|Maple is traditionally used for butcher blocks even though it is not the hardest wood. The belief is that there is something in maple that naturally inhibits bacterial growth. At the end of the day, the block is scrubbed hard with specially tempered hard wire brush. I suppose that besides cleaning the pores of the wood of fat and blood, the newly exposed wood starts the cycle again.
But as for spoons, on one of the Woodwright Shoppe episodes Roy visited with a spoonmaker who made spoons from a variety of woods including poison ivy vine.
Generally speaking, you probably should NOT use poison ivy vine, nor any of the woods with a reputation for toxicity or alergic reactions.
So, woods to avoid would be black walnut, most of the tropical exotics especially cocobola and rosewoods, redwood, cedars, etc. Probably most softwoods, being resinous, would at least tend to add some undesireable flavors to the food.
Woods that have been commonly used for kitchen utensiils include orchard woods like apple or pearwood, and also olive, maple, cottonwood, beech, birch, bamboo, cherry. Sassafras is the wood of choice for peels (pizza oven shovel).
Probably it would be best to avoid porous woods like red oak, avoid Yew it will make you ill, teak will leach oils which will taint anything you use them on.