(Excerpt from: Assessing the safety and nutritional quality of genetically engineered foods by John Fagan)

In 1994, the US Food and Drug Administration, Environmental Protection Agency, and the Department of Agriculture hosted a "Conference on Scientific Issues Related to Potential Allergenicity in Transgenic Food Crops." The scientists selected by these agencies to attend this meeting and to advise them on the issue of allergenicity of genetically engineered foods indicated that it is likely that the use of recombinant DNA techniques in developing new crop varieties carries with it a significant possibility of generating unanticipated allergens.

They further pointed out that this is quite problematic for safety testing. While methods are available to assess whether a genetically engineered food contains hazardous amounts of known allergens, there are no direct or comprehensive methods for assessing the potential allergenicity of proteins derived from sources that are not known to produce food allergies. Scientists are reduced to comparing the general characteristics of such proteins to proteins that are known to cause allergic reactions, rating their similarities in terms of characteristics such as amino acid sequence, resistance to enzymatic or acidic degradation, heat stability, and molecular weight. These are of course extremely general characteristics and are unlikely to yield definitive information regarding the ability of a protein to elicit a biological reaction as complex as the immune response.

In this situation, the only viable approach to eliminating significant risk of allergenicity in a new transgenic food is to require that human testing be carried out before commercialization, and that commercialization be accomplished in two phases, a limited test market phase which includes careful monitoring of potential allergenicity, followed by full scale commercialization. This strategy assures that all except extremely rare allergens will be detected before the public is widely exposed to a new transgenic food.