The impact of environmental conditions and milk type on microbial communities of wooden vats and cheeses produced therein

Wooden vats are used in the production of some traditional cheeses as the biofilms on wooden vat surfaces are known to transfer large quantities of microbes to cheese. Variability in microbial communities on wooden vats could lead to inconsistent cheese production. In the present study, the influences of environmental conditions and milk type (raw or heat-treated) on the microbial composition of vat biofilms and cheeses made in the vats were studied using amplicon sequencing of bacterial 16S rRNA and fungal internal transcribed spacer genes. Results showed that the microbial composition of biofilms was influenced by environmental conditions but not the milk type used in cheese production. The microbial composition of cheeses can be further affected by bacterial contributions from milk and the selective forces of environmental conditions. Results of this study suggest that controlling environmental conditions could maintain a more consistent microbial composition of biofilms on wooden vats and resulting cheeses. The use of wooden vats coupled with heat-treated milk at one or more stages of cheese production might be a viable approach to produce cheese with high microbial diversities and reduce risks of undesirable microbes related to food safety and quality. •Biofilms on wood serve as a major source of microbes for cheeses made in wooden vats.•Microbial community structure of biofilms change with repeated cheese production.•The biofilm microbiota were affected by environmental conditions but not milk type.•The cheese microbiota were affected by bacteria in milk and environmental conditions.