself.
I use hundreds of woods and am allergic to zero, but when I get one little splinter of Wenge I can feel it, I am certain it's poison. And breathing Wenge makes me feel weird. Of course I am getting way more exposure than anyone using it as a cutting board would in 10 lifetimes. I believe a splinter of Wenge could probably put certain people into shock. I am sure you can google and if the information says anything other than that Ill be very surprised. I am betting Wenge dust causes dermatitis and splinters on the verge of making someone septic. I know this from using the wood myself, I hate the splinters and had one yesterday and my wife can't go near it unless it's sealed.
I see plenty of wenge on cutting boards, but be careful if you are selling or giving them away. Just choose pieces you are certain can't shed pieces later and seal it for food exposure.