Diving into the gene pool.

In Wisconsin, angry citizens dumped it into the streets. In San Francisco, chefs vowed never to let it cross their cutting boards. In Vermont, legislators enacted mandatory labels so that consumers could avoid it.

Welcome to the world of genetically engineered food.

It's one thing to manipulate genes to create miracle drugs like clot-busters, which can save the lives of heart attack victims. But mess with our food?

When you put genetic material from one plant or animal into another, you conjure up images of potatoes that glow in the dark so they can be harvested at night, pigs that moo...and worse.

Is genetic engineering a way to produce more-nutritious food with less damage to the environment? Or is it a disaster waiting to happen? Are we talking Sleeping Beauty...or Frankenstein?

CHEESE IT

Odds are you're already using genetically engineered products.

"There are at least 22 currently in use," points out Alan Goldhammer, director of technical affairs at the Biotechnology Industry Organization, the industry's trade group. Most are medicines--things like insulin to treat diabetes or interferon to treat cancer.

But some are foods. For example, some two-thirds of the cheese manufactured in the U.S. is now made with a genetically engineered enzyme called chymosin. It's an exact copy of rennin, the animal enzyme traditionally used to coagulate milk.

"Instead of scraping the stomach linings of slaughtered calves for the enzyme," says Goldhammer, manufacturers can now buy copies produced by genetically engineered bacteria."

Then there's the slow-to-turn-mushy Flavr Savr tomato and rBST, a growth hormone produced by genetically engineered bacteria that stimulates cows to produce more milk.

In the pipeline are potatoes that absorb less fat when fried, squash that's resistant to a damaging virus, and herbicide-resistant beans. Are they safe? Each will have to be judged on its own.

BEAUTY OR THE rBST?

For the first well-publicized food produced with genetic engineering, rBST milk could hardly have been a worse choice. All rBST seems to do is make more milk, something we don't need. The FDA set off a firestorm last November when it gave chemical giant Monsanto the go-ahead to market rBST.

Here's what you need to know about it.

* What is rBST? It's a laboratory version of the natural hormone that cows produce to regulate their milk production. The natural hormone is called BST (bovine somatotropin) or BGH (bovine growth hormone). The almost identical version made by genetically engineered bacteria is called rBST or rBGH ("r" stands for "recombinant," which means that the cow's BST-making gene was inserted into the bacteria's genetic material--its DNA). rBST injections can boost the milk production of cows (no, they're not mutant) by 10 to 20 percent.

* Does rBST milk contain harmful hormones? No. All cow's milk contains very small amounts of bovine growth hormone, whether natural or both natural and genetically engineered. rBST has no effect on humans, and it's destroyed by pasteurization.

Milk from rBST-treated cows may also contain slightly greater amounts of insulinlike growth factor I, which is active in humans. But it's destroyed in your gut during digestion.

* Does rBST milk contain "pus"? No. All milk contains white blood cells and other material from the immune system of the animal giving the milk. Critics of rBST call that material "pus" because they know that the word repulses people. "There is absolutely no health risk involved," says dairy expert Allan Bringe of the University of Wisconsin.

* Does rBST increase mastitis infections? Yes. The more milk a cow produces, the greater its chances of developing an infection of the mammary glands. Monsanto claims that rBST causes one extra case every ten years in the average dairy cow. Consumers Union, publisher of Consumer Reports magazine, says that the infection rate could be higher, and that using rBST is cruel to dairy cows.

Who's right? We may know in 1995, when Monsanto data on mastitis in cows using rBST should be available.

* Could rBST cause bacteria to become resistant to antibiotics? In theory. Disease-causing bacteria can become resistant to the antibiotics that farmers use to treat mastitis. The bacteria can contaminate the farmworkers, as well as the hamburgers that the dairy cow eventually becomes.

If those bacteria infect you, the antibiotics you take may not work.

"If rBST increased the use of antibiotics, that would be a problem," says Stuart Levy of Tufts University, who has been warning about antibiotic resistance for years. "But even then, I don't know if it would make me say that rBST isn't a good idea, because there are ways other than with antibiotics to treat mastitis."

HOT TOMATO

Few dispute that Calgene's new Flavr Savr "MacGregor's" tomatoes are safe.

Inserted into the Flavr Savr is an "antisense" gene, which neutralizes the gene that makes tomatoes soft. That means the Flavr Savr can ripen longer on the vine and can be shipped long distances before it becomes mushy. Calgene is betting that consumers will fork over $2 a pound for ripe tomatoes year round.

The only safety question concerns the "marker" gene that Calgene uses to identify successfully engineered tomato cells.

The company pairs the tomato's slow-ripening gene with a gene that makes the plant resistant to the antibiotic kanamycin. Then it exposes all of its tomato seeds to kanamycin. Those that aren't killed by the antibiotic contain the slow-ripening gene...and the kanamycin-resistant one.

Could the kanamycin-resistant gene be transferred from the tomato to bacteria in the large intestines of the people who eat it? "Everybody was satisfied that Calgene's tomato wasn't going to hurt anyone," says New York University's Marion Nestle, who served on the advisory panel that endorsed the FDA's approval of the Flavr Savr.

SHIRLEY...OR JOHN?

If milk from rBST-treated cows and the Flavr Savr tomato are safe, why all the fuss about genetic engineering? Some of it has nothing to do with safety.

The Flavr Savr "is aimed at capturing the organic tomato market," explains Ronnie Cummins, national director of the Pure Food Campaign, the group founded by Jeremy Rifkin that is leading the charge against biotechnology.

Cummins maintains that Pure Food doesn't oppose genetic engineering per se (although it has opposed just about every product that biotech has come up with).

"Our hidden agenda on this issue, just like on rBST," says Cummins, "is [to encourage] organic, or less chemically intensive agriculture and ranching."

Pure Food and others also oppose rBST because it may put small dairies out of business. Or they say that it's unethical to go beyond what traditional breeding can achieve. Some mistrust scientists' assurances that biotech is safe, or worry that new foods won't be reviewed as carefully as the Flavr Savr (products like rBST must go through more-rigorous approval as animal drugs).

The Flavr Savr is "like Shirley Temple," says Joan Gussow of Columbia University's Teachers College, a consumer advocate on the advisory panel that gave its blessing to the tomato. "What I'm worried about is a John Wayne waiting further down the line."

According to FDA guidelines, a company can market bioengineered plant foods without approval or the need for special labeling. But there are exceptions: if the nutritional value or level of toxins has been significantly changed, or if it has been given a substance that is known to cause an allergic reaction.

Still, it's up to each company to decide if a problem exists...a bit like leaving the fox in charge of the chicken coop. But at least for the next few years, "if any company hasn't consulted with the FDA and tries to blindly go ahead, they're going to be in for a lot of grief," says the industry's Alan Goldhammer.

In response to protests, the FDA now says that it will require companies to describe the safety tests they've done before they can market engineered foods.

This pre-market notification "could go some distance to alleviating some of my concerns," says Rebecca Goldburg, a biotechnology critic at the Environmental Defense Fund (EDF).

Goldburg believes that, of all the safety questions, "the allergy issue is the dominant one." Someone who is allergic to, say, shellfish, could suddenly become allergic to a new variety of broccoli that has been given a shellfish gene.

Will the FDA be able to tell whether the broccoli or other new foods are safe?

"If a company transferred a gene from a food known to be commonly allergenic, like shellfish, we would require labeling, unless the company can prove that the new food doesn't have the allergen," says James Maryanski, the FDA's Strategic Manager for Biotechnology.

But, counters Goldburg, "unless we take a protein from a food that's commonly allergenic, we cannot predict whether something will cause an allergy."

LABELING GENES

What irks consumers most is that the FDA is not going to require genetically engineered foods to be labeled.

"It's arrogant for the FDA and the industry to say 'we know what's best for you and we don't think you need to know this,'" says NYU's Marion Nestle.

"The FDA's labeling law is not a consumer's right to know law," counters the FDA's Maryanski, who adds that the FDA doesn't have the legal authority to require labeling based on how a food is produced.

Then there are the practical matters. For rBST, there's no way to test whether a batch of milk is or is not from rBST-treated cows. And it's one thing to label individual tomatoes. But it's not always possible to label tomato sauce, for example, which could contain tomatoes from dozens of farms.

While the labeling debate continues, the FDA should allow foods that aren't bioengineered to say so on their labels. They can now, but, in most cases, only if they add that the food is no safer than the genetically engineered version. That's cumbersome and unfair.

THE BOTTOM LINE

* The Flavr Savr tomato and rBST milk are safe.

* Companies should be required to show the FDA that the genetically engineered foods they plan to market are safe.

* The FDA should prohibit companies from transferring, from one food to another, any allergy-causing genes--not just common ones--that pose a health threat.

* Until consumers become more comfortable (or uncomfortable) with biotechnology, the FDA should require--to the greatest extent possible--that genetically engineered foods be labeled. It should also allow labels to say that foods are not bioengineered, with no qualifications.