Recently the media hype about the tiny living things known as microbes has blown up, including controversy over antibiotic-resistance, and new research on bacteria that live in the human gut. The main punchline from stories like these: not all microbes are bad. In fact, they do essential things for our bodies, like help us digest food. They also make some popular food items, like beer, wine, bread, and chocolate, just to name a few. Microbe is a general term that refers to any organism that can only be seen using a microscope. Teams of scientists have taken to studying the microbes on our foods in hopes of finding new techniques to discover bacterial and fungal diversity. One great candidate for this research happens to be cheese!
Fig. 1 A variety of cheeses displaying the diversity of microbial rinds. The bacteria and fungi that make up these rinds are responsible for the colors and textures on the surface of cheese. (Source: Jorge Royan on Flickr https://www.flickr.com/photos/90129630@N00/ )
Think about all the varieties of cheese – from Camembert to Grueyère– which are teeming with billions of bacteria and fungi that give each cheese its unique flavor, color, and smell. Artisan cheeses, like many of the foods we eat, are not produced in a sterile environment, providing opportunities for microbes to colonize the surface. The microbes that cover the surface of cheese produce the rind, which is a type of biofilm, a mixture of sugars, bacteria, and fungi in a gelatin-like substance that enables the microbes to attach to moist surfaces. Microbes form biofilms in nature in order to protect themselves from toxins and antibiotics, to have easy access to food, to prevent drying out, and to easily communicate and exchange DNA. Some of the most pathogenic microbes are capable of producing these sticky substances, including the bacteria responsible for staph infections and stomach ulcers . In the case of cheese, the bacteria and fungi in biofilms are intentionally introduced from starter cultures applied by the cheese maker or from the environment where the cheese is made. These starter cultures are mixtures of good bacteria and fungi that prevent the bad microbes that cause disease from living on the surface of cheese. Biofilms such as cheese rinds are of interest to scientists because they provide a unique opportunity to study the diversity of microbes and the relationships and interactions between them.
Fig. 2 A microscpic view of the combination of bacteria and fungi within a biofilm. (Source: AJC on Flickr https://www.flickr.com/photos/ajc1/)
There are many types of bacteria and fungi that comprise the diversity of microbes on Earth. One of the major ways that microbiologists study these microbes is by isolating one type of microbe and growing them in the laboratory. Unfortunately many of these microbes are not easy to grow because they might require the presence of other microbes or an unknown mixture of food and vitamins, which limits scientists’ ability to study them. In addition to studying microbes in the lab, scientists also use genetics in order to determine which microbial species are present. This is essential for discovering the microbes that cannot be grown in the lab because it gives scientists a window into the microbial world which are otherwise too small to be seen. These two approaches are used on samples from environments other than cheese surfaces, like soils and water. Samples taken directly from the environment have more species than cheese, making them incredibly difficult to study.
Fig. 3 A collection of diverse cultured fungi found on the rinds of cheeses. (Source: Dr. David Midgley on Wikipedia https://en.wikipedia.org/wiki/Penicillium#/media/File:Ascomycetes.jpg)
Cheese has been made the same way for centuries and the cheese makers (and the microbes!) have a recipe that is proven to work. That means that the same microbes are likely to be found on the same types of cheeses, making them a predictable study system for scientists. In fact, after scientists sampled cheeses worldwide to determine the types of bacteria on the rinds, they found that most of the same species kept reappearing. They discovered that no matter where cheeses were produced across the world, there was a main mixture of microbes that kept showing up again and again. Cheeses from opposite corners of the globe were similar in the bacteria and fungi that they contained, sometimes even more similar than cheeses that were produced nearby . Scientists believe that this is due more to the manufacturing environment where cheeses are made rather than the geographic location of the cheese factory. Many artisan cheese makers apply salt washes or other treatments which influence the pH and moisture of the cheese. These are known to be controlling factors in the types of bacteria and fungi that can live in a certain area .
Through growing many of the major players in the cheese rind community, scientists were able to determine which bacteria and fungi like to grow together, and which species might depend on others in order to grow. This means that finally scientists are able to reconstruct a microbial community similar to what would be found in nature! This opens up novel avenues for exploring new microbes and figuring out what their capabilities . Scientists can then use the knowledge from simplified systems, such as cheese, and apply it to more complex environments like soil or the human digestive system. Cheese has always been a delicious and complex food, and now it is a scientific model for future research on environmental and health impacts. So the next time you dig in to that melty baked brie, thank a microbe!
Fig. 4 A slice of brie cheese with a white, bloomy rind, which is composed mainly of a fungus. (Source: Jennifer on Flickr http://chezlouloufrance.blogspot.com/2008/08/la-fte-du-fromage-brie-de-melun.html)
 Button, Julie E., and Dutton, R.J. “Cheese Microbes,” Current Biology 22(2012):R587-R589. http://www.sciencedirect.com/science/article/pii/S0960982212006598.
 Donlan, Rodney M. “Biofilms: Microbial Life on Surfaces,” Emerging Infectious Diseases 8 (2002): 881-890. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2732559.
 Benjamin E. Wolfe, Button, J.E., Santarelli, M., and Dutton, R.J. “Cheese Rind Communities Provide Tractable Systems for In Situ and In Vitro Studies of Microbial Diversity,” Cell 158(2014):422-433. http://www.cell.com/cell/fulltext/S0092-8674(14)00745-4.
More From Thats Life [Science]
- A Beautiful 9/11 Tribute, but a Fiasco for Migratory Birds
- Cats can have AIDS, too.
- Part 2: Does catching Pidgeys help you notice Pigeons? Interviews with Pokémon Go Researchers
- Biodiversity in my Backyard: Encounters with Pidgeys and Dratinis, Part 1
- Fins, Limbs, Rays, and Digits – A Beginner's Guide to Terrestrial Living
- Five things that really stink about the Brown Marmorated Stink Bug
- Tricks but no Treats - An Orchid’s Guide to Making a Fool of Your Pollinator
- Tracking the lost years - where do baby sea turtles grow?
- Posing as a Bird Mama: the adventures of a researcher-turned-bird-parent
- Hot moves and sexy sons · When Boys Become Men By Dancing
- The hungry caterpillar in real life
- Mantis Shrimp Vision - Seeing in Secret Code
- When It Comes to Bird Beaks - Size Matters
- Is your gut trying to kill your resolve? · Mind over microbe
- Recent talk of walls in the media has brought up a lot of emotions, but what do walls do in nature? · When a Wall is just a Wall
- Bees are more than buzzing insects around you · May the Bees Be With You: Maintaining the Sweet Balance in Life
- Neither a toad nor a worm · Nematodes: The super microscopic animal!
- Snap! Flash! Bang! Find out how ocean-dwelling pistol shrimp fire bubble ‘bullets’ to stun their unsuspecting prey. · How Pistol Shrimp Kill with Bubbles
- Who needs males after all?
- Ecology and Behavior of Woodchucks · Opposition Research on My Garden’s Greatest Nemesis
- Vision in Jumping Spiders · Watching Your Every Move
- Slimed and Consumed - The Blob is Real!
- The Evolution and Ecological Impacts of Cats · Lion in Sheep's Clothing
- What happens when frogs have to compete for acoustic space and a chance to be heard? · Struggling to be Heard - Competition in a Complex Soundscape
- Think Genghis Khan and Napoleon were the most successful invaders? Think again. · Invasive Species and Invasion: Part 1
- When, and how, terror birds invade
- 8 Reasons Plants Are Amazing
- Too Clean for Comfort · How our obsession with cleanliness might be hurting our health
- Stop, evaluate, and listen - serotonin surges when a female is present
- No Teeth, Long Tongue, No Problem - Adaptations for Ant-eating
- The Good, the Bad, and the Ugly - Predators, Parasitoids, and Parasites
- How our microbiome affects our health and vice versa · If you don't care for your microbiome, you might want to start
- Finding new ways to grow bacteria to progress science · Culturing the Least Cultured Members of Society
- Hit the Road Jack
- What Happened to Your Nose?
- Building better plants - Norman Borlaug and the Green Revolution
- Love Songs for Nobody - Birdsong in Winter
- We know we get infections from time to time. Why does this happen? · The Evolution of Virulence
- How cheese rinds may be a valuable tool for microbial discovery · The Unseen World – On Cheese?
- Find Me Where the Wild Things Are
- A commentary on how to make science more ‘clickable’ · You won’t believe this simple trick to tell if your coral is healthy or not
- Some species hide in plain sight, but scientists have ways to suss them out · Cryptic Species Hide in Plain Sight
- Minuscule Hitchhikers Pinch a Ride · Creature Feature - Pseudoscorpions
- World Fish Migration Day 2016!
- Walking With Giant Anteaters
- Why we should care about sea turtles · When A Sea Turtle Balanced Earth
- More ›