Wasabi has been deemed by experts as one of the hardest plants to grow commercially, and as a result it fetches a very high price, BBC reports.

The price is about $160 per kilogram, making it a food gold mine for one American company -- Pacific Coast Wasabi, owned by Brian Oates.

"It is much like gold -- we expect to pay a lot for gold. Well, we expect to pay a lot for wasabi," Oates told BBC.

So much of the wasabi that is often served with sushi tends to be watered down horseradish -- which is the same family as the wasabi.

Often what customers are served representing wasabi is actually a mix of mustard, European horseradish and food coloring, BBC reported.

So many people, even in Japan, have not tasted the real Wasabia japonica.

Estimates are as low as 5 percent for real servings of the wasabi from the rhizone, or root of the plant, in Japanese restaurants around the world.

The plant is found naturally in rocky river beds in Japan, but Oates has been pursuing commercial growth for 30 years.

But the history of wasabi use in Japanese culture is much older.

It was initially used as a way of preventing illness: the story goes that it was used on raw fish to prevent food poisoning, not because of its spicy taste, BBC reported.

And eating the wasabi involves simply grating it and eating it, compared to the powdered kind.

If the plant is fresh, the root is pushed on a grater made of a piece of sharkskin stapled to a wooden paddle, and using a circular, clockwise motion, one presses the rhizome down and a paste is formed, BBC reported.

One Vancouver restaurant, Zen Japanese, has been buying the authentic wasabi from Oates' company for years and selling it to customers.

"We send the grater out with the wasabi in it, and let them have the experience of grating fresh wasabi," Nobu Ochi, restaurant owner, told BBC. Once they taste it, like anything else that's good, you don't want to go back to the other stuff."