another argument
Bacteria
It is often said that plastic is easier to clean than wood, but this is not necessarily the case. Foods that stain are much easier to clean off plastic, but if you're concerned about bacteria, plastic may not be the material you want to choose to use.
Shop: Farberware 3-Piece Poly Cutting Board Set Plastic cutting boards have a nonporous surface that provides no place for bacteria to dwell. However, bacteria can just as easily live on the surface and after using the board for a while, your knife will probably chew up the fine surface of the board providing plenty of hiding spaces for bacteria to survive even through vigorous washing. This is troublesome to deal with and it is wise to scrub the cutting board down immediately after using. What Shop: Farberware 12x18 in. Poly Cutting Board with MicroBan
about those plastic boards that have built in antibacterial chemicals? These only serve to inhibit bacterial grown that causes stains and odors - they do little to kill food-borne bacteria. If they did, you'd be ingesting poison agents every time you used your cutting board. Vigorous scrubbing with hot water and soap and an occassional cycle through the dishwasher is probably your best bet when it comes to plastic. (Be careful, some low quality boards may warp in a dishwasher.) Unfortunately, even a dishwasher's high temperatures may not be enough to kill all the bacteria. You're sure to kill quite a few of them, though. Pouring bleach (diluted in water) over the board is also a good way of purging the board of bacteria. Once you've got the board clean, keep it dry. A few hours of complete dryness will kill the remainder of the bacteria. Make sure you prop up a corner of the cutting board if you're leaving it on the countertop so moisture won't be sandwiched under the board.
Shop: Farberware 3-Piece Wood Cutting Board Set Wood cutting boards deal with bacteria in the opposite way that plastic boards do. Wood boards actually absorb the bacteria into the wood. After the surface of the wood has been cleaned and dried, the bacteria near the surface dies. It turns out the wood near the surface forms a hostile environment for bacteria to live in. There are lots of bacteria living in the cutting board, but about 1/8 in. below the surface. This is deep enough that a heavy handed chop into the wood is unlikely to release bacteria (unless the wood splits). If your cutting board fits in your microwave oven, heating up the board in the microwave for 30 sec. or so will completely cleanse the board of bacteria, inside and out. As with plastic boards, prop a corner up to keep moisture from collecting.