Thursday March 1, 4:10 pm Eastern Time Leading US farm group demands Starlink-free corn seed WASHINGTON, March 1 (Reuters) - The American Farm Bureau Federation, the nation's biggest grower group, on Thursday urged farmers to demand corn seed for spring planting that is free of StarLink bioengineered corn. The Cry9C protein found in StarLink, a variety engineered to repel destructive plants, was discovered in other kinds of seed corn being readied for sale to farmers, industry and U.S. Agriculture Department officials said earlier Thursday. StarLink is approved only for animal feed, and not for human use because of concerns it might cause allergic reactions. ``Producers who are planning to plant corn this spring should check with their seed providers to ensure that the corn they plant does not contain the Cry9C protein,'' Bob Stallman, president of the American Farm Bureau, said in a statement. ``Producers should request certification that the seed corn they have on hand, or purchase for planting this season, has tested negative for the protein under the USDA's established testing protocol.'' Vast amounts of the U.S. corn harvest were accidentally contaminated with StarLink last year by elevators, grain handlers and farmers who failed to segregate the corn from other varieties. Aventis SA , the European-based maker of the corn, tried to buy back as much StarLink as possible last year. The company faces at least two lawsuits filed by Midwestern farmers who contend they were hurt by a drop in overall U.S. corn prices and exports caused by the flap. Some 17 states signed an agreement with Aventis in late January that requires the company to pay farmers and grain handlers for losses during the next four years. Japanese importers indicated in late February they might also take legal action against Aventis to seek compensation for costs of testing corn shipments to detect any contamination.