Overview: Fermented foods are a staple of the Japanese diet, and they come in countless forms: soy sauce, miso, vinegar, pickles, natto and more. Because they keep well and are high in nutrients, they were historically favored as energy foods and even military provisions. Studies are now going on to use them to solve environmental and food-supply problems. Our expert guest is Makoto Kanauchi, a scientist who researches fermented foods. And in Plus One, taking on a seriously fermented food challenge.