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Food Safety Assessment. Kevin Greenlees, PhD, DABT Kathleen Jones, PhD. What are the risks of direct or indirect adverse outcomes associated with the consumption of the GE animal as food or feed?. What are the direct and indirect risks posed to the GE animal?
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Food Safety Assessment Kevin Greenlees, PhD, DABT Kathleen Jones, PhD
What are the risks of direct or indirect adverse outcomes associated with the consumption of the GE animal as food or feed? What are the direct and indirect risks posed to the GE animal? (e.g., can surveying the health and other phenotypic characteristics of the animal inform us with respect to risk to the animal and potential human food safety concerns?) Are the genotype or phenotype changing over the product lifespan in a way that would affect the risks associated with the product? Is there a plan in place to monitor those changes? Does the insertion of the rDNA construct pose a hazard to the animal, humans, other animals by feed, or the environment? Are there sequences that are likely to contain potential hazards to the animal, humans, or animals consuming food from that animal, or the environment? e.g., does the construct contain mobilizable sequences from viruses that may be endemic in that species? Describes the animal, construct, and proposed claim Food/Feed Safety What hazards/risks have been identified in the hierarchical review?
Established Food Safety Standard The food safety standard is reasonable certainty of no harm – NOT absolute safety
Whole Foods Toxicological testing of whole foods in animal models is challenging • Complex mixtures • Wide variation in composition • Impact on dietary balance • High dose testing not possible
Approach Identify and characterize hazards • Direct effects • Indirect effects Analytical methods
Direct v IndirectIntended v Unintended Direct Adverse Effect (Food Safety) adverse outcome resulting from human consumption of edible products from the rDNA animal coming into contact with the construct or its gene product(s) Indirect Adverse Effect (Food Safety) adverse outcome resulting from human consumption of edible products from the rDNA animal that contain hazards due to the construct or gene product perturbing the food animal’s physiology Intended effects changes in the rDNA animal brought about deliberately by introduction of the rDNA construct and its predicted gene product(s). These may or may not pose direct or indirect effects on food safety. Unintended effects changes in the rDNA animal resulting from the interaction of the rDNA construct or its gene product(s) with the physiology of the animal such that its metabolism is altered. These may or may not pose direct or indirect effects on food safety.
Direct Effects • Result from the expression product(s) of the inserted construct directly producing harm • Toxicological testing on case-by-case basis • Allergic assessment of proteins new to food
Indirect Effects • Effects other than direct impact of the expression product in food. • Nutritional deficiency identified in compositional analysis
Conceptual Overview of Food Safety Evaluation Construct Gene Product Direct Effects Indirect Effects Direct Effects Indirect Effects Metabolic Δ such that consumption of edible tissue may pose risk (altered levels of expected nutrients, inherent metabolites or sequestered xenobiotics) Consumption of edible product containing GP causes toxicity (allergenicity, GI disturbance, other tox) Insertional Mutagenesis in structural or regulatory region None (DNA is GRAS)
Conceptual Overview of Food Safety Evaluation • The previous slide is a graphical summary of how one may approach the evaluation of food safety of edible products from GE animals. It indicates a GE animal, the construct that goes into it, and the resulting gene expression products. It subsequently indicates direct and indirect effects that may occur as the result of the construct or the expression products. The construct is not expected to cause direct effects as the agency has previously determined that DNA is generally recognized as safe (GRAS). Indirect effects caused by the construct could result from insertional mutagenesis in either structural or regulatory regions of the genome. • The gene product can cause direct effects via the consumption of edible products, products containing gene products that cause toxicity (allergenicity, gastrointestinal disturbance, or other toxicity). Indirect toxicity can result from metabolic changes such that consumption of edible tissue that may pose risk, for example, altered levels of expected nutrients, inherent metabolites or sequestered xenobiotics).
Analytical Methods for GE Animal • For a tolerance • For identity
Analytical Method for a Tolerance • Only in food producing animals • Only if a tolerance is needed • Demonstrates marker analyte present at or below tolerance in target tissue
Analytical Method for Identity: Characteristics • Identifies approved GE animal in mixed population • Determines edible tissue is from approved GE animal • Discriminates approved product from “knock-off” • Practical in a regulatory laboratory • May provide useful information if durability failure
Information Reviewed Sponsor affirmation Animal identification; facilities; containment procedures Animal and product disposition methods and records “Regulatory Method” procedures for transgene identification for animals and edible tissues Conclusions Plan likely to ensure that GE animals will not enter the food or feed supply Regulatory method adequate to identify animals/meat No food/feed from this lineage of GE animals will enter food/feed supply Food/Feed Safety of