There's a risk for wooden ones that are glued, specifically bamboo, or finished with something toxic. You should probably stick to ones made from a single piece of hardwood and are unfinished.
There's also a risk that any cracks will fill with bacteria.
TLDR; unfinished wood that is rinsed and dried on all sides will naturally trap and kill bacteria as it dries. Any finish interferes with this process.
There's also a risk that any cracks will fill with bacteria.