I just read an article from Fine woodworking (Nov/Dec Issue 2024) by Seri Robinson, a professor of wood anatomy:
Here is a few quotes from the article: "As a professor of wood anatomy, I’ve done quite a bit of research into food-safe finishes. The results might surprise you. One thing everyone seems to have missed is that wood doesn’t have a bacteria problem. Unfinished wood is naturally antimicrobial. In fact, when rinsed and dried properly between uses, it is self-cleaning. Wood finishes only serve to undermine this amazing property of wood....
Popular wisdom says that microbes multiply in raw wood, growing and waiting until—Whammo!—the listeria army attacks your charcuterie party. That’s not how raw wood and bacteria interact, and there are decades of research to back this up, as well as centuries of safe contact between food and unfinished wood. Here’s what is actually happening.
Wood is constantly gaining and losing moisture from the air around it. In scientific circles we refer to this as wood’s hydroscopic property. Wood does the same when it comes in contact with any liquid, such as water from a sink or juice from an uncooked steak....So if bacteria is drawn into the wood with moisture, why won’t it come back out and wreak havoc? If you give your cutting board or spoon a rinse after use and let it dry on all sides, the drying action will continue to pull bacteria deep into the wood, where it will be trapped and die. Little to none will be left on the surface, at least not enough to transfer. This is what I mean when I say wood is antimicrobial."
*One note she mentions is: "If you absolutely want the look of an oil finish, go with just one coat, and avoid raw or unrefined natural oils such as olive oil, grape-seed oil, and raw linseed oil. These can take months to cure if they cure at all, and they can become rancid.... The worst option for food- or kid-related items is any finish that is formulated for outdoor use, as it is likely to contain dangerous chemicals."