Who knew that yak, sheep testicles and elk could be kosher? More than 120 people who attended a Chicago “mesorah” dinner last weekend have now sampled these exotic foods, without violating any Jewish dietary laws.

The 15-course meal, which alternated innovative dishes with discussions and presentations on the laws of kashrut, was organized by Dr. Ari Greenspan and Rabbi Ari Zivotovsky, in conjunction with the Chicago Rabbinical Council.

The two Aris, both residents of Israel, met as 18-year-old yeshiva students learning the art of shechita, ritually slaughtering meat. While the Torah is explicitly clear about certain prohibitions — like the one on pork — other rules are more open to discussion. The Torah names 24 birds as not kosher, with the implication that the remaining ones are kosher, as long as one knows how to properly slaughter them. Since Greenspan and Rabbi Zivotovsky met, they have been “doing what we call halachic adventuring,” said Greenspan, “which is traveling the globe doing research in Jewish history and Jewish law.”

Whereas once every community had its own shochet (kosher butcher), today most meat eaten in kosher homes comes from large producers, which means that only the most common animals are available. Without more rare animals being eaten, the duo is worried that the mesorah — the transmission of the laws regarding the kashering process — will be lost.

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The dinner in Chicago was the fifth such evening that Greenspan and Rabbi Zivotovsky have organized, with previous events in Israel, New York and Los Angeles. When the CRC approached the duo to hold a dinner in Chicago, they were more than happy to share their knowledge.

“We served everything to teach something,” said Greenspan. “We don’t serve anything just because it’s something crazy.” But crazy it was, with a menu ranging from elk to partridge to a South American fish called tambaqui. A close relative of the shibuta fish, which is noted in the Talmud as tasting like pork, tambaqui was substituted for shibuta because of complications importing that fish to the United States.

The course causing the most consternation among diners was the sheep testicles. The restaurant listed them by their French name, animelles, and the crowd only found out after the dish had been served exactly what they were eating. After the announcement, “one guy got up and left the room,” said Greenspan.

One of the most surprising dishes was that containing both meat and milk — cooked together. The cow’s udder contains milk inside it at the time of slaughter, and “anything that has been slaughtered inside a kosher slaughtered animal is kosher,” said Greenspan, “and as a result it is considered to be meat. Halachically it is not milk.”

And while past versions of the mesorah dinner have served locusts for dessert, the supervisors in Chicago were unwilling to include them in the menu, because of doubts that both Ashkenazim and Sephardim are allowed to eat them. Instead the restaurant — Shallots Bistro in Skokie, Ill. — created a locust-shaped chocolate, and the group heard a presentation on insects in Jewish law.

“All of these things together made it an amazing gastronomic experience,” said Greenspan, “and people walked away saying it was one of the most interesting educational experiences of their life.”

For more information visit www.halachicadventures.com.