Inhibition of Listeria monocytogenes by wooden cheese board microbiota

Obj 1. Analyze board microbiota; test Listeria growth on board surfaces. Obj 2. Analyze development of microbiota on select boards; test Listeria growth at different time points. Obj 3. Generate functional metagenomic library. Screen for anti-Listeria clones and identify compounds. Wooden boards are an essential tool for cheese ripening. The resident microflora on board surfaces directly contribute to the cheese microbiota and cheese sensory quality. Wooden boards are durable and can be re-used for many years. However, biofilms formed by the board microflora raise concerns about pathogen growth. Although the cheese microbiome has been studied, the composition and dynamics of cheese board microbiota are mostly unknown. In a trial study, we found diverse and complex bacterial communities on the surface of wooden cheese boards. Interestingly, the recoverable bacteria effectively inhibited Listeria monocytogenes (Listeria), a prominent dairy pathogen that is notoriously difficult to control. We propose to exploit the wooden board microbiota to develop protective cultures or food-grade compounds that inhibit Listeria on cheese ripening surfaces. Towards this goal, we will expand our microbiota survey to examine both bacterial and fungal species on wood surfaces for anti- Listeria activities. We will consider different wood types and ripening processes. Among those with the highest resistance to Listeria, we will examine the temporal dynamics of anti-Listeria microflora development during the ripening process. Finally, we will employ functional metagenomics, a high-throughput culture-independent approach, to identify diffusible compounds that inhibit Listeria. Our findings will directly inform safe cheese ripening designs and lead to the development of a protective application for ripening facilities.