Human bodies teem with trillions of microbes, a complex assemblage of bacteria, eukaryotes, and viruses essential for human health and wellbeing. This microbiome is the result of the foods we eat and the places where we live, but humans are not passive in our environments: we domesticate species, change habitats, and process foods in ways that have distinctive and synergistic effects on microbial communities. By consuming probiotic bacteria, humans can modify the microbiome within our guts to reap substantial health benefits ranging from neurological function to immune response. The keys to understanding the interactions between fermentation and the gut microbiome lie in the processes and technologies by which foods are fermented – a cultural as well as biological question of microbial activity, diet, fermentation practices, and local culinary traditions. In this project, we combine research strategies from biology, genetics, and cultural anthropology to investigate how local knowledge and cultural practices associated with fermented food production directly impact microbial communities within ourselves. This project is funded by the Purdue University College of Liberal Arts Global Synergy Grant.