Wood Cutting Board Finishes and Their Effect on Bacterial Growth

Abstract

Although wooden cutting boards have been used for centuries, debate remains on how best to coat/seal the boards for microbial protection. A growing body of the literature points to the hygroscopicity of wood—its ability to draw water and bacteria from its surface, deep into the wood, where the bacteria are trapped and die—as the wood attempts to even out its moisture content. There is little research as to how coatings affect this mechanism. In this study, four wood species were coated with either a hardening or nonhardening oil and then, were inoculated with either Listeria or Salmonella, then ‘stamped’ onto sterile agar plates at given time intervals to check microbial growth. The coated woods had significantly more recoverable bacteria on their surface than did the uncoated samples. There was no significant difference in performance between the oils. Remaining bacterial loads did vary significantly by wood species, with European beech having significantly less surface bacteria when inoculated with Salmonella, and the oak species having significantly less surface bacteria with Listeria. Multiple factors appeared to affect the ability of wood to move bacteria from its surface, including porosity of the wood, type of bacteria applied, and time. These results run counter to popular understanding of wood cutting board maintenance and will hopefully impact the way households and professional kitchens use and care for their food-contact wood in the future.