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U.S. Department of Health and Human Services

Animal & Veterinary

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FDA Veterinarian Newsletter March/April 2000 Volume XV, No II

by Michaela G. Alewynse, Ph.D.

Adapted from a January 26 presentation made at the Association of American Feed Control Officials Midyear Meeting in Phoenix, Arizona.

The Office of Surveillance and Compliance in the Center for Veterinary Medicine (CVM) is responsible for reviewing data on genetically modified plants intended for use in animal feed. The Federal Food, Drug, and Cosmetic Act, which delineates FDA's regulatory authority for foods, defines food as articles used for food or drink for man and other animals. The Act, however, does not require pre-market clearance of food and thus, many genetically modified plants do not require formal pre-market review by the FDA as they are food.

The first modified plant evaluated by the Agency was the Calgene FlavrSavrTM tomato which has improved ripening qualities. Calgene requested FDA regulation of the inserted marker gene product, aminoglycoside 3'-phosphotransferase II, an enzyme, as a food additive due to the novelty of the technology. This enzyme is encoded for by the kanr or APHII gene. FDA actually regulates the gene product or its intended effect, not the inserted DNA itself. Thus, it is the gene product, aminoglycoside 3'-phosphotransferase, that was approved in 1994 as a food additive for food and feed usages in tomato, oilseed rape, and cotton (21 CFR 173.170 and 573.130).

In 1992 the FDA published a Statement of Policy in the Federal Register for Foods derived from New Plant Varieties. This policy applies to both genetically modified plants and those derived through other means. The 1992 policy sets out how the developers of new plant varieties should evaluate the safety and nutritional value of these foods. This science-based evaluation process is determined by the characteristics of the food, not its method of development. One primary focus is to determine if there are any unexpected effects in the new variety due to the genetic modification. These effects could include: 1) changes in toxicant or anti-nutrient levels; 2) changes in nutrient concentrations; and 3) alterations in allergenicity, i.e., the unintended movement of an allergenic protein from one food to another. The policy also addresses how the developers assess the safety of introduced proteins and other novel substances, the safety of any modified carbohydrates, fats, or oils, and also the products coded for by marker genes. The use of antibiotic resistance marker genes is also addressed in an Agency draft guidance document, which published in 1998. Plant developers can continue to use antibiotic resistance marker genes, but the guidance urges them to consider current medical practices and whether usage of the marker gene could compromise antibiotic effectiveness.

Developers are encouraged to voluntarily consult with the Agency at any time concerning a new genetic modification and may submit a summary of their evaluation of the new variety containing the modification for Agency review. These summaries are reviewed by both the Center for Food Safety and Applied Nutrition (CFSAN) and CVM to determine if the new variety differs in a significant manner from traditional crop lines. If all issues have been satisfactorily addressed, a letter is issued by CFSAN with CVM concurrence indicating that the consultation process is complete for that particular modification event. Information pertaining to the consultation process and FDA regulation of foods derived through biotechnology is available on the Foods WWW site under Biotechnology. It can also be accessed through the CVM WWW site. This table lays out the crops, modification, and numbers of varieties that have completed the voluntary consultation process.

CornHerbicide tolerant3
 Male sterile2
 Insect protected5
 Herbicide tolerant/ Insect protected2
FlaxHerbicide tolerant1
Oilseed RapeMale sterile/ Fertility restorer2
 Herbicide tolerant4
 Laurate canola1
 Phytase production1
CottonHerbicide tolerant4
 Insect protected1
 Herbicide tolerant/ Insect protected1
SoybeanHerbicide tolerant2
Sugar beetHerbicide tolerant2
Total 32

Many of these plants have been modified to be herbicide tolerant and/or pest resistant. Pest resistant varieties fall under the regulatory authority of the Environmental Protection Agency (EPA). EPA is responsible for evaluating the safety, including environmental safety, of the introduced pesticide and all necessary genetic material. Recently, EPA imposed new restrictions on the use of some pesticidal corn varieties, because of concerns about the development of insect resistance. In these plants, FDA’s authority is limited to an assessment of unintended effects due to the genetic modification, primarily alterations in nutrient and toxicant concentrations. Herbicide resistant varieties fall under the regulatory authority of FDA with the exception that EPA is responsible for evaluating the safety of any applied herbicides and any resultant residues or metabolites under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). FDA evaluates the variety itself including the safety of the expression product of the introduced genetic material.

The labeling of food derived from genetically modified plants is a matter of some controversy. FDA does not consider the method of production, including genetic modification, to be meaningful information which is required to be on product labeling unless the modification results in a significant material change in the food product. For example, a variety of canola which supplies a significant amount of phytase activity has a proposed feed ingredient definition as phytase canola to reflect the presence of the desired enzyme. However, the majority of the plants which have completed the consultation process have not triggered any labeling requirement. FDA recently held 3 public listening sessions across the United States to solicit comments on labeling, the type of FDA's review process, public disclosure of information, and other issues associated with these products. Transcripts of these sessions are available on the FDA WWW site. FDA will evaluate this information and determine if changes are needed in its policy. More information about FDA's policy concerning food obtained from genetically modified organisms is available at www.fda.gov/oc/biotech/default.htm.