August 16, 2002
Article published by the
Journal of the American College
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
Substantial Equivalence guides the
identification of differences between a new variety and its
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
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
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