## 4 Discussion
An analysis of wooden boards used to produce traditional Sicilian cheees showed they contained a complex microbiota on their surfaces [31; 32], and pathogens such as _L. monocytogenes_ were not detected. Although the use of wood has been called into question for putative hygienic reasons, there have not been foodborne outbreaks associated with its use [33]. Nor does wood appear to be effective at transferring pathogens to cheese. Fresh blocks of wood inoculated with _L. monocytogenes_ poorly transferred the organism to cheese [34], and _L. monocytogenes_ can be eliminated from wood when subjected to heat and chemical sanitization [8; 35]. We acknowledge that our study did not directly examine the inhibitory activity of the microbiota on the intact boards. Nor does it provide insights into the inhibitory mechanisms that these communities and isolates employ to limit the growth of _L. monocytogenes_ 2203. Future studies should investigate these mechanisms. We also chose to use a single cheese-associated outbreak isolate of _L. monocytogenes_ for this initial study. Subsequent studies should examine the generalizability of our findings to other relevant isolates of _L. monocytogenes_. Despite the limitations of our study, these data provide evidence that the complex microbial communities present on the surface of wooden boards used for cheese ripening might be inhibitory for _L. monocytogenes_, while also contributing to the desired sensory character of aged cheese. Although these results are intriguing, it is important to note they do not negate the potential risk from undesirable microbes that might be present on a poorly maintained wooden surface. The authors made the following contributions to this study: conceptualization, K.W., S.R. and C.C. ; methodology, K.W., A.S., S.R. and C.C. ; software, K.W. and A.S.; validation, K.W., A.S. and C.C. ; formal analysis, K.W. and C.C. ; investigation, K.W. and A.S.; resources, C.C., S.R. and G.S. ; data curation, K.W. and A.S.; writing--original draft preparation, K.W. ; writing--review and editing, all authors; visualization, K.W. ; supervision, C.C. and G.S. ; project administration, C.C. ; funding acquisition, C.C. All authors have read and agreed to the published version of the manuscript. This work was supported by a USDA National Institute of Food and Agriculture (Washington, DC, USA) Hatch grant WIS02007 to [PERSON] and by the University of Wisconsin-Madison Food Research Institute and the Walter and Martha Renk Endowed Laboratory for Food Safety (University of Wisconsin-Madison) to [PERSON]. Not applicable. Sources for this study are available in the NCBI's Sequence Read Archive under BioProject accession PRJNA884361. The authors declare no conflict of interest. * [PERSON]; [PERSON]; [PERSON] _Listeria monocytogenes_ in cheese and the dairy environment remains a food safety challenge: The role of stress responses. _Food Res. Int._**2015**, _67_, 75-90. [CrossRef]
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* [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] [PERSON] Characterizing the microbiota of wooden boards used for cheese ripening.