The wood in contact with food is regulated so that should not be treated with chemicals for preservation or phytosanitary treatment. In some cases in wood packaging manufacture it only suffers a final drying process (reduction of moisture content below 20%).
Any way, there is a clear difference between the level of content of certain natural compounds from the timber or its traces, and the level of those that may result from treatment or contamination.
On the other hand, in wood packaging is not common the use of special coatings. This is more common in household and kitchen utensils of wood, sometimes using natural coatings allowed to improve their properties (solvents, waxes and oils)