StarLink

J. Lynne Brown
Associate professor of Food Science

What is StarLink?

StarLink is one type of genetically engineered field corn. Farmers grow field corn for the animal feed market. StarLink was developed by Aventis CropScience, a branch of the French biotechnology company, Aventis SA. StarLink corn contains the gene, Cry9C, for a toxin that kills insects like the European corn borer. Cry9C comes from a common soil bacterium called Bacillus thuringiensis (Bt).

Why were taco shells recalled?

Mission Foods (Safeway) and Taco Bell (Kraft Foods) taco shells were recalled in September and October 2000 because they contained small amounts of DNA from genetically engineered corn. In addition, the Taco Bell chain replaced taco shells in all 7,000 of its restaurants. This was a Class II recall, used when a food has an adulterant but does not pose a serious risk to human health.

Genetically Engineered Food Alert, a coalition of consumer and environmental groups, had some of these shells tested by an independent testing laboratory. The laboratory found the DNA or gene for Cry9C in these taco shells in very small amounts-1 percent of the corn DNA present. Taco shells for human consumption should not contain any Cry9C genes. When FDA confirmed the findings of the independent testing laboratory, Safeway and Kraft instituted Class II recalls of the contaminated food products. More information can be found at http://www.kraftfoods.com or at 1-800-433-9361.

What is Cry9C?

Cry9C is a gene from a common soil bacterium. The Cry9C gene is used by the bacterium to make a protein called a pro-toxin. If a chewing insect eats this pro-toxin, the juices in its stomach convert the pro-toxin to an active toxin that kills the insect.

Why is Cry9C not supposed to be in taco shells that we eat?

When Aventis developed StarLink, which contains the Cry9C gene, they consulted the EPA about its safety. Aventis provided information to the EPA about how quickly the Cry9C protein was broken down in conditions like those in the human stomach. The Cry9C protein was still intact after 30 minutes of exposure to stomach acids and digestive enzymes, whereas other proteins broke down completely by 7 minutes. The Cry9C protein's resistance to digestion suggested it could act like an allergen. Further tests would be needed to determine whether this protein was an allergen. So EPA approved the use of StarLink for animal feed but not for human consumption.

How did the Cry9C gene get into the Taco shells?

The flour for the Safeway (Mission Foods) and Kraft (Taco Bell) tortillas came from one mill belonging to Azteca Milling in Plainview, Texas. Azteca buys corn from farmers in six states. Azteca is the largest producer of corn flour for use in tortillas and tacos in the United States and is a unit of Texas food producer, Gruma Corp, a subsidiary of the Mexican food group Gruma. Mission Foods, based in Irving, Texas, is the largest tortilla maker in the United States and makes private-label products for supermarkets as well. Kraft buys its shells from a factory in Mexicali, Mexico, owned by Sabritas, a subsidiary of PepsiCo, that receives its corn flour from the Azteca Mill in Plainview, Texas. Officials suspect the contaminated corn entered the system through corn sold to the Azteca Mill in Texas, but no one knows for sure.

How does the Cry9C gene cause allergies?

The gene itself does not cause allergies. The protein made from the gene might cause allergies if sensitive individuals are exposed to the protein often enough. Allergies are thought to develop if nearly intact proteins make it through the stomach and into the small intestine, although the mechanism is not clear at this time. There the proteins may pass through the intestinal wall and into the lymph system where antibodies may be formed that lead to the allergic reaction. Only the DNA was found in the initial tests done on the taco shells.

How did Aventis inform farmers about keeping this corn out of food for humans?

Aventis sold StarLink seed to farmers to plant this past year. The company said it required farmers who bought the seed to sign agreements saying they would use the corn only for animal feed or industrial use, and they would keep a 660-foot buffer strip to prevent StarLink from spreading its genes to other corn during pollination. About 0.5 percent of U.S. corn acreage was planted with StarLink in 2000. Some farmers who bought StarLink reported they were not told the corn was unfit for human consumption or did not receive written instructions to keep buffer strips. Because seed is often sold by farmer representatives who may not emphasize the restrictions, farmers may miss meetings in which restrictions are discussed or farmers who work long hours may just miss written instructions. Whatever the reason, some StarLink got mixed in with other corn for human consumption.

What is Aventis doing to correct the situation?

Aventis is buying back segregated StarLink corn from farmers and elevators at a premium of 25 cents a bushel. However, they have refused to buy the far-larger quantity of corn that may have gotten mixed with StarLink. They claim to have traced and recaptured 87-88 percent of the corn harvested leaving 12 percent or 9 million bushels, which appears to have entered the food-processing chain. Aventis has agreed to help farmers who did not plant StarLink but who have found their corn harvest contaminated with StarLink by cross-pollination.

Aventis voluntarily canceled its registration and thus its license to sell StarLink, so that no more of the corn can be sold or enter the food system. However, Aventis has requested that EPA allow the use of StarLink in human food for four years saying that new studies demonstrated "reasonable certainty" of no harm to consumers. On April 23, 2000, in recognition that EPA is unlikely to approve this, Aventis asked the EPA to instead set an upper limit (20 parts per billion) for the Cry9C protein in corn delivered to mills. This upper limit, also called a tolerance, corresponds to the detection limit of the strips now being used to test corn delivered to mills. Mills would continue to test all incoming corn.

Aventis SA., the parent company of Aventis CropScience, plans to sell the agricultural division in the near future, abandoning plans to sell seeds and pesticides as well as medicines.

What federal agency is responsible for regulating this corn?

EPA regulates pesticides even when a plant produces the pesticide itself. Therefore, Aventis consulted with EPA to establish StarLink's safety before selling it.

What is EPA doing to handle this situation?

EPA urged Aventis to voluntarily revoke its marketing license to sell StarLink. Aventis provided new information to EPA in November 2000 to support a request to allow this corn to be temporarily approved for human consumption. The company believes it will take about four years for StarLink corn in the food system to work its way through grain elevators, flour mills, and food manufacturing plants to the ultimate consumer.
EPA held a public, scientific advisory meeting November 28 and 29, 2000, to consider the new information provided by Aventis, as well as comments from the public and industry. The company feels that the StarLink protein is present in such low amounts that people will not be exposed to enough to develop allergies and pointed out that the Cry9C protein structure does not appear similar to that of other known allergens. EPA also allowed a month for public comments about the four-year request by Aventis.

Evidence presented at that meeting found extremely low amounts of the protein in foods. However, the amount that would trigger allergic reactions is not known. An industry organization presented evidence that the protein was broken down in laboratory tests designed to simulate food-processing conditions. The scientific panel reported there was a "medium likelihood" that the Cry9C protein was a potential allergen, but there was a low probability that allergy problems will arise because there is so little StarLink in the food supply.

What are grain elevator operators doing about the contaminated corn?

Big grain elevator operators and millers are testing loads of corn arriving for purchase for StarLink. Farmers who try to sell contaminated loads are generally directed to find cattle feedlots or ethanol producers for their corn. ConAgra closed one of its mills to check for StarLink contamination and to clean their mill. Both grain processors and farmers are facing the need to segregate genetically engineered grain from conventional grain, something the system is not equipped to do. Aventis has supplied testing kits to grain elevators and processors around the country. DuPont also released a test kit for genetically engineered DNA in food samples.

How has this affected food manufactured using corn flour?

In October 2000, the Kellogg Co. stopped production of some of its products in a Memphis, Tennessee plant because the mill that supplied its corn flour had shut down to check for StarLink corn. Kellogg produces Frosted Flakes and Special K cereals, among others. In October 2000, ConAgra Foods Inc., the country's second-largest food manufacturer, reported it had suspended milling operations at its corn processing plant in Kansas while it tests for StarLink corn.

Has the contamination moved beyond the United States?

On October 25, 2000, a Japanese consumer group reported the detection of Cry9C in cornmeal manufactured in Japan. In January 2001, the Japanese Ministry of Health reported finding traces of StarLink in corn shipped from the United States to Japan. StarLink is not approved for use in Japan, even in animal food. The Japanese government has asked for products containing StarLink to be withdrawn from the market as a preventative measure. In 1998-99, Japan imported 15.4 million tons of American corn, accounting for $1.5 billion of the $5 billion in total corn exports from the U.S. Corn sales to Japan, South Korea, and other countries declined in the weeks after StarLink was detected.

What else has happened as a result of this contamination?

• A class action, negligence suit was filed on December 4 against Aventis on behalf of farmers who planted StarLink.
• Tyson, one of the nation's largest poultry producers, has announced it will not accept any corn contaminated with StarLink for feeding its chickens. Tyson will leave it to their suppliers to ensure the corn they sell is free of StarLink. Tyson buys about 6.3 million bushels of corn each week.
• USDA has asked for public comment on a proposed rule to ensure strict segregation of gene-altered crops, such as StarLink corn. The document, known as an advance notice of proposed rulemaking, will be published in the Federal Register sometime in November 2001.
• Seed companies have discovered traces of StarLink in small amounts of seeds meant for sale to farmers. On March 2, 2001, the Department of Agriculture asked the members of the American Seed Trade Association for an accounting of the amount of seed corn contaminated with StarLink.
• In March 2001, Greenpeace reported that Kellogg's Morningstar Farms meat-free Corn Dogs contained StarLink corn. Kellogg's sent samples of this product to an independent laboratory for testing. On March 13, 2001, the Kellogg subsidiary Worthington Foods announced it was voluntarily recalling Morningstar Farms products (veggie Corn Dogs and Mini Corn Dogs) because they are contaminated with StarLink corn based on Kellogg's own test results. The contamination was apparently due to a mistake by the company supplier.
• In March 2001, EPA announced it will no longer award any pesticide registrations that approve a genetically engineered product for animals but not for humans. EPA also released a paper describing how food processing affects the levels of Cry9C protein in the finished food. If the StarLink corn undergoes wet milling, 'essentially no residues of the Cry9C protein are detectable in the finished food. But food products made from dry milled corn can contain the Cry9C protein.

References

Ament, L. and M. E. Butler. Unapproved variety of GM corn found in Safeway taco shells. Food Chemical News 42 (35), October 16, 2000.

Anonymous. Kraft recalls Taco Bell shells with biotech corn. Reuters. September 24, 2000.

USDA seeks advice on its role in bio-grain segregation. Reuters. October 27, 2000.

Arasu, K. T. Tyson stops buying StarLink gene-altered corn. Reuters. October 20, 2000.

Barboza, D. Negligence suit is filed over altered corn. New York Times, December 4, 2000.

Barboza, D. Gene-altered corn changes dynamics of grain industry. New York Times, December 11, 2000.

Becker, E. New worries of planting altered corn. New York Times, March 2, 2001. C3

Bloomberg News. Aventis to sell agricultural unit. New York Times, November 16, 2000.

Bloomburg News. Genetic worries hurt U.S. corn sale abroad. New York Times, November 17, 2000.

Feder, B. J., Farmers cite scare data in corn mixing. New York Times, October 17, 2000.

Kaufman, M. Biotech critics cite unapproved corn in taco shells. Washington Post, September 18, 2000.

Kaufman, M. Corn woes prompt Kellogg to shut down plant. Washington Post, October 21, 2000.

Pollack, A. Safeway recalls taco shells after test questions corn origin. New York Times, September 12, 2000.

Pollack, A. The Taco Bell brand of shells contains bio-engineered corn that is not approved for humans. The Associated Press. September 23, 2000.

Pollack, A. Labeling genetically altered food is thorny issue. New York Times, September 26, 2000.

Pollack, A. Aventis gives up license to sell bioengineered corn. New York Times, October 13, 2000.

Pollack, A. New choice for FDA on engineered corn; company is likely to seek easing of the ban on product in food. New York Times, October 25, 2000.

Pollack, A. Corn developer appeals to EPA. New York Times, October 26, 2000.

Pollack, A. Plan for use of bio-engineered corn in food is disputed. New York Times, November 29, 2000.

Pollack, A. Federal panel is wary of gene-altered corn. New York Times, December 6, 2000.

Strom, S. Bioengineered corn reportedly detected in Japan. New York Times, October 26, 2000.

Strom S. Altered U.S. corn found in samples sent to Japan. New York Times, January 18, 2001.

Vorman, J. EPA sets November meeting on StarLink corn. Reuters. October 30, 2000.

Osvath, R. StarLink corn in Kellogg's products, Greenpeace says. Food Chemical News, 43 (4) March 12, 2001.

Osvath, R. Split biopesticide registrations to be stopped by EPA. Food Chemical News, 43 (4), March 12, 2001.

Osvath, R. Kellogg's subsidiary recalls products containing StarLink corn. Food Chemical News, 43 (5), March 19, 2001.

Pollack, A. Aventis tries a new tack on StarLink Corn. New York Times, April 24, 2001

Penn State College of Agricultural Sciences research, extension, and resident education programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U. S. Department of Agriculture.

Where trade names appear, no discrimination is intended, and no endorsement by the Penn State College of Agricultural Sciences is implied.

Issued in furtherance of Cooperative Extension Work, Acts of Congress May 8 and June 30, 1914, in cooperation with the U. S. Department of Agriculture and the Pennsylvania Legislature. T. R. Alter, Director of Cooperative Extension, The Pennsylvania State University.

This publication is available in alternative media on request.

The Pennsylvania State University is committed to the policy that all persons shall have equal access to programs, facilities, admission, and employment without regard to personal characteristics not related to ability, performance, or qualifications as determined by University policy or by state or federal authorities. The Pennsylvania State University does not discriminate against any person because of age, ancestry, color, disability or handicap, national origin, race, religious creed, sex, sexual orientation, or veteran status. Direct all inquiries regarding the nondiscrimination policy to the Affirmative Action Director, The Pennsylvania State University, 201 Willard Building, University Park, PA 16802-2801: Tel. (814) 865-47