VII. Guidance to Industry for Foods Derived From New Plant Varieties
A. IntroductionThis guidance section describes many of the scientific considerations for evaluating the safety and nutritional aspects of food from new plant varieties derived by traditional methods (such as hybridization or mutagenesis), tissue culture methods (such as somaclonal variation and protoplast fusion), and recombinant DNA methods. Although some of the safety considerations are specific to individual technologies, many safety considerations are similar regardless of the technology used. This guidance section does not attempt to delineate acceptable practices for each specific technology. FDA expects plant breeders to adhere to currently accepted scientific standards of practice within each technology. This guidance section is based on existing practices followed by the traditional plant breeders to assess the safety and nutritional value of new plant varieties and is not intended to alter these long-established practices, or to create new regulatory obligations for them.
This guidance section describes food safety and nutritional concerns, rather than performance characteristics for which the new plant varieties may have been developed. However, this guidance section cannot identify all safety and nutritional questions that could arise in a given situation and, while comprehensive, should not be viewed as exhaustive. In some cases, additional factors may need to be considered, while in other situations, some of the factors may not apply. Therefore, this guidance section also describes situations in which producers should consult with FDA on scientific issues, the design of appropriate test protocols, requirements for labeling, and whether a food additive petition may be required.
Genetic modifications of plants can have unintended or unexpected effects on the phenotype of the plant, such as poor growth or reduced tolerance to conditions of environmental stress, that are readily apparent and can be effectively managed by appropriate selection procedures. However, effects such as an alteration in the concentration of important nutrients, increases in the level of natural toxicants, or the transfer of allergens from one species to another may not be readily detected without specific test procedures. FDA believes that a scientific basis should exist to establish that new plant varieties do not exhibit unacceptable effects with respect to toxicants, nutritional value, or allergens. In cases where the host plant has little or no history of safe use, the assessment of new plant varieties should include evidence that unknown toxicants are not present in the new plant variety at levels that would be injurious to health.
In addition, by using recombinant DNA techniques, plant breeders are now capable theoretically of introducing essentially any trait (and thus substance) whose molecular genetic identity is known into virtually any plant due to the increased power and precision of recombinant DNA techniques. This guidance section, however, discusses only proteins, carbohydrates, and fats and oils, in the belief that these are the principal substances that are currently being intentionally modified or introduced into new plant varieties. Using the new techniques, it is possible to introduce a gene that encodes a protein that differs significantly in structure or function, or to modify a carbohydrate, or fat or oil, such that it differs significantly in composition from such substances currently found in food. FDA believes that plant breeders must carefully evaluate the potential for adverse effects that could result from the presence of these substances in new plant varieties.
Theoretically, genetic modifications have the potential to activate cryptic pathways synthesizing unknown or unexpected toxicants, or to increase expression from active pathways that ordinarily produce low or undetectable levels of toxicants. However, this potential has been effectively managed in the past by sound agricultural practices. The agency believes that the use of host plants with a history of safe use, coupled with a continuation of sound agricultural practice, will minimize the potential for adverse public health consequences that may arise from increased levels of unknown or unexpected toxicants.
This guidance section provides a basis for determining whether new plant varieties are as safe and nutritious as their parental varieties. The assessment scheme focuses on characteristics of the new plant variety, based on characteristics of the host and donor species, the nature of the genetic change, the identity and function of newly introduced substances, and unexpected or unintended effects that accompany the genetic change. The assessment focuses on the following considerations:
1. Toxicants known to be characteristic of the host and donor species;
2. The potential that food allergens will be transferred from one food source to another;
3. The concentration and bioavailability of important nutrients for which a food crop is ordinarily consumed;
4. The safety and nutritional value of newly introduced proteins; and
5. The identity, composition and nutritional value of modified carbohydrates, or fats and oils.
The scientific concepts described in this guidance section are consistent with the concepts of substantial equivalence of new foods discussed in a document under development by the Group of National Experts on Safety in Biotechnology of the Organization for Economic Cooperation and Development (OECD). This guidance section is also consistent with the principles for food safety assessment discussed in the Report of a Joint Food and Agriculture Organization/World Health Organization Consultation (Ref. 6).
B. Flow ChartsThe flow charts presented in sections VII.D. through VII.F. (Figures 2 through 6) outline a series of questions related to the safety and nutritional value of foods derived from the new plant variety, and are intended to provide general guidance to breeders and developers. FDA intends that these flow charts be used in conjunction with other information and practices that breeders and developers rely on to develop new plant varieties. These reflect the current state of scientific information and are not intended as regulatory requirements. As new information is developed, FDA anticipates that the flow charts may require modification.
The summary flow chart (Figure 1) presented in this section is a synopsis of FDA's safety assessment process. It describes, in a general way, the assessment for unexpected or unintended effects that may arise as a result of the specific characteristics that are associated with the host plant and donor(s), as well as the assessment of the expected or intended effects. Because Figure 1 is a summary, it should not be relied upon for a safety assessment. The boxes labeled Figure 2, Figure 3, Figure 4, and Figures 5 and 6, respectively, refer to more specific flow charts that describe, in appropriate detail, the safety assessment from the perspective of the host, donor, and new substances that are introduced into the new plant variety.
Sections VII.D. through VII.F. address the scientific considerations pertaining to the host plant, donor(s), and new substances in more detail. Each section describes information that relates to the safety assessment, presents a flow chart that summarizes the safety assessment, discusses each of the questions in that flow chart, and describes the endpoints that are reached in that flow chart.
There are three endpoints in the flow charts in this notice: (1) No concerns, (2) new variety not acceptable, and (3) consult FDA. The notes to each individual flow chart discuss the interpretation of these endpoints in relation to that particular flow chart. In general, the interpretation of "no concerns" or "new variety not acceptable" is similar for each flow chart. The endpoint "consult FDA" means that producers may need to consult FDA on regulatory questions, such as whether a food additive petition or special labeling is needed, or on technical questions, such as appropriate testing protocols or specific scientific issues.
>>>> See the accompanying hardcopy volume for non-machine-readable data that appears at this point. (Figure 1. Safety Assessment of New Varieties: Summary) <<<<
C. Effects of ProcessingProcessing (e.g., cooking) may affect the safety of a substance. This is particularly important in the safety assessment of proteins transferred from one food source to another. For example, lectins, which are inactivated by cooking, would raise a safety concern if transferred from kidney beans, which are eaten cooked, to tomatoes, which may be eaten raw. The effects of any potential differences in food processing between the donor and the new plant variety should be carefully considered at each stage in the safety assessment.
D. The Host PlantA premise basic to this guidance section is that a long history of safe use of the host species in food provides much information regarding the potential of new plant varieties to produce toxicants and antinutrients (substances that adversely affect the nutritional quality of food). In assessing the potential of the host plant to contribute unexpected harmful substances, producers should consider attributes of the host plant and its progenitors such as the following:
1. Taxonomy.
a. Variety name.
b. Known phenotypes and relevant genotypes.
2. Other species or varieties that have previously contributed genetic information to the host.
3. History of safe use.
a. Extent of previous experience.
b. The part of the plant used as food.
c. The presence and identity of potentially harmful constituents such as toxicants and antinutrients.
d. Typical methods of processing and the impact of this processing on the reduction or enhancement of effects from potentially harmful constituents.
4. The identity and level of nutrients for which the food is consumed.
Figure 2
The numbers above each box in the flow chart refer to accompanying notes that immediately follow the flow chart.
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Notes to Figure 2
1-Does the host species have a history of safe use? This guidance section is primarily designed for the development of new varieties of currently consumed food plants whose safety has been established by a history of use. If exotic species are used as hosts, testing may be needed to assure the safety and wholesomeness of the food.
2-Do characteristics of the host species, related species, or progenitor lines warrant analytical or toxicological tests?
It is not possible to establish a complete list of all toxicants that should be considered for each plant species. In general, the toxicants that are of highest concern in any particular species are those that have been documented to cause harm in normal or animal diets, or that have been found at unsafe levels in some lines or varieties of that species or related species.
In many cases, characteristic properties (such as a bitter taste associated with alkaloids) are known to accompany elevated levels of specific natural toxicants. If such characteristic provide an assurance that these toxicants have not been elevated to unsafe levels, analytical or toxicological tests may not be necessary.
3-Do test results provide evidence that toxicant levels in the new plant variety do not present a safety concern?
If a host plant or related species is known to contain toxicants whose presence must be assessed, analytical tests may be appropriate to establish that the toxicant levels are in a safe range. There is, however, a wide variation in the level of natural toxicants within and between varieties of a species, due to differences in genetic makeup and in environmental conditions during growth, harvest, and storage. Due to this natural variation, analytical tests, if necessary, should be performed using as a control the parental variety that has been grown, harvested, and stored under the same conditions as the new plant variety.
In some cases, analytical methods alone may not be available, practical, or sufficient for all toxicants whose levels are needed to be assessed. In such situations, comparative toxicological tests on the new and parental plant varieties may provide assurance that the new variety is safe. FDA encourages producers of new plant varieties to consult informally with the agency on testing protocols for whole foods when appropriate.
4-Is the concentration and bioavailability of important nutrients in the new variety within the range ordinarily seen in the host species?
If the native levels of important nutrients for which a food is widely consumed are not within the range ordinarily seen in the host species, appropriate labeling may be required. In addition, changes in bioavailability of a nutrient due to changes in form of the nutrient or the presence of increased levels of other constituents that affect absorption or metabolism of nutrients must be considered for potential nutritional impact.
5-Endpoints in Figure 2.
5a-No concerns.
When this endpoint is reached, safety and nutritional concerns relative to the host plant will generally have been satisfied.
5b-New variety not acceptable.
This endpoint is reached when test results indicate that food derived from the new plant variety may be unsafe-e.g., if it contains unacceptable levels of toxicants.
5c-Consult FDA.
Producers should consult informally with FDA when the concentration or bioavailability of important nutrients is not within the range ordinarily seen in the host species. FDA will work with the producers on a case-by-case basis to address requirements such as labeling, or other issues relating to nutritional concerns.
E. The Donor(s)
In some cases, the donor will not have a history of safe use in food. For example, the donor may be a wild species that is related to the host plant, or may be a microorganism with no history of use in food. The potential of the donor(s) to contribute undesirable characteristics to the new plant variety should be assessed. In assessing the potential of the donor to contribute unexpected harmful substances, producers should consider attributes of the donor plant, or of fragments of genetic material from one or multiple donors, to the extent that such information is available (see Figure 3).
1. Donor Plants
Attributes of the donor plant and its progenitors, such as the following, should be considered:
1. Taxonomy.
a. Variety name.
b. Known phenotypes and relevant genotypes.
2. Other species or varieties that have previously contributed genetic information to the donor plant.
3. History of use (as applicable).
a. The part of the plant used as food.
b. The presence and identity of potentially harmful constituents such as toxicants, antinutrients, and allergens.
c. Typical methods of processing and the impact of this processing on the reduction or enhancement of effects from potentially harmful constituents.
2. Fragments of Donor Genetic Material
Attributes of each donor, and its progenitors when appropriate, such as the following, should be considered:
1. Taxonomy.
2. Other species or varieties that have previously contributed genetic information to the donor(s).
3. History of use (as applicable).
a. The part of the donor(s) used as food.
b. The presence and identity of potentially harmful constituents, such as toxicants, antinutrients, and allergens.
c. Typical methods of processing and the impact of this processing on the reduction or enhancement of effects from potentially harmful constituents.
d. The association of the transferred genetic material with harmful constituents.
4. Additional information consistent with currently accepted scientific practices, such as:
a. History and derivation of molecular constructs, such as passage through microbial hosts.
b. Known activities of any introduced regulatory sequences, such as environmental, developmental and tissue-specific effects on promoter activity.
c. The presence of extraneous open reading frames, and the potential for transcription and expression of these additional open reading frames.
Figure 3
The numbers above each box in the flow chart refer to accompanying notes that immediately follow the flow chart.
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Notes to Figure 3
6-Is food from the donor commonly allergenic? If yes, can it be demonstrated that the allergenic determinant has not been transferred to the new variety of host plant? Some examples of foods that commonly cause an allergenic response are milk, eggs, fish, crustacea, molluscs, tree nuts, wheat, and legumes (particularly peanuts and soybeans). Allergens from these common sources may be knowingly or unknowingly transferred from a donor to a new variety of host plant. Knowledge of the identity of the allergenic determinant of the donor, coupled with appropriate knowledge of the genetic fragment that has been transferred from the donor to the new plant variety, may provide sufficient evidence that the allergenic determinant has not been transferred to the new variety of the host plant.
7-Do characteristics of the donor species, related species, or progenitor lines warrant analytical or toxicological tests?
It is possible that a toxicant present in the donor may be transferred to the host, e.g., during hybridization of a cultivated variety with a wild, poisonous relative. However, it is also possible to use a toxic donor safely. For example, a gene coding for an enzyme that is not toxic and does not yield toxic products may be isolated from pathogenic bacteria and safely transferred to a plant.
The potential that toxicants known to exist in the donor, related species, or progenitor lines will be present in the new plant variety should be addressed as described previously for the host plant (section VII.D.). Unless there is sufficient evidence that the toxicant has not been transferred to the new variety of host plant, such transfer should be assumed, and analytical and/or toxicological tests may be warranted. 8-Do test results provide evidence that toxicant levels in the new variety do not present a safety concern?
When the presence of donor-associated toxicants must be assessed, analytical or toxicological studies may provide assurance that the new variety is safe as described previously for the host species (section VII.D.). FDA encourages producers of new plant varieties to consult with the agency on testing protocols.
9-Endpoints in Figure 3.
9a-No concerns.
When this endpoint is reached, safety concerns relative to the donor will generally have been satisfied. 9b-New variety not acceptable.
This endpoint is reached when test results indicate that food derived from the new plant variety may be unsafe, e.g., if it contains unacceptable levels of toxicants.
9c-Consult FDA.
Appropriately designed tests may provide evidence that the suspected allergen in the donor was not transferred to the new plant variety, or is not allergenic in the new variety. Producers should consult informally with FDA on protocols that are designed to assess allergenicity. FDA will work with the producer on a case-by-case basis to address requirements such as labeling.
F. Substances Introduced Into the Host Plant From the Donor(s) Safety assessment should address the specific risks associated with the new substances introduced from the donor(s) to a degree that is consistent with currently accepted scientific practices.
1. Proteins
Depending upon the circumstances, safety assessment of an introduced protein should be based on:
1. Presence and level in the food product.
2. Origin.
3. Known or suspected allergenicity.
4. Evidence of consumption in other foods at similar levels and under similar conditions of processing (e.g., eaten cooked or uncooked).
5. Effects of processing (e.g., cooking).
6. Biological function.
7. Known or potential toxicity.
8. Chemical differences and similarities to edible proteins.
9. The presence of host-specific posttranslational modifications.
Figure 4
The numbers above each box in the flow chart refer to accompanying notes that immediately follow the flow chart.
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Notes to Figure 4
10-Is the newly introduced protein present in food derived from the plant?
For example, an enzyme introduced to alter the fatty acid composition of an oil may be removed from the oil as a result of processing. Alternatively, an enzyme introduced to confer antibiotic resistance for use as a selectable marker may be present in food products.
11-If an introduced protein is derived from a food source, the question of allergenicity must be addressed in the same fashion as was discussed from the perspective of the donor as a whole.
12-Is the introduced protein that is derived from a food source, or is substantially similar to an edible protein, reported to be toxic?
For example, some lectins are toxic unless inactivated by cooking. If a protein whose safety is dependent on processing such as cooking has been transferred from a species that is commonly cooked before consumption to a species that may be eaten raw, safety questions may arise.
13-If the intake of an introduced protein that is derived from a food source, or that is substantially similar to an edible protein, is not generally comparable to the intake of the same or similar protein in the donor or other food, the biological function of the protein should be assessed.
14-The biological function of the introduced protein should be assessed if either of the following occur:
a. The introduced protein is not derived from a food source, or is not substantially similar to an edible protein;{6}
³{6} The issue of potential allergenicity of any new protein
³(as opposed to the allergenicity of a protein derived
³from a known source of allergens) is frequently raised.
³FDA recognizes that routine procedures for testing foods
³derived from new plant varieties for the presence of
³unknown allergens are not currently available. If the
³donor has no history of use in food, the issue of allergenicity
³cannot be addressed at this time. Comparison of gene
³sequences to data banks of known allergens may become
³increasingly useful as the information on such proteins
³expands. FDA invites comments on methods that may be
³available to address the issue of allergenicity of new
³proteins in foods.
b. The intake of the introduced protein in the new variety is not comparable to the intake of the same or similar protein in the donor or other food.
15-Does the biological function of the introduced protein raise any safety concerns, or is the introduced protein reported to be toxic?
In general, proteins that function as enzymes do not raise concern{7} Exceptions include enzymes that produce substances that are not ordinarily digested and metabolized by vertebrates, or that produce toxic substances (e.g., the enzymes that convert cyanogenic glycosides to cyanide).
³{7} Pariza and Foster (Ref. 7) note that very few toxic
³agents have enzymatic properties. Exceptions include
³diphtheria toxin and certain enzymes in the venom of
³poisonous snakes.
Other functions that could raise concern include any reported toxicity, such as known toxic activity toward vertebrates, known toxic activity toward nonvertebrates when the absence of toxic activity to vertebrates is not established, and unusual properties that indicate that the protein is significantly different from other proteins found in the diet. If the function of the protein is not known, see note 17d.
16-Is the introduced protein likely to be a macroconstituent in the human or animal diet?
From a nutritional standpoint, the amount and quality of total protein in the diet, rather than of any particular protein, is of greatest significance. However, while most individual proteins (e.g., enzymes) that might be introduced into food derived from plants will be present at relatively low concentrations, some proteins (e.g., seed storage proteins){8} may become macroconstituents of the plant-derived food. Other proteins (e.g., enzymes used as selectable marker genes) may be introduced into many plants and therefore be consumed at a substantial level. Dietary exposure to such proteins should be considered.
³{8} The nutritional content of seed storage proteins
³from some crops is particularly important in the case
³of animal feed, where one crop may furnish a substantial
³portion of the diet.
17-Endpoints in Figure 4.
17a-No concerns.
When this endpoint is reached, safety concerns relative to intentionally introduced proteins will generally have been satisfied.
17b-Consult FDA: Allergens. Producers should consult informally with FDA on protocols that are designed to assess allergenicity. FDA will work with the producer on a case-by-case basis to address requirements such as labeling.
17c-Consult FDA: Toxicity. Producers should consult informally with FDA when a protein is reported to be toxic or when the safety of an introduced protein is dependent on processing such as cooking. FDA will determine on a case-by-case basis whether it will review the food additive status of these proteins, or whether the proteins are unacceptable in the new plant variety.
17d-Consult FDA: Function and toxicity. Producers should consult informally with FDA on scientific issues and design of appropriate test protocols when the function of the protein raises concern or is not known, or the protein is reported to be toxic. FDA will determine on a case-by-case basis whether it will review the food additive status of these proteins.
17e-Consult FDA: Macroconstituents in the diet. Producers should consult informally with FDA when a protein is expected to become a macroconstituent of the diet, whether as a result of its presence in high levels in one food or as a result of its use in many foods. FDA will determine on a case- by-case basis whether it will review the food additive status of these proteins.
2. Carbohydrates
Safety assessment of a new or modified carbohydrate should be based on the nature of the carbohydrate or modification.
Figure 5
The numbers above each box in the flow chart refer to accompanying notes that immediately follow the flow chart.
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Notes to Figure 5
18-Have any structural features or functional groups been introduced into the carbohydrate that do not normally occur in food carbohydrates?
For example, developments that affect carbohydrates will frequently be modifications of food starches, presumably affecting the content of amylose and amylopectin, as well as the branching of amylopectin. Such modified starches are likely to be functionally and physiologically equivalent to starches commonly found in food and thus would not suggest any specific safety concerns. However, if functional groups or structural features that normally do not occur in food carbohydrates are introduced, such modifications should be evaluated with respect to any safety concerns that may arise.
19-Have there been any alterations that could affect digestibility or nutritional qualities in a carbohydrate that is likely to be a macroconstituent in the diet?
If a vegetable or a fruit is modified to produce high levels of an indigestible carbohydrate that normally occurs at very low levels, or to convert a normally digestible carbohydrate to an indigestible form, nutritional questions may arise.
20-Endpoints in Figure 5.
20a-No concerns.
When this endpoint is reached, safety and nutritional concerns relative to intentional modifications of food carbohydrates will generally have been satisfied. 20b-Consult FDA.
Producers may consult informally with FDA on scientific issues.
FDA will determine on a case-by-case basis whether it will review the food additive status of these carbohydrates, and will work with the sponsor on a case-by-case basis to address requirements such as labeling.
3. Fats and Oils Safety assessment of a new or modified fat or oil should be based on its composition and the presence of any unusual components at levels that would cause safety concern.
Figure 6
The numbers above each box in the flow chart refer to accompanying notes that immediately follow the flow chart.
>>>> See the accompanying hardcopy volume for non-machine-readable flow chart that appears at this point. <<<<
Notes to Figure 6
21-Has there been an intentional alteration in the identity, structure, or composition of fats or oils that are likely to be a macroconstituent in the diet?
Some alterations in the composition or structure of fats and oils, such as an alteration in the ratio of saturated to unsaturated fatty acids, may have significant nutritional consequences, or result in marked changes in digestibility. Other changes may produce a fat or oil that has been altered such that it is no longer representative of fats and oils from the host species.
22-Are any unusual or toxic fatty acids produced in the new variety?
For example, safety questions may arise as a result of the presence of fatty acids with chain length greater than C-22, fatty acids with cyclic substituents, fatty acids with functional groups not normally present in dietary fats and oils, and fatty acids of known toxicity (e.g., erucic acid).
23-Endpoints in Figure 6.,br/> 23a-No concerns. When this endpoint is reached, safety and nutritional concerns relative to intentional modifications of fats and oils will generally have been satisfied.
23b-Consult FDA. Producers may consult informally with FDA on scientific issues.
FDA will determine on a case-by-case basis whether it will review the food additive status of these fats or oils, and will work with the sponsor on a case-by-case basis to address requirements such as labeling.
G. Toxicology Feeding studies or other toxicological tests may be warranted when the characteristics of the plant or the nature of the modification raise safety concerns that cannot be resolved by analytical methods. FDA recognizes that feeding studies on whole foods have limited sensitivity because of the inability to administer exaggerated doses. Because of the difficulty of designing meaningful studies, FDA encourages companies to consult informally with the agency about test protocols.
H. Other Information The information described below is not directly addressed in the flow charts but should be considered during the development of new plant varieties.
1. Nucleic Acids
Introduced nucleic acids, in and of themselves, do not raise safety concerns. Thus, for example, the introduction of a gene encoding an anti-sense ribonucleic acid (RNA) would not raise concerns about either the gene or the anti-sense RNA. Any safety considerations would focus on the intended effects of the anti- sense RNA. Hence, continuing the example, if the anti-sense RNA were used to suppress an enzyme, then just as for any other method intended to suppress an enzyme, such as deletion or nonsense mutations, the metabolic effects on the host plant of such enzyme suppression should be considered at the conceptual stage of development and monitored, when appropriate and feasible.
2. Metabolic Considerations
The effects of an intentional alteration of a biochemical pathway should be considered at the conceptual stage of development, and monitored when appropriate and feasible. For example, are there any toxic effects of a metabolic imbalance with respect to enzyme substrate depletion and product accumulation? Are any auxiliary pathways likely to be affected?
3. Stability
The genetic stability of the new plant variety and the inheritance of the introduced genetic material as a single Mendelian trait are important safety considerations. A safety assessment of food derived from early generations of the new variety may not be valid if the new genetic material is expressed at substantially different levels in subsequent generations. Factors that favor stability include a minimum number of copies of the introduced genetic material, and insertion at a single site.
I. Future Workshop on Scientific Issues
FDA recognizes the desirability of establishing consensus within the industry, the scientific community, and the public on the agency's scientific assessment approach to food safety presented in this guidance section. For this reason, FDA plans to announce, in a future Federal Register notice, a workshop to discuss specific scientific issues. The notice announcing the workshop will include a description of the scientific issues to be discussed. FDA invites comment on topics that might be addressed at such a workshop.