Even though genetically modified "StarLink" corn is no longer on the market, growers and grain elevators are still grappling with StarLink contamination in their seeds and silos.
As this ScienCentral News video report shows, efforts to contain the banned corn reveal how hard it is to keep biotech crops out of the food supply.
What is StarLink?
StarLink is a type of corn that is genetically modified to produce its own pesticide by expressing the gene for a toxin from the naturally occurring bacteria bacillus thuringiensis, or "Bt." The toxin kills a yield-munching pest, the European corn borer, which is very hard to combat with sprayed pesticides because the corn borers live and feed inside the cornstalks. The Environmental Protection Agency (EPA) approved Bt corn in August 1995 and, according to the US Department of Agricultures Economic Research Service, "its use grew from about 1 percent of planted corn acreage in 1996 to 19 percent in 1998. It peaked at about 26 percent in 1999 before falling to 19 percent in 2000."
StarLink is the only type, or "event" of Bt corn that is not approved for human consumption. In 1998, the EPA approved it only for use in animal feed or ethanol production. That is because the Bt protein in the corn, Cry9C, was similar enough to some known food allergens to prompt concerns that it might also cause allergic reactions. Cry9C is a much larger molecule than the more commonly used Bt event, Cry1C, which makes it harder to digest, giving the body more time to react to it.
The split approval required growers of StarLink to keep their harvest out of the human food market, and to plant 660 foot borders of non-StarLink corn around their fields to prevent cross-pollination of their neighbors fields with StarLink pollen. Many growers now say the company that made StarLink seeds, Aventis Crop Science did not do enough to inform them of the restrictions. They brought their corn to local elevators, where it was mixed with yellow corn sold to food producers. When a group of activists opposed to genetically modified food found StarLink in Taco Bell taco shells last fall, hundreds of products containing the unapproved corn were recalled.
Aventis voluntarily revoked its registration for StarLink, so no more of it will be sold. The EPA has announced that "the type of split pesticide registration, which approved StarLink to be used solely for animal feed, will no longer be considered a regulatory option for products of biotechnology."
Thirty-four individuals who reported having allergic reactions after possibly eating products containing StarLink, had their blood drawn by the Centers for Disease Control (CDC), to be tested for antibodies to Cry9C. The results of those tests are expected to be released this summer.
For information on the effects of Bt corn pollen on Monarch Butterflies, see STN2s report.