A week after I talked at length with Nobel Prize Winner Isaac Bashevis Singer about our respective vegetarian philosphies, I ordered a hot brisket sandwich on rye with mustard.

Singer's morality would never have permitted that.

I was raised as a strict vegetarian. Dad, now 72, believed, with Orthodox rigidity, that health is controlled by food: pure, organic, unpreserved fresh fruits, vegetables and grains only. My father is writing his first book, "Man Invented Disease."

Isaac Singer, on the other hand, is a vegetarian for ethical reasons: "I felt guilty eating meat and fish," he says. "I don't want to kill an animal. Why should I condemn murder if I am a murderer myself?"

Singer, 75, pours skim milk into oatmeal at breakfast at a restaurant near his oceanside apartment. He is recognized by a couple from New York whom he doesn't know. He chats with them congenially in his native Yiddish.

"When I was a young man in Poland, the men would wear fur coats to stay warm," he tells me later. "I always refused this. It reminded me every moment that the coat was taken from some animal."

Even though that sensitivity lurked in the background -- like the mystical goblins and demons in Singer's touching and adventurous stores -- it wasn't until 18 years ago that he refused the tasty flanken and chopped liver he once enjoyed.

He has never regretted his decision to become a vegetarian, he says. "The only thing is, I wish I had done this 30, 40 years before."

The Bible, which Singer, the son and grandson and rabbis, read before teaching a recent writing seminar at the University of Miami says, "And God said, 'Behold I have given you every herb-bearing seed, which is upon the face of all the earth, and every tree, in which is the fruit of a tree yielding seed: to you it shall be for meat." (Genesis I/29).

"Actually, the Bible looks askance on meat eating," said Singer, who studied for years in a rabbinical seminary in Poland. "Meat is always in the Bible a symbol of luxury and sinful egoism."

Singer believes that humanity will envolve to eating only fruits, vegetables and grains.

At home, with Alma, his wife of 40 years, Singer notes on simply prepared fresh fruits and vegetarian soups (lentil is his "most beloved soup"), honey cake and tea.

"Cooking for Isaac is easy," says Alma, who often prepares a small piece of meat for herself.

Invariably, early in the morning, Singer can be found a few blocks from his Miami Beach apartment eating oatmeal or poached eggs with grits in a drug store where he is celebrity. "I like grits because they taste good with skim milk," he says with a so-why-not smile. He also likes rye toast and matzoh.

Lunch is usually fresh fruit or "practically nothing . . . almost . . . mashed potatoes."

But then there are times, he teases, when he devours "half a goose and two living snakes."

He sipps coffee. "Meat eating in a way an affirmation of murder. If there should ever be peace in this world it will only exist among people who don't shed blood, neither of men or of animals. I don't know a single case of a vegetarian committing murder or any other crime of violence,'" he says. "A sincere vegetarian is a decent person."

Professor David Neal Miller, who teaches Yiddish language and literature at Queen's College of the City University of New York and the State University of New York at Albany says it's not surprising to find evidence of Singer's own food preference among his colorful characters:

"When Shlemiel went to Warsaw," he took "a few slices of bread, an onion, and a clove of garlic, put them in a kerchief, tied it into a bundle . . .," Singer wrote.

Lyzer, the miser, ate borscht while sitting on a box ("he used his chairs only by holidays so that the upholstery would not wear out"); Menaseh sat down in a berry patch deep in the forest, "picked out one berry after another and popped them into his mouth."

"Singer's characters are often his alter ego," adds Miller, who is writing a book about Singer.

Singer is quick to point out that, although he does eat some animal products, "You don't have to kill the cow to get the milk; nor do you have kill the chicken to get an egg."

Does he demand spring water like health conscious actress Gloria Swanson or will he drink from a public drinking fountain?

"Only if there is no bacteria there," he jokes. "I look first with my microscope and if I see one bacteria . . . because if there is a living creature, I don't want to destroy It. Neither do I want to destroy myself.

"Many people try to suggest that I became a vegetarian because I worry too much about my health, or try to stay young forever. This is far from the truth. Of course, I feel well for a man of my age. You may even say 'young' if you prefer to be nice to me.

"But my health and my vigor were not my purpose for becoming a vegetarian. It was completely an ehtical basis.

"I think vegetarianism must come to a person from his own meditation. It should never be forced. Even my own wife eats meat, and I don't make any propaganda," he says.

"The question you should really ask people," he advises "is why aren't you a vegetarian?"

I am a vegetarian, Isaac, but once in seven years a little brisket? It brings back memories, and I know you don't object to that.