Characteristics and safety assessment of intractable proteins in genetically modified crops.
A number of genetically modified (GM) crops bioengineered to express agronomic traits including herbicide resistance and insect tolerance have been commercialized. Safety studies conducted for the whole grains and food and feed fractions obtained from GM crops (i.e., bioengineered foods) bear similarities to and distinctive differences from those applied to substances intentionally added to foods (e.g., food ingredients). Similarities are apparent in common animal models, route of exposure, duration, and response variables typically assessed in toxicology studies. However, because of differences in the nutritional and physical properties of food ingredients and bioengineered foods and in the fundamental goals of the overall safety assessment strategies for these different classes of substances, there are recognizable differences in the individual components of the safety assessment process. The fundamental strategic difference is that the process for food ingredients is structured toward quantitative risk assessment whereas that for bioengineered foods is structured for the purpose of qualitative risk assessment. The strategy for safety assessment of bioengineered foods focuses on evaluating the safety of the transgenic proteins used to impart the desired trait or traits and to demonstrate compositional similarity between the grains of GM and non-GM comparator crops using analytical chemistry and, in some cases, feeding studies. Despite these differences, the similarities in the design of safety studies conducted with bioengineered foods should be recognized by toxicologists. The current paper reviews the basic principles of safety assessment for bioengineered foods and compares them with the testing strategies applied to typical food ingredients. From this comparison it can be seen that the strategies used to assess the safety of bioengineered foods are at least as robust as that used to assess the safety of typical food ingredients.