Genetically modified foods: breeding uncertainty

Environmental Health Perspectives, August, 2005 by Charles W. Schmidt

GM opponents have long argued that FDA consultations should be mandatory. But Jason Dietz, a consumer safety officer at the FDA's Center for Food Safety and Applied Nutrition, says that in the administration's view, the risks posed by transgenic crop breeding aren't great enough to warrant mandatory testing. Moreover, he adds, companies are liable for the health risks of GM foods under the safety provisions of the Federal Food, Drug, and Cosmetic Act.

The best way for companies to ensure their compliance with the act, Dietz says, is to undergo a premarket consultation with the FDA. "To our knowledge, all [GM] foods intended to be commercialized in the United States have been through the consultation procedure," he says.

An important and unresolved question is whether current testing methods will be adequate for second-generation crops. All the pest- and herbicide-resistance traits used now are found at minute levels in the plants, far below those likely to produce allergic responses, according to Taylor. But in some second-generation varieties, GM traits are intentionally expressed at high levels that change the nature of the food.

Taylor suggests that uncertainties about second-generation crop testing exacerbate the agrobiotech industry's reluctance to develop these markets further. "Because [the plant's] composition is significantly altered, and components are expressed at high levels, second-generation crops will probably require more extensive safety evaluation," he says. "One of the key issues is that there is no international agreement on what will be required. The uncertainty is considerable, and that creates hesitancy on the part of companies. Regulatory approvals will be less certain, consumer acceptance is a hurdle, and scientific uncertainty about how to proceed with safety assessment causes worry."

The Labeling Scene

In many countries, debates over GM foods have been accompanied by growing demands for an international labeling scheme to segregate transgenic and conventionally grown products. Labeling isn't required in the United States because regulatory agencies here don't view commercialized GM food as materially different from conventional varieties. However, the European Union does require it, and countries including Australia, Japan, and New Zealand, among others, have either established labeling systems or are in the process of doing so.

GM labeling is a tricky proposition that U.S. companies would rather avoid. Some surveys have shown that consumers are less likely to buy foods that they know are GM. Not only does labeling threaten markets, it could also be hard to implement, says Alan McHughen, a biotech specialist and geneticist at the University of California, Riverside. With few exceptions, most commodity crops grown in the United States aren't segregated once they reach the supply chain. Thus, both GM and conventionally grown nonorganic crops can wind up in the same containers as they make their way through distribution channels.