Problem with end grain brds is they also suck up and retain fluids that harbors bacteria.
Best cutting brd I have ever Had was a 24 inch end grain japanese round doug fir brd, 4 in. thick
always had mold on it.
studies show that end grain and in general wood boards collect the lease amount of bacteria.
If you oil your board on a reg basis then nothing gets in. Wiping with vinegar once a week also prevents bacteria accumulation.