Wasabi

About 99% of all wasabi sold in the US is fake, reports The Washington Post. The vast majority of wasabi consumed in America is simply a mix of horseradish, hot mustard, and green dye.

True wasabi is difficult to grow and extraordinarily expensive, costing $160 a kilogram at wholesale prices. If you're eating real wasabi, you're consuming the stem of a plant, grated and pulverized into a spicy paste. It reportedly has a more complex taste, but needs to be eaten immediately — within 15 minutes, the freshly grated wasabi begins to lose its signature flavor.