I'd be concerned that the wax would merely form a water-repellent surface coating. That's fine for furniture. But it's the opposite of what you want with a cutting board---particularly an end-grain type.
Part of wood's anti-microbial property comes from the fact that the baddies are drawn down into the dry interior, where they cannot grow because the environment is wrong for them. If you clog the surface you negate that function. |