I sat down with Esther Miller, third year Ph.D. candidate at Tufts University, at her lab in Medford, Massachusetts. Amongst beakers of kombucha, Petri dishes of microbes from cheese rinds, and the scent of sauerkraut, she spoke about her current work with cabbages and a very unusual past research project.
Cook’s Illustrated: Tell me a little about yourself. What made you decide to get your Ph.D.?
Esther Miller: I took a little more of a circuitous route than most graduate students—I was a high school teacher for a few years. And then I worked in a really cool biotech company, which was making genetically modified mosquitoes, but I wanted to be more of a scientist than a regulator so I went back to university and found this lab. My first impression was, wow, “this is food AND science.”
CI: Why microbial ecology?
EM: I think microbial ecology (the study of the relationships between microorganisms, such as bacteria, yeasts, and fungi, their environments, and each other) is a cool topic because microbes are everywhere and how they interact can be used as a model for how animals interact and how ecosystems interact—but you can study it in the lab [as opposed to out in the field] and it’s a lot quicker and easier. I think the work we do in this lab is also relevant to the public; it’s relevant for consumers and for people who are doing fermentation, rather then just doing microbial ecology on a Petri dish with two species that you’re not likely to encounter [in the real world]—that seems too abstract.
CI: Tell us about your current research.
EM: I’m looking at how microbes come together in communities on the leaves of cabbages and then studying the function of those communities—how communities [of microbes] can produce a ferment. For example, it’s the bacteria on the leaf of a cabbage that create sauerkraut—they’re an important component, they have to be there. (Sauerkraut is simply cabbage mixed with salt that is allowed to ferment by lactic acid bacteria.)
CI: What are some experiments that you’re doing to understand these microbe communities?
EM: I grew cabbages at three different sites, brought them back to the lab, and then I fermented them and looked at how the pH changed during fermentation. As a ferment progresses, it gets more and more acidic, and that’s a function of the lactic acid bacteria that cause the ferment. So, the faster it ferments, or the lower the pH it reaches—it’s showing that the function of that microbe community is better.