Apparently there is a hot debate over whether Quinoa is kosher for passover:
Quinoa was unknown in the Middle East at the time of the Bible's account of the Jews' escape from Egypt, when their hurried flight left them no time to wait for their bread to rise. And since it was not part of their diet, it is not on the list of leavened grains forbidden to be eaten during Passover. For that reason, one of the nation's leading kashrut certification companies, Star-K of Baltimore, issued an opinion in 1997 that quinoa was kosher for Passover. At the time, the crop was grown mainly in Bolivia and was just beginning to gain popularity in the United States.
Increasing demand here for quinoa - which can be boiled or otherwise prepared in a variety of ricelike dishes - has driven up the price, persuading many farmers who grew wheat, corn or barley in Bolivia and Peru to plant quinoa as well, said Rabbi Menachem Genack, director of the kosher department of the New York-based Orthodox Union, the world's largest kashrut certification agency.
And there is the potential rub, Rabbi Genack explained. Some inspectors have found traces of wheat, and other grains susceptible to leavening in the cooking process, mixed in with quinoa shipped by some farmers, he said.
"They may be using the same equipment or bags to harvest a field of quinoa, and a field of something else," he said. "Things easily get mixed up."
The Orthodox Union has not certified quinoa kosher for Passover, leaving the decision to consumers and their rabbis. "We recommend that you inspect any product carefully before using it," the rabbi said.
It's an interesting illustration of the "loophole" problem that gets so much play every year as tax day nears. Sure, quinoa wasn't explicitly banned, but is that the real question? Or should we ask whether it would have been banned if the rabbis who interpreted the law had been aware of the existence of quinoa, and its future availability to Jews everywhere?