After dozens of boards of varying wood types and plastic types were subjected to the tests, the wood boards "won" hands down. In fact, the shocking part was that in ALL CASES, regardless of the type of wood used, the wooden boards REDUCED the presence of the various bacteria by 90-100%! It seems that the longer the bacteria were exposed to the wood, the more it "disappeared". On the other hand, the bacteria on the plastic boards, regardless of the temperature, actually INCREASED by the THOUSANDS of percentage points!