Good question ! I have seen cutting boards, glued/clamped w/Elmers glue, last for decades. Ran across this : https://www.rockler.com/self-centeri...-thick-timbers Guy in instagram used to insert steel rod dowels, for mounting 8/4 Walnut floating shelfs : https://www.instagram.com/p/CEUvcFyF...id=bj6mkbyfan5 Combined with glue/clamp, would make a first class cutting board.
Use a water resistant glue and all will be well. I have made over a hundred cutting boards from 1 to 2 inches thick and up to 36" long using Titebond III, which is made for wet applications. No complaints yet.
I would use Titebond 3, If I was really worried I would join the pieces with a 1/2" x 1/2" tongue and groove. This would add a massive amount of glue surface, mechanical strength, and add a decorative detail at the ends.
That'd be my choice. Mechanical joint and maybe epoxy though TBIII would be cheaper. I'd also beg to differ that biscuits add NO strength. As much as mortise & tenon or domino? Clearly not. I remember a magazine test comparing different joining methods. Biscuits were the weakest but were like 500 lb. Mortise and tenon were 3000 lbs+. I built a microwave cabinet out of 3/4" hardwood ply hanging off a wall so there's some stress. The corners are mitered with biscuits every 6" or so. No joint failures of any kind. About the same time I built a couple towers 6'+ high for an entertainment center. Again 3/4" ply with butt joints no dados. They have been moved around some so racked and again, no joint issues. Just defending a joint that like Rodney Dangerfield gets no respect