You’re right to worry about this issue: a board that hasn’t been properly cleaned can help spread food-borne illness. After using a board or block, wipe it down with a clean tea towel moistened with warm soapy water. Next, rub the board with very fine steel wool to remove any residue sticking to the wood. Finally, rub a lemon slice over the entire surface.
How do I clean my butcher’s block and cutting boards so that they’re completely free of bacteria?