Did you know that a can of tuna could contain, God forbid, chunks of shark or dolphin or something else that isn't kosher?
No? How about this: Did you know that a certain brand of salami, famous for answering to a higher authority, includes meat from cows whose lungs may not be totally smooth?
And that's not the worst of it: Oreos are made with lard.
You could learn a lot about keeping kosher on a tour of a supermarket with Rabbi Arye Weiner, West Coast director of the Union of Orthodox Jewish Congregations of America.
Pure nuts are kosher, for example, but you have to be careful with peanut butter. The emulsifiers that keep it from settling might have come from an unkosher animal source.
"Pure nuts is how I feel right now," someone in the crowd of more than 70 muttered.
"This is leaving me brain-dead," said another.
"Rabbi," came a plaintive plea. "I've got to live in the real world."
And why not? It took almost two hours for Weiner, 33, a tall, slim man in a pinstripe suit, purple tie and black fedora, to make his way from the liquor department on one side of the store to the fresh fish on the other.
Every aisle was fraught with surprises as the red-bearded rabbi, a graduate of the Lakewood (N.J.) Academy, one of the country's premier rabbinical seminaries, dispensed guidance to the perplexed.
"Concentrated orange juice?"
"All salt is kosher. We don't look for problems. We have enough problems as it is. So we don't go looking for non-kosher salt."
Any kind of hard liquor is fine, and so is beer, said Weiner. This raised a cheer. So did an announcement on the loudspeaker that the store now stocks fresh kosher chicken.
The crowd was made up largely of people in their 20s and 30s. Most of the men wore skullcaps; a few sported less traditional baseball caps. Among the women, a few covered their hair with scarves.
Some, who were born into observant homes, came to learn which supermarket products were in and which were out. Manufacturers can gain or lose their kosher status overnight.
Others, who came to the strict observance of traditional Judaism later in life, hoped to learn how to shop for the meals they liked before they accepted the restrictions of kashrut , the Jewish dietary laws.
"A lot of the older generation were content with matzo and gefilte fish and boiled flanken, and they considered that a satisfactory kosher meal," said Jodi Gross, 32, a librarian and housewife.
"But a lot of the younger people who become kosher later, who're used to fine foods, they aren't just content to eat matzo and gefilte fish."
"It makes your life a lot easier to be able to trust a product," said Sue Chenetz, 32, a limousine driver. "There are so many things we can cook with. The only thing that's missing is kosher gelatin. It just doesn't exist."
The evening at an Alpha Beta market in the Pico-Robertson district was sponsored by Weiner's group, which vouches for the status of 80% of about 17,000 kosher products in American supermarkets, and by Ashreinu, an Orthodox women's study group.
Weiner started the tour with a few warnings.
"I'll tell you bluntly," he said. "Keeping kosher is not a ticket to heaven."
Still, it couldn't hurt. The ancient rabbis claimed that a kosher diet can make the body a vessel for holiness.
Take the biblical injunction against cooking a goat in its mother's milk.
"Milk represents compassion and meat represents violence and death," Weiner said. "You can't combine these two forces in the universe. They don't go together. The whole ritual of kosher slaughter is to teach dignity with life and death."
Another warning was more prosaic: Beware the letter K on a product. Standing by itself, it is no guarantee that the contents are kosher.
Some foods--sugar, coffee, fresh fruit and vegetables, Grade-A butter--are kosher by nature. They don't need a kosher designation at all. Neither does medicine.
"Hypothetically, if the doctor told you to eat pork, you eat pork," the rabbi said.
"If you're taking it for a cold, fine. If you're taking it to get high, that's another question."
But foods that are not kosher by nature should carry the hekhsher (Hebrew for "seal") of an individual rabbi or inspection agency, observant Jews believe.
Many cheeses, for example, are made with rennet, an extract from the membrane from calves' stomachs. Since this amounts to mixing milk and meat, most cheese is out for Orthodox Jews, although rabbis from other, less stringent strains of Judaism have found that rennet is so far from being meat that it isn't a problem. Some rennet-free cheese is available with a hekhsher.
Other foods have natural or artificial flavorings that come from who knows where. Ambergris from the intestines of whales, for example. Or civet, from the sweat glands of a cat. All definitely not kosher.