Mattheos Koffas (left), a biochemical engineer at Rensselaer Polytechnic Institute, and Andrew Jones, a graduate student in his lab, with a flask of microbe-produced antioxidants. Dan Charles/NPR hide caption

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Many artisan cheese producers never pasteurize their milk – it's raw. The milk's natural microbial community is still in there. This microbial festival gives cheese variety and intrigues scientists. iStockphoto hide caption

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Rugby and meat: a treat for the gut? A study suggests yes. Here Tony Woodcock (left) and Owen Franks of the All Blacks rugby team turn sausages on the barbecue in 2011 in Christchurch, New Zealand. Phil Walter/Getty Images hide caption

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Doctors used a rapid DNA test to identify a Wisconsin teen's unusual infection with Leptospira bacteria (yellow), which are common in the tropics. CDC/Rob Weyant hide caption

itoggle caption CDC/Rob Weyant

Even some euro bank notes may need a good scrubbing. Like dollar bills, these notes are made from cotton and they harbor an array of bacteria. Thomas Leuthard/The Preiser Project/Flickr hide caption

itoggle caption Thomas Leuthard/The Preiser Project/Flickr

Botulism bacteria, or Clostridium botulinum, grow in poorly preserved canned foods, especially meat and fish. The microbe's toxin could be lethal as a bioweapon. Dr. Phil Luton/Science Photo Library/Corbis hide caption

itoggle caption Dr. Phil Luton/Science Photo Library/Corbis

He's not just getting a cold. He's building his microbiome. iStockphoto.com hide caption

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Say hello to your microbiome, Rob Stein. Our intrepid correspondent decided to get his gut bacteria analyzed. Now he's wondering if he needs to eat more garlic and onions. Morgan Walker/NPR hide caption

itoggle caption Morgan Walker/NPR

We may not see them, but we need them. iStockphoto.com hide caption

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