The StarLink Corn Episode

StarLink was a Bt corn variety carrying the Cry9C protein, approved by the EPA in 1998 for animal feed and industrial use only. Cry9C digested slowly and withstood heat better than other Bt proteins, which raised an unresolved question about allergenic potential in humans. The EPA’s answer was a split approval, the only one of its kind: legal to grow, illegal to eat.

Split approvals assume corn stays where it is put. Corn does not. In September 2000, a coalition of advocacy groups had taco shells tested and found Cry9C DNA. Kraft recalled millions of boxes. Aventis, the trait’s owner, bought back the entire StarLink harvest. Japan and South Korea suspended purchases of U.S. corn, and export prices sagged under the uncertainty. StarLink had been planted on well under one percent of U.S. corn acres, yet its protein turned up in roughly a tenth of tested grain lots, a spread driven by cross-pollination, shared combines, elevators, and every other place bulk grain mingles.

The seed industry’s turn came that winter. On December 28, 2000, USDA’s Grain Inspection, Packers and Stockyards Administration wrote to seed corn companies recommending that all seed corn for the 2001 planting season, and all parent lines for 2001 seed production, be tested for Cry9C. The industry alert relaying that letter went out the next day and was hosted on this domain; Purdue Extension’s pest and crop newsletter linked it that spring, and the link survives in Purdue’s archives today.

The lasting changes outlived the recall. Trait testing of seed lots became routine commercial practice rather than an emergency measure. Split food-feed approvals were abandoned; no U.S. trait since StarLink has been approved for feed but not food. And the episode handed the industry its defining lesson about adventitious presence: in a bulk commodity system, a trait planted on one field in a hundred will be found everywhere you look for it. That lesson drives the seed purity work covered in our adventitious presence resource.

Cry9C monitoring in the U.S. grain supply continued for years afterward, with positive tests declining steadily before ending in the mid-2000s. StarLink itself was never replanted; its registration was withdrawn in 2000.