TAMPA — A large, illuminated sign protesting a federal farming law was posted on an overpass early Wednesday, and a protest organizer says commuters haven't seen the last of it.The sign was reported to the Florida Highway Patrol about 6:30 a.m. Troopers responded to the Interstate 4 overpass near U.S. 301 but did not remove it because it was not disrupting traffic. About 7 a.m., protesters began removing the sign, which said, "Stop Monsanto GMO Law."That's a reference to a wide-ranging appropriations bill that Congress recently passed and that President Barack Obama signed last week.New York Times food columnist Mark Bittman reported in an online blog this week that one section of the bill "essentially prohibits the Department of Agriculture from stopping production of any genetically engineered crop once it's in the ground, even if there is evidence that it is harmful."Critics say it provides excessive legal cover to agri-tech companies like Monsanto, a Fortune 500 company based in St. Louis, that work with genetically engineered foods."Our mission is to try to put a stop to this Monsanto protection act," said protest organizer Kyle Petillo, 30, of Plant City. "It's really something that snuck in under the radar."The dozen or so protesters responsible for Wednesday's demonstration came together through the Facebook page, "March Against Monsanto." Petillo said he believes people have a right to eat naturally grown food, as opposed to genetically modified food, and to know when food was grown from genetically modified seeds or similar products.On its website, Monsanto defends the provision, saying it strikes "a careful balance allowing farmers to continue to plant and cultivate their crops subject to appropriate environmental safeguards, while USDA conducts any necessary further environmental reviews."The company also denies that the provision was slipped into the bill in secret, noting that a coalition of cotton, corn, soybean, wheat, sugar beet and other farming groups wrote to Congress last June in public support of the provision.Petillo said the group plans to return to the overpass early April 11 with a similar protest. It also plans a rally on genetically engineered crops at 8 a.m. April 28 at Edward Medard Regional Park in Plant City."What we're trying to do is raise awareness," he said.Times researcher John Martin contributed to this report.