Look at this:
This dishwasher-safe cutting board is made in the USA of Richlite, an exceptionally durable wood-fiber composite that has been used in commercial kitchens for over 40 years.
- Made of Richlite, a lightweight yet durable wood-fiber composite that won’t dull knives, harbor bacteria or absorb unwanted flavors and odors.
- Has a convenient corner hole for hanging.
- This NSF-certified board meets the high-level safety standards for professional kitchens
I got one of these in a package deal with a Wusthoff carving knife and have run it through the dishwasher a few times - it seems just fine after going through. I was talking with a woman at a kitchen store and she said she puts hers in the dishwasher "all the time".
The best cutting boards are the end grain type that cost the most but do not dull your knife. For a good one of those you are gonna pay $100 and up.