GEO-PIE Project: StarLink Corn

StarLink: GE corn in taco shells

StarLink, an unapproved variety of "Bt" corn, was first detected in taco shells in September, 2000. Estimates suggested it found its way into more than 50% of the US corn supply.

		On This Page: Headline: GE Corn in Taco Shells What is StarLink? How is StarLink different from other GE corn varieties? How did unapproved corn get into the food supply? The final word on Starlink?
Read more about GE insect resistance.		Headline: GE Corn in Taco Shells "StarLink," a variety of genetically-engineered corn not approved for human consumption, was initially detected in September of 2000 in Taco Bell taco shells distributed by Kraft Foods, Inc. The tests that identified the presence of StarLink were conducted for the watchdog group "Friends of the Earth" by Genetics ID, an independent testing lab. Kraft issued a voluntarily recall of the taco shells that might have contained processed StarLink corn. Subsequently, StarLink corn flour was detected in taco shells manufactured by Mission Foods of Irving, TX, which issued a voluntary recall of all of its products containing yellow corn. Because many Mission products are relabeled with store-brand packaging, taco shells produced by Mission for Safeway, Food Lion, Shaw's, and several other grocery chains have also been recalled. In the following months, Starlink was detected in a wide variety of yellow-corn products, many even outside the US. It has been estimated that as many as several hundred corn products may have been quietly recalled by individual manufacturers. StarLink, owned by France-based Aventis, was the only variety of genetically-engineered food marketed for animal feed but not approved for human consumption. Aventis had assured regulators that appropriate precautions would be taken by StarLink growers to prevent the GE corn from entering the food supply, but those precautions were apparently not adequate. Although Aventis agreed to purchase all of the remaining 1999 and 2000 harvests of StarLink corn, several million bushels of StarLink corn were unaccounted for, and probably entered the human food supply. Although Starlink represented only about 1% of the total corn harvest, estimates suggested Starlink may have contaminated as much as 50% of the year's corn harvest. Presently, most corn buyers and processors routinely test for the presence of Starlink corn. If it is still detected, the corn is sold for feed or non-food industrial uses. [top of page] What is StarLink? StarLink is a variety of genetically-engineered corn developed by Aventis Corp. to include two new traits, each coded by a different gene: 1) "Bt" based resistance to Lepidopteran caterpillar pests, such as the European Corn Borer, and 2) tolerance to glufosinate herbicides, such as Basta(TM), Liberty(TM), etc. StarLink is unlike other "Bt corn" varieties because it produces a modified version of the Bacillus thuringiensis (Bt) toxin protein, known as "Cry9C," an Aventis proprietary technology. [top of page] How is StarLink different from other GE corn varieties?
Read more about GE and food allergies.		If a genetically engineered (GE) plant produces a new protein, there may be some risk that the new protein could be an allergen to humans. For this reason, the FDA suggests that developers of new GE foods assess their potential allergenicity. If the source of a GE protein is a common, known allergenic food (such as peanuts), then allergy testing of the new GE food is relatively straightforward using standard clinical methods. If, however, the protein is from a source not normally in the food supply, then assessment of its potential allergenicity is much more difficult. Most known allergenic proteins have several chemical features in common (small size, resistance to heat, acid, and stomach enzyme digestion). The only available method of allergy assessment for "unknown" proteins is to subject them to similar chemical analysis.
Read the EPA's SAP findings here.		Bt-toxin proteins belong to the group of "unknowns." Because they are quickly degraded in the stomach, Bt-toxins have not been considered an allergy risk. However, tests submitted by Aventis to the EPA suggested that the Cry9C version of Bt-toxin in StarLink may be more heat-stable and digestion-resistant than other members of the Bt-toxin family-making it a higher risk for allergenicity. For this reason, the EPA did not initially allow the use of Starlink in human food. After the contamination of Starlink was detected in foods, Aventis petitioned the EPA to consider allowing the "temporary approval" of Starlink corn for human consumption, based on new data provided by Aventis. The EPA reviewed the new data and deferred to the advice of its scientific advisory panel (SAP). The SAP published its analysis on December 5, 2000-- concluding that Starlink does pose a moderate allergy risk. [top of page]
		How did unapproved corn get into the food supply? Regulators at first suspected that some StarLink growers may have ignored agreements not to sell StarLink corn to mills using the flour for human foods. Later interviews with growers, however, revealed that many farmers may not have been clearly instructed not to sell the corn for human use, or were told that the unapproved variety would be approved by harvest time. In the case of the Taco Bell-brand taco shells, Kraft Foods Inc. is licensed by Taco Bell to use the Taco Bell name on grocery-store taco shells. The taco shells were manufactured by Sabritas Mexicali in Mexicali, Mexico. The corn flour was purchased by Sabritas from Azteca Milling, which mills corn in Plano, Texas. Azteca purchases corn from growers in a six state area in the US southwest. It is unknown at which point in the supply-line the corn was contaminated with StarLink, but it appears that many farmers simply sold the unapproved corn directly to the mill. Mission Foods, producer of the Safeway taco shells, also purchases corn flour from Azteca Milling. Although Starlink corn was less than 1% of the total 1999 and 2000 corn harvests, mixing of Starlink with other corn varieties at individual mills may have caused a disproportionately larger number of corn products to be contaminated. [top of page] The final word on Starlink? After the discovery of Starlink contamination, two dozen people came forward claiming that they had had severe allergic reactions after eating corn products containing Starlink corn. Seventeen of the 24 allowed blood samples to be tested by the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention. The CDC released a report on June 13, 2001, concluding that although the claimants did appear to have had severe allergic reactions to something, blood tests demonstrated that they were not allergic to Starlink. To date, there have been no documented cases of allergic reactions to Starlink corn. On July 19, 2001 the EPA's scientific advisory panel (SAP) determined that although the CDC/FDA findings demonstrates that those individuals were not allergic to Starlink, it should not be used to conclude that no one could be allergic to Starlink-- this new evidence did not affect the earlier advisory panel findings of moderate potential allergenicity of Starlink (SAP: December 2000, see above). Furthermore, the SAP admonished the FDA and CDC to more actively investigate the possibility of other unreported cases of allergic reactions. Following the advice of its SAP, the EPA ruled on July 27, 2001, that it would not accept Aventis' petition to allow traces of Starlink to remain in the food supply, and that its policy of zero tolerance would continue. [top of page] References FDA. 1992. Statement of policy: Foods derived from new plant varieties; Notice. Federal Register 57:22984-23005. Friends of the Earth. Press Release: September 18, 2000. See http://www.foe.org/act/getacobellpr.html. Kraft Foods Inc. Press Release: September 22, 2000. See http://www.kraftfoods.com/special_report. Metcalf, D., Astwood, J., Townsend, R., Sampson, H., Taylor, S., Fuchs, R. 1996. Assessment of the allergenic potential of foods derived from genetically engineered crop plants. Critical Reviews in Food Science and Nutrition 36(S):S165-S186.