MY QUORN NUGGETS are in the oven. I'm scared.

Now, I realize that food phobias are rampant in our culture. People are afraid of fat, caffeine, unwashed produce, raw-milk cheese. The media whip us into a frenzy by gleefully reporting deaths from salmonella and listeria; they describe in minute detail just what happens to your body as you die from ingesting E. coli. –Sadly, even though I try not to give in to the hysteria, I'm as credulous about food scares as your average Weekly World News fan.

That's why my Quorn nuggets are spooking me.

When I first heard about Quorn, however, a couple of years ago, I was ready to rush out and try it. Quorn, in case you're unfamiliar with state-of-the-art meat-free meats, is a line of vegetarian (but not vegan – egg whites are the binder) nuggets, patties, tenders, and dogs that are made not from soy or wheat but from cultured mycoprotein. According to the Quorn label, " 'Mycoprotein' comes from a small, unassuming member of the mushroom family, which we ferment like yogurt." Doesn't that sound nice? Like a small collective making vegetarian food the old-fashioned way.

OK, so far, so good. My family happens to enjoy vegetarian meat alternatives, and I had heard that Quorn was thought to be the best-tasting brand in Britain, where it has been on the market for nearly 20 years.

That was before my issue of Nutrition Action Healthletter arrived. This is a monthly newsletter put out by the Center for Science in the Public Interest. While some deride the CSPI as the ultimate buzz-killer, it's hard to argue that the country doesn't need nutrition watchdogs in an era of skyrocketing obesity.

I can smell the Quorn nuggets now as they're heating. It's a pleasant, savory aroma.

Nutrition Action paints an entirely different picture of Quorn. For one thing, when the label says Quorn is made "from a small, unassuming member of the mushroom family," what it really means is it's cultured from a fungus found in British soil. And "ferment like yogurt" means it's grown in big steel vats, not by some crunchy collective but by a sizable British food company that used be a subsidiary of a huge drug company.

But the worst news is that a small percentage of people who eat Quorn have reactions to it. And their symptoms are no walk in the park. The CSPI Web site has a page devoted to victims' stories, most of which involve bouts of violent vomiting that go on for hours, along with severe (and in some cases, incontinent) diarrhea. A couple of people went to the emergency room when they began seeing blood in their vomit.

Our (meat-eating) friend Ian just came in. My partner offers him a nugget without explanation, and Ian downs it before I can stop him. "It tastes just like McDonald's," he notes. He doesn't start vomiting right away, which encourages me. I take a bite. It's chewy, and pretty chickeny. The breading is crisp and dotted with black flecks of peppercorn. All in all, it tastes pretty OK for junk food.

I check myself for signs of nausea. Is sweat beginning to bead on my upper lip? Just what percentage of people do get sick? Gavin Grant, writing in the May-June issue of the excellent political magazine Clamor, comes out as a Quorn fan. He lived in Britain and enjoyed Quorn for many years, and when he returned to the United States was sorely disappointed with the meat analog offerings. He wondered why the CSPI was pushing so heavily against Quorn. Grant points out that the intolerance rate for Quorn is 1 in 146,000. "Compared to Quorn, the average person is 4,000 times more likely to have food sensitivity to fish or shellfish ... and 400 times more likely to experience an intolerance to that most popular of veggie staples, soy."

When I spoke to Michael Jacobson, Ph.D., CSPI executive director, I asked him about the 1-in-146,000 number that appeared in Clamor. That figure, according to Jacobson, doesn't come from a controlled study but from the Quorn company itself, based on the number of complaints the company received in one year divided by the number of people they estimate have eaten Quorn.

"That's bull," he said. "It's shameful, and it's shameful that the British government accepts those figures as the truth."

Instead, Jacobson maintains that the reaction rate is closer to 1 in 20.

"The company itself did a controlled clinical study years ago," he said. "Five percent of the people had nausea, vomiting, and diarrhea." The CSPI did a study of 1,000 people in Great Britain, asking them if they were sensitive to Quorn, soy, wheat, or milk. About 4.5 percent responded that Quorn gave them problems, versus 0.5 percent for soy. (If you got sick from Quorn, Jacobson would like to hear from you. Visit www.cspi.org to tell your story.)

Well, it turns out that neither Ian nor I is in the 5 percent of the population who hurl from Quorn. Jacobson wonders why we need to add a food with that high a rate of severe reactions to our food supply. I wonder what reaction rate might be right to allay my own anxieties. One percent? Two percent? I was fine with Quorn when I thought the rate was 1 in 146,000, but even though no one I know has gotten sick, with a five percent reaction rate, I wouldn't let my three-year-old have any of the nuggets. Still, I feed her soy, dairy, and peanuts, all known allergens, some that provoke reactions dwarfing Quorn's in severity.