These complaints have gone mostly unheard by the regulators who approved the product—until now. The Center for Food Safety, a consumer advocacy group based in Washington, DC, has filed a lawsuit against the FDA alleging that Quorn (plus a handful of other products) is evidence of a faulty food additive approval system here in the states. What is Quorn actually made of? Mold, to be exact. Its main ingredient is mycoprotein, made by fermenting the fungus Fusarium venenatum in a broth of glucose and minerals. Later, the fermented solids are mixed with binders (mostly egg whites and wheat protein) and whisked off to your grocery store. Whose idea was this, anyway? A now-defunct UK company called Imperial Chemical Industries. They discovered the fungus growing in the soil of Buckinghamshire in 1967. Back then, many researchers believed that population growth would soon outpace food production, and Quorn’s founders developed mycoprotein with that fear in mind. In a strange turn of events, it has ended up in the freezers of adventurous vegetarians everywhere, for whom weird shit like Tofurky just wasn’t weird enough. How many people have had adverse reactions to Quorn? The Center for Science in the Public Interest has collected more than 2,000 adverse-reaction reports since 2002. Chief complaints include nausea, vomiting, diarrhea, headache, sweating, stomach cramps, and difficulty breathing. But the health watchdog organization estimates that the real number of reactions may be much higher, since some consumers may not report symptoms, believing them to be food poisoning. A handful of trials and case studies have also documented adverse reactions like wheezing and shortness of breath, but none have drawn data from a sample size large enough to get definitive answers. Quorn itself reports that about 1 in 100,000 to 200,000 people will react badly to their products. If their claim to have served 3 billion meals is true, that means 15,000 to 30,000 have occurred thus far. So what’s causing the reactions? Hard to say. Quorn acknowledges that the product might cause digestive woes due to its high fiber and protein content. But the CSPI maintains that mycoprotein is causing allergic reactions in consumers. What’s the big deal? Plenty of foods cause allergic reactions or intolerance. Correct. But unlike soy, wheat, peanuts, and dairy, mycoprotein isn’t a well-known allergen. Plus, Quorn’s packaging doesn’t tell customers what mycoprotein actually is. You’d have to be an intrepid Googler to really understand the ingredient.   And the FDA is OK with all of this? Yup. They said so in a 2002 letter to Marlow Foods, in which they award mycoprotein their GRAS (Generally Regarded as Safe) stamp of approval. So what are we doing about it? The CSPI has been on the front lines of the Quorn debate since 2002, when they first reported on its potential to harm consumers. Since then, they’ve repeatedly implored the FDA to pull Quorn from American shelves, still to no avail. Litigation is now ongoing in the Center for Food Safety’s lawsuit against the FDA.  Will I react to Quorn? No one can say. But if you do, don’t forget to file a complaint with the CSPI.