Finishes And Why You Don’t Want One

Given that the self cleaning capability of wood is dependent on the movement of water between the interior and the exterior, what is something that would inhibit that water movement? Finishes. Anything that blocks the movement of moisture between the surface of the cutting board and the interior will also block the beneficial movement of bacteria, leaving the bacteria on the surface of the board where it can cause cross contamination. Conditioning oils, waxes, balms, conditioning butters, food grade mineral oil (which is a petroleum product by the way), plant based oils (like coconut oil, linseed oil, tung oil, and walnut oil), as well at more aggressive finishes like polyurethane, and lacquer all inhibit the movement of water between the surface of the board and the interior. This means that the wood will become less efficient in moving bacteria, and will lose its self cleaning ability. Here is a LINK to a study that explains this process in more detail.

But won't my board dry out? Well, yes. Wood is supposed to be dry. Wood relies on the difference between the dry interior and water on the exterior to naturally kill bacteria.