In April 1996, as Britain was swept up in a national panic over mad cow disease -- a sickness diagnosed in U.K. cattle that has been linked to a handful of cases of Creutzfeldt-Jakob disease in humans -- Oprah Winfrey devoted an episode of her widely popular show to the threat that the disease posed to cows and people on this side of the Atlantic.Winfrey is hardly known for her nuanced, dispassionate examination of the issues of the day, and this episode was no exception. Howard Lyman of the Humane Society's Eating With A Conscience campaign, one of Winfrey's guests, argued that the U.S. beef industry's practice of feeding cows the ground-up remains of other cows could lead to an outbreak of mad cow disease in the United States. In fact, Lyman warned the show's millions of viewers, the United States was heading toward a tragic epidemic."You said this disease could make AIDS look like the common cold?" Winfrey gasped."Absolutely," said Lyman.Gary Weber of the National Cattlemen's Beef Association and William Hueston of the Department of Agriculture argued that feeding rendered cows to other cattle was perfectly safe, but Winfrey emphatically sided with Lyman. "It has just stopped me cold from eating another hamburger," she said to audience applause. "I'm stopped!"Cattle prices plummeted the next day, and dropped 10 percent by the end of May. Just days after the show aired, Texas Agricultural Commissioner Rick Perry called for action under a year-old state law banning disparaging remarks against perishable food. One of 13 states that have enacted so-called "veggie- libel" laws, Texas allows growers and ranchers to sue critics for damages suffered as a result of claims about agricultural products not grounded in "reasonable and reliable scientific inquiry, facts or data."Texas' attorney general chose not to pursue the matter, but a group of ranchers, led by Amarillo cattleman Paul Engler, filed suit privately in June 1996. The ranchers charged that the show's "carefully and maliciously edited statements that were designed to hype ratings at the expense of the American cattle industry."The case marks the first and only suit to be filed to date under a food- disparagement law. Proponents of these laws argue that the public needs to be protected from mavericks who make outrageous claims about the dangers of modern food technologies. "Part of the incentive is to, at least, get someone to think twice before making an accusation," says Steve Kopperud, vice president of the American Feed Industry Association (AFIA). "The producer community and others have grown increasingly concerned by food scares that hit the media through activists with the price of an ad in a major publication."Critics, however, assert that food-disparagement laws tip the scales too far in favor of the food industry and do significant harm to free speech rights. They are also concerned that the laws will make it harder for those outside the scientific establishment to question products and practices that they consider unsafe.The nation's first food-disparagement law, passed in Colorado in 1991, was pushed through by a state legislator who claims he lost his farm due to the scare over Alar, a chemical used by apple growers to lengthen ripening time. In 1989, the Natural Resources Defense Council (NRDC) reported that Alar breaks down into a carcinogen dangerous to children. 60 Minutes aired an Alar expose, and public service announcements featuring Meryl Streep warned that the chemical was present in juice bottled for children. The public panicked, causing the apple industry to lose more than $100 million in sales, according to industry estimates.A group of Washington state apple growers sued CBS and the NRDC for libel in 1990, insisting that Alar was safe. The growers lost their case in court, but the food industry regained the legal upper hand when Colorado passed its food-disparagement statute.Although the AFIA did not have a role in creating the Colorado law, it was quick to pick up the idea and run with it. On the association's behalf, Washington, D.C., law firm Olsson, Frank and Weeda has been circulating a model food-disparagement bill to state legislatures around the country since 1991. Individual corporations have also been lobbying hard for these laws. In one example, Bill Hargraves of the irradiation company Food Technology Service Inc. sent a copy of Florida's food-disparagement law to Hawaii Department of Agriculture official Lyle Wong in August 1995. At the time, Hawaii was considering a controversial plan to kill bacteria by irradiating fruits and vegetables. "You may want to encourage the Hawaiian legislature to enact something similar since it might help muzzle the anti's," Hargraves wrote.Seattle lawyer Bruce Johnson, who defended CBS in the Alar case, says the food-disparagement laws are unconstitutional because they violate existing standards that demand that a person must act with reckless disregard for the truth for speech regarding matters of public concern to be considered libelous. But in 1995, a Georgia court dismissed an American Civil Liberties Union legal challenge to the state's food-disparagement law because no relevant case was in litigation. Until the courts weigh in on the law's constitutionality, says David Bederman, an Emory University law professor who represented the ACLU in that case, local activists will remain anxious about what they can print in their own newsletters."Laws like this chill speech," he says. "People change their behavior out of fear that what they say will make them liable." He warns that the laws don't only silence fringe ideas; they ban any claims that are not based on reasonable and reliable scientific inquiry, facts or data. "This punishes scientists and investigators at the leading edge," he says. "The first person to publish in a peer review journal a new discovery, a new link, a new theory, is going to be at risk of getting sued."Science evolves as new ideas are debated, tested and then are either refuted or become the new conventional wisdom. Lyman's comments on Oprah turned out not to be so far-fetched. "Everything that Howard Lyman said or what Oprah said on the show is completely defensible and in-bounds," says John Stauber of the Madison-based Center for Media and Democracy and author of a forthcoming book on mad cow disease. After its initially nonchalant response, the Food and Drug Administration drafted a rule in January that, if adopted, would ban fortifying animal feed with cow renderings. Likewise in the Alar case, the Environmental Protection Agency classified the chemical as a probable human carcinogen this year.Law or no law, the food industry continues to throw its weight around. Olsson, Frank and Weeda, the firm that circulated the model libel bill, sent a "cease and desist" warning to Food & Water, a grassroots group based in Vermont. The letter, sent on behalf of the United Fresh Fruit and Vegetable Association, threatened to sue the group for libel if it did not halt its campaign calling on food distributors not to carry irradiated produce.Food & Water executive director Michael Colby thinks the industry is bluffing. "Stop threatening us and take it to the next level," he says. "We'd love to show how ridiculous the FDA approval was for some of these things. Anyone with a lick of common sense knows that there are health and environmental concerns with exposing the food supply to nuclear radiation."As Colby waits for industry lawyers to make their next move, the Oprah case wends its way toward a trial. In the interim, people like Ronnie Cummins, director of the Pure Food Campaign in Washington, D.C., are on tenterhooks. He worries that a financially crippling lawsuit -- whatever the outcome -- would destroy his group.You need to look no further than Winfrey, Cummins says, to see how food- disparagement laws affect activism. "Oprah said she got more letters and phone calls from that program than any other in the history of her show," he says. But the lawsuit has taken the wind out of her sails. "She went from being very outspoken on the issue to literally saying nothing."