As a follow up to a recent TALK discussion of food safe finishes, I dug out two relevant references on cutting boards that I found years ago:
U of Wisc. Study showing wood cutting boards have a lot less bacteria than plastic cutting boards. Wood has chemicals that kill bacteria while the chemicals in plastic. https://www.treenshop.com/Treenshop/ArticlesPages/SafetyOfCuttingBoards_Article/CliverArticle.pdf
Recommendation from the FDA that only “closed grain” wood be used for cutting boards:
(A) Except as specified in ¶¶ (B), (C), and (D) of this section, wood and wood wicker may not be used as a FOOD-CONTACT SURFACE.
(B) Hard maple or an equivalently hard, close-grained wood may be used for:
(1) Cutting boards; cutting blocks; bakers’ tables; and UTENSILS such as rolling pins, doughnut dowels, salad bowls, and chopsticks; and
(2) Wooden paddles used in confectionery operations for pressure scraping kettles when manually preparing confections at a temperature of 110oC (230oF) or above.
From chapter 4-101.17 of https://www.fda.gov/media/110822/download
Apparently this is not “Law”, just advice from the FDA. As the document says: “The Food Code is a model for safeguarding public health and ensuring food is unadulterated and honestly presented when offered to the consumer. It represents FDA’s best advice for a uniform system of provisions that address the safety and protection of food offered at retail and in food service.”
All you can say is that the FDA recommends closed grain wood for cutting boards – but they could be wrong and closed grain is bad. They do not recommend open grain wood but they could be wrong and it is OK to use. Caveat Emptor.
I have a hand held microscope (because I am a nerd, and proud of it) and went around my woodpile and found:
Tight – no to almost no voids, ie “Closed Grain”: Maple, Cherry, Purple heart, Paduak, Birch, Aspen, Sapele, Blue stain beetle kill pine, Cypress, Birch, Sycamore, Cottonwood, White oak (but only because the voids are filled with some crystalline thing), Bois D’arc
Semi tight – some small voids spaced out: Walnut – can vary a little bit. It is definitely more open than maple but voids are much smaller and fewer than red oak/ash. Live oak (some variability, some was tight), Lace Bark Elm
Semi Open - mostly closed but some larger voids (2x the void size of semi tight): Wenge, Post Oak
Open Grain – wide open – you could drive a truck through the voids: Ash, Red Oak, Honey Locust
Mesquite, hickory and pecan range from semi tight to semi open. There are hundreds of Pecan/Hickory species.
The wood database has pictures of end grain for most species. Examples