This tray is not painted not has it been coated or varnished.

As it is a natural product, there might be some minor imperfections and areas harsh to the touch. You can use a soft sandpaper to even and smooth the surface.
You can paint of varnish the tray with a water based varnish or olive oil.
Some minor color imperfections might occur.

Ideally you can glue a non-slippery surface on the inside of the tray to assist the child in carrying items on the tray.