Food Safety Evaluation of Crops Produced through Biotechnology

August 16, 2002

Article published by the Journal of the American College of Nutrition
Author: Bruce M. Chassy, PhD
University of Illinois, Urbana, Illinois


Agricultural biotechnology has been widely adopted in agriculture but is also the focus of controversy. Questions have arisen regarding food and environmental safety. In the US, responsibility for ensuring agricultural and environmental safety is delegated to the USDA and EPA, respectively. The FDA has primary responsibility for food safety, with the exception that the EPA has responsibility for the safety of proteins in plants associated with insect defense mechanisms. The food safety assessment, whether performed by the FDA or the EPA, requires evaluation of the safety of 1) the newly added DNA, 2) the safety of the newly introduced gene product and 3) the overall safety of the balance of the food. A paradigm called "Substantial Equivalence" guides the assessment. The principal food safety issues for new varieties crops are 1) potential toxicity of the newly introduced protein(s), 2) potential changes in allergenicity, 3) changes in nutrient composition, 4) unintended effects giving rise to allergenicity or toxicity and 5) the safety of antibiotic resistance marker-encoded proteins included with the transgene. All of these must be taken in the context of the predicted range of dietary exposures. The evaluation seeks to establish that there is a "reasonable likelihood of safety" and that new varieties are as safe as or safer than crops produced by traditional methods. Indeed, after extensive safety testing and some five years of experience with such crops in the marketplace, there is not a single report that would lead an expert food scientist to question the safety of such transgenic crops now in use.

Key teaching points:

  • The EPA, USDA and FDA have responsibility for regulating the food and environmental safety of food produced through biotechnology.

  • Substantial Equivalence guides the identification of differences between a new variety and its conventional counterpart.

  • Pre-market safety assessment evaluates the safety of the newly introduced DNA and proteins. Predicted dietary exposure is an important consideration.

  • A major focus of the assessment is to determine if any unintended and undesirable changes have occurred. Similarity of the plantís appearance, properties and composition is evidence that no significant changes have occurred.

  • The crops approved to date (50) are essentially identical to their conventional counterparts.

  • The safety assessment has concluded that there are no new or unusual risks and that the crops are as safe as their conventional counterparts.

Review in Crop Biotech Update
(A weekly summary of world developments in agri-biotech for developing countries, produced by the Global Knowledge Center on Crop Biotechnology, International Service for the Acquisition of Agri-biotech Applications SEAsiaCenter (ISAAA), and CAB International)

Dr. Bruce Chassy of the University of Illinois, states that "crops produced through biotechnology have proven to be as safe as or safer than crops produced by conventional breeding". He further elaborates that these crops could even be safer using Bt corn as an example. It needs less pesticides thus there would be less exposure to farmers, surrounding communities and non-target organisms.

Chassy's article "Food safety evaluation of crops produced through biotechnology" was published in the Journal of the American College of Nutrition, Vol. 21, No. 3 (2002). He described the evaluation process GM foods undergo before it is approved for cultivation and eventual commercialization.

The author made an analogy regarding a "wait and see" approach regarding technologies. He said that had the US waited to accumulate evidence, they would have abandoned railways because during the first couple of years, early train travel was unsafe and often lethal. He said we would also have abandoned electricity because there were many fires, injuries and deaths at first. In contrast, GM crops have been around for five years and "there is not a single report that would lead an expert food scientist to question the safety of such transgenic crops now in use". Chassy said that a major lesson is that "we should analyze and judge the safety of individual products that are the applications of a
new technology rather than the technology itself".

The article can be downloaded at 

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