Don't ever use treated wood where you plan to prepare food. The chemicals used to treat it are toxic.
Another thought. Call around to granite shops and ask if they have any sink or stove cutouts from cabinet jobs. they usually throw them on the scrap heap, and you can get them for nothing. They will usually cut them to size for a small fee. Makes a great prep area built into the table top.
Make sure you post pix when you're done.