My Martha Stewart Hardwood Chopping Block (with four rubber
feet) splits in two after we left it in the rain. Here's how it begins. Over
time, the glues near the edges dry up creating gaps along the edges,
much like pine cones splitting under heat. The chopping block then
begins to show signs of splitting which eventually breaks in half under
a heavy storm.

I drill and insert several wooden dowel pins up and down the block. I
then join both halves together. I use no glue or preserving oil because I
couldn't find any food-grade glues or oils. I can see that it's a matter
of time before it breaks again, but elsewhere. What is a practical way
to keep a chopping block from splitting?

Thanks