Questions About Starlink ®

This information was provided by
the Institute of Food Technologists - Chicago, Illinois

What is Cry9C, the controversial protein in Starlink ® corn?
Cry9C is an insecticidal protein added through genetic modification to certain corn hybrids to control the European and Southwestern corn borers and to suppress black cutworm. Cry9C was isolated from a common soil bacteria, Bacillus thuringiensis (Bt) sp. tolworthi. Like the Cry1A insecticidal protein in many other insect-resistant corn varieties, Cry9C kills insects by destroying their stomach cells. However, Cry9C binds to a different site in the gut, offering the potential to manage insect resistance to Bt-based insecticidal products.

Is the Cry9C protein an allergen?
Scientists are still investigating whether the Cry9C protein is an allergen, but no definitive evidence has indicated that it is. Based on the limited available evidence, the EPA Scientific Advisory Panel said there was a 'medium' risk that the protein was a potential allergen. Because the amino acid sequence of the Cry9C protein is not similar to known allergens, the protein does not have a high likelihood of allergenicity. However, the protein met 'to some degree' the additional six risk factors for allergenicity established by a previous panel:

1. The protein is relatively resistant to acid treatment.
2. The protein is relatively resistant to breakdown by digestive enzymes.
3. The protein size is in the general molecular weight range for an allergen (10-70 kD).
4. The native protein is probably a glycoprotein.
5. The protein (isolated or in corn) induces an immunologic response in Brown Norway rats.
6. The protein may be found intact in the bloodstream after oral feeding in the rat model.

The EPA panel called for additional data to better assess whether these risk factors were applicable to the Cry9C protein.

Is it safe to eat food that may contain Starlink ® corn?
Many scientists believe that for people to become allergic to a protein, they must be exposed to it multiple times over an extended period until they become sensitized. Also, allergenic proteins are usually present at a relatively high percentage of the total protein content. According to an analysis conducted by the corn's manufacturer, the Cry9C protein represents only a small fraction of the corn protein. After considering all the available evidence, the EPA SAP concluded that at the very small amounts of the Cry9C protein present in today's food supply, the probability that the protein would sensitize some individuals is low.

If it is safe, why are products being recalled?
The products are subject to recall requirements simply because they contain a substance that has not been approved for human food. FDA has created a tiered system of food recalls, based on the severity and likelihood of potential adverse medical consequences as a result of the recalled product.

The recall that initiated the removal from the market foods that are contaminated with Starlink ® corn was a Class II recall. This type of recall is initiated when a product may cause temporary or medically-reversible adverse health consequences, and the probability of serious adverse health consequences is remote. This recall classification was assigned based on the evidence that the extremely small amount of Starlink ® corn present in the recalled foods does not pose a serious health risk to consumers.

Foods that have a reasonable probability of causing serious adverse health consequences or death would fall under the Class I recall procedures. A Class III recall is initiated for products that are not likely to cause adverse health consequences.

Has consuming Starlink ® corn made anyone ill?
Although FDA has received approximately 34 reports of adverse reactions, 20 of those reports have already been classed as very unlikely to be the result of an allergic reaction.

U.S. Center for Disease Control and Prevention is researching a group of 7 people who experienced symptoms consistent with an allergic reaction after eating a meal that contained corn. However, it is not known if the Cry9C protein was present in the corn products that were consumed. In addition, the presence of other allergens within the meal has not been ruled out. Another 7 individuals experienced reactions that were less likely to be allergic reactions, but data were insufficient to rule out an allergic reaction. CDC continues to investigate those cases.