Supermarkets Present Kosher Challenge : Religion: Salt, coffee and fresh fruit are OK, but forget canned fish and, for heaven’s sake, stay away from the Oreo cookies. Those and other tips were offered by a rabbi on a recent food shopping tour.

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.

Oy.

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?”

“No problem.”

“Kosher salt?”

“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.

“Cough syrup?”

“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.

Even vegetarian baked beans could have been canned on the same line as pork and beans, you should excuse the expression. If the can carries a hekhsher, the assumption is that somebody was watching to make sure the equipment was pork-free.

Which doesn’t mean that it’s good for you necessarily.

“ Kishke (stuffed sausage) can kill you,” noted Paul Glasser, the former executive vice president of an Orthodox synagogue in Beverly Hills. He and partner Sheila Bailey are organizing a Jewish festival featuring kosher products at the Los Angeles Convention Center next month.

“People think kosher food is blessed. Kosher food isn’t blessed; it’s supervised,” Glasser said in an interview. “Somebody’s watching it, but not for calories or cholesterol.”

At the supermarket Tuesday night, Mariam Weisel, 26, a medical secretary, was surprised at some of the complexities of keeping kosher.

“I’m finding out that things I thought were kosher are not, and things that I thought weren’t kosher are OK.”

Meat always needs a hekhsher , since Jewish rules call for it to be slaughtered and inspected by trained experts.

Fish does not need expert slaughtering, and many varieties of fish are kosher by nature. But canned fish could have been prepared in the same plant as shrimp, which is forbidden.

“Rabbi, that can of fish over there has a hekhsher on it,” said a wise guy in a baseball cap. “Does that make it holy mackerel?”

All observant Jews rely on the same laws and rabbinical interpretations to keep kosher, but each household has to make its own decisions on what to buy.

“People have their own stringencies they impose on themselves,” Weiner said. He pointed out that supermarket milk, which is fine with him, would not be admitted into some homes.

Sorting out these questions can keep rabbis busy. Weiner, who operates a “kosher hot line” from 8 to 10 p.m. from his home in the Fairfax District, says he gets as many as 40 calls a night. (The number is 965-9125).

As for Hebrew National, the firm that claims to answer to a higher authority, its meat comes from cows that may have more lung-scarring than the Orthodox Union would like, but it is still kosher, Weiner said.

“All of our products are fully inspected. We don’t claim to be glatt kosher,” said Steven Bachenheimer, president of Bronx-based National Foods, which makes Hebrew National products.

Glatt, the Yiddish word for smooth, refers to meat from cows whose lungs have been found to be totally free of scars.

“With the standard kosher product, you’re permitted to have some level of scarring,” he said in a phone interview. “It’s not that the animal is sick. If it was sick the USDA would catch it. This is a kind of second level of inspection.”

Although observant Jews are the bedrock of the kosher food market, Bachenheimer said the demand is growing from the general population.

Glasser agreed. He quoted from a study that found 6 million people in the United States following diets that fall within the rules of kashrut.

Of these, only about 1.5 million are Jewish, Glasser said. The rest are vegetarians, Muslims or health food devotees.

“We estimate that half our business today is with people who are not Jewish,” Bachenheimer said.

“Kosher has come to signify quality to a lot of people. And I think there’s a trend toward the mainstreaming of Jewish foods. Like bagels. What’s going on is that people are gaining a taste for things that traditionally have been Jewish foods, much like they acquired a taste for pizza years ago.”