About three weeks ago the Los Angeles Times ran a story about shio koji, or rice inoculated with Aspergillus oryzae, a benign mold that’s been used for centuries in the production of miso, amazake, and sake—Japan’s sake brewers have dubbed the spores a “national fungus.”

About five years ago the matron of a 300-year-old koji manufacturer began experimenting with the stuff in a variety of recipes to boost the family’s flagging business. Her promotional efforts led to a national craze, with chefs and home cooks using it for everything from marinating meat to pickling vegetables to spiking soups, pastas, baked goods, and salad dressings. There’s even a manga character named after it. Hailed as “the new MSG,” it’s considered an umami booster, enhancing the flavors of whatever it’s used with. Pretty much anything salt can do, koji can do better, say its boosters.