Cheese Course

Benjamin Wolfe uses tasty fermented foods to study how microbes work
foodstuffs and lab sample tray
Blue cheese, brie, salami and kimchi are some of the raw materials that Benjamin Wolfe uses in his research on the interaction of different microbes in food systems. Photo: Kelvin Ma
March 4, 2015

Share

Glance into the cheese case the next time you’re at the market. See that velvety white rind on that buttery wedge of brie? The mottled rind on that tangy wheel of Gruyere? They’re actually little worlds unto themselves, hosts to a thriving ecosystem of microscopic creatures.

These tiny organisms—known as microbes—that live on cheese rinds may someday help us unravel the secrets of the human body or figure out how to tamp down disease-causing germs, says Tufts microbiologist Benjamin Wolfe. In his lab, Wolfe uses cheese and other fermented foods to analyze microbial activity, a step toward attacking these big-picture issues. But his work can also yield more immediate, practical results: helping government regulators devise food-safety regulations or cheesemakers figure out why a batch of blue has gone astray.

Food is a great educational tool, says Wolfe, an assistant professor of biology in the School of Arts and Sciences who came to Tufts last fall. “When you’re studying a pathogen or something scary, it’s hard to explain without making people uncomfortable. But put a wheel of Camembert in front of them, have them connect with the food, and they can connect with microbes.”

Wolfe takes his mission of microbial literacy beyond the classroom and the lab. He advises producers of handcrafted, fermented foods like salami and cheese—“we’re sort of the cheese whisperers,” he jokes. With his chef husband, Scott Jones, he coauthors the “Chefology” feature for Boston magazine; he also writes for the eclectic food publication Lucky Peach

“If the world had a slightly better understanding of the microbial world, we would be able to make better decisions for ourselves,” he declares.

Microbes Left and Right

“If the world had a slightly better understanding of the microbial world, we would be able to make better decisions for ourselves,” says Benjamin Wolfe. Photo: Kelvin MaMicrobes, the oldest form of life on earth, are everywhere. Bacteria, viruses, algae and fungi are examples of different types of microbes. Without microbes, neither humans, animals nor the planet would be able to function, because they are a vital part of all life processes. Some of the toughest problems confronting scientists and policymakers around the globe—the spread of devastating viruses like Ebola, or the rise of antibiotic-resistant strains of bacteria—are, at their very heart, about microbes.

Wolfe’s work addresses some of the basic questions about how microbes function and interact. The problem is finding a good venue for observing microbial communities. While microbiologists can inventory the population of microbes in a particular space—for example, in the human gut or in soil—they have so far been hampered in their attempts to recreate or dissect the complex web of microbial activity found in those natural environments. And while researchers have been able to isolate and study some individual microbes, such as the troublesome bacterium E. coli, simplified laboratory conditions do not mimic nature.

But in the middle—between a single bacterium in a flask and the trillions of microbes in the human intestine—lie the manmade microbial environments that exist in fermented foods like cheese, beer, salami or kimchi.

“There can be five, 10, even up to 100 different bacterial and fungal species living in fermented foods,” Wolfe says. “We know what they’re living in, because we created the environment. We know what they’re eating. The complexity is very reduced. Now we can say, Why do we see the patterns of diversity that we do? How are these species interacting with each other? Once we figure that out in a fairly simple system, that can be translated to a larger community.”

The Rind in Mind

These systems are not only useful for learning about the essential functions of microbes and how they interact with their environment, Wolfe says, but also for educating students and the public. “How do you teach about something people are generally afraid of?” he asks. While the vast majority of microbes are either benign or beneficial to humans, those that pose a threat—pathogens—are the ones non-scientists associate most closely with the word “microbe,” he says.

“Obviously, we’ve made huge advances in society in large part because we’ve been able to figure out how to fight against the bad microbes,” Wolfe says. “But we’ve also made huge advances because of improvements in food preservation and the quality of food through good microbes. The good guys don’t get enough attention.”

Last year, Wolfe and colleagues from the Dutton lab at Harvard, where he did postdoctoral research, published a paper in the journal Cell that documented the microbial diversity they found on rinds from 137 types of cheese.

Among the findings: the style of rind—rather than the geographical origin of the cheese—correlated with the species of microbes that appeared on various cheeses. (There are three main styles of cheese rinds: natural rinds, which are largely untouched during aging; bloomy rinds, which are inoculated with fungi; and washed rinds, which are bathed with a salt solution.)

An example of how such data can be useful, Wolfe says, is in the U.S. Food and Drug Administration’s ongoing efforts to devise food-safety regulations for cheese production, particularly for handcrafted, small-batch artisanal cheeses.

“Before this, no one had published about what was growing on the rinds of artisanal cheese in the U.S., which is surprising, considering how many people buy a Camembert at the farmer’s market and put it in their mouth,” says Wolfe.

“Cheese is a very traditional food, and has to be made in a certain way, but a lot of those traditions are challenging in a modern food-safety context,” he notes. “By doing some of the science, we can help both the cheesemakers and the regulators.”

He points to issues such as how long raw-milk cheeses should be required to age before they can be sold, or whether cheese should be allowed to age on wooden boards, both of which have been points of contention between the FDA and cheesemakers.

“Along the way, we’re also learning a lot of useful things that cheesemakers are super excited about,” such as the origins of particular molds, Wolfe says. His team does its fieldwork at the cheese caves at the Cellars at Jasper Hill in Greensboro, Vermont.

Other cheesemakers from around the country send samples to his lab for analysis—“if the rinds aren’t growing the right way, or there’s something strange that’s making it smell interesting,” he says. “This is basic science lining up with a very applied problem.”

Helene Ragovin can be reached at helene.ragovin@tufts.edu.