Safe Food: The Politics of Food Safety Read Online Free PDF Page B

Ovals indicate corporate ownership. The diagram reveals the difficulties of keeping StarLink corn separated from conventional corn during growth, harvest, storage, and processing.
    *Tricon Global changed its name to Yum! Brands, Inc. in 2002.
The Safety Issue: Allergenicity
    The driving force behind these events was the idea that some people might be allergic to the StarLink protein. Food allergies, although rare, can be extremely dangerous and sometimes fatal to susceptible individuals. In the months following the taco shell disclosure, the Food and Drug Administration (FDA) collected accounts from people who said they experienced allergic reactions to products made with StarLink corn, and the EPA asked its Scientific Advisory Panel to advise the agency about scientific issues related to the allergenicity of the StarLink protein.
    The panel’s responses to the EPA surely constitute the most thorough evaluation of a food allergen ever conducted and provide a vivid example of how difficult it is to make policy decisions based on science that is incomplete and uncertain (which so often is the case). Panel members said they were “uncomfortable with the available data” and did not have enough information to decide whether the StarLink protein could cause allergic reactions. They knew that proteins are strings of amino acids arranged in a particular sequence, and that whether a protein provokes an allergic response depends on how that sequence folds—its structure and shape. Only some proteins are allergenic, but it is not yet possible to predict the structural features that induce allergic reactions. The panel members had to make educated guesses about the size, digestibility, and stability to heat of the Cry9C protein, and about the prevalence of this protein in the food supply.
    One reason the Cry9C protein is toxic to insects is that they cannot easily digest it—break it down—to its constituent amino acids; the structureof the protein survives the digestive processes more or less intact. The Cry9C protein also is relatively stable to heat, so cooking might not destroy its ability to cause allergic reactions. Furthermore, preliminary feeding studies showed that the Cry9C protein appeared intact in the blood of rats and provoked immune responses, meaning that rats could not digest it and destroy its allergenicity. No such studies had been conducted in humans, however. Thus, panel members could not dismiss the possibility that the StarLink protein
might
be allergenic to humans. They judged the StarLink protein to have a “medium” likelihood of being allergenic, mainly because its potential to induce allergic reactions could not be disproved. Because processing and cooking were likely to destroy some of the Cry9C proteins, and the amounts were quite small to begin with, they judged Cry9C to have a “low” probability of actually causing allergic reactions in the population. These judgments supported the EPA’s precautionary decision not to allow StarLink to enter the human food supply. 5
    A further complication is the question of whether people actually experience allergic reactions when they eat StarLink products. As it turns out, this connection is not easy to prove. Just because people feel sick after eating a food does not necessarily mean that the food—and not something else—caused the illness. Finding the StarLink
gene
in a food does not necessarily mean that the protein it specifies will cause allergic reactions. Like other genes, the StarLink gene is made of DNA (deoxyribonucleic acid), and its constituent components are common to all living species (see appendix). DNA and genes do not induce allergic reactions, but they specify the structure of proteins. Proteins (but not all of them) cause allergies. To prove that the StarLink protein is allergenic, scientists have to show that people reporting allergic reactions ate foods containing the StarLink corn protein and displayed immune responses to the