Bt Cry1Ab-Modified Corn in Corn Flour—ELISA Method
Cry1Ab protein in corn is produced from a gene derived from
Bacillus thuringiensis (Bt). This method is a quantitative enzyme-linked immunosorbent assay (ELISA) test for the determination of
Bt-modified corn in corn flour. Proprietary antibodies specific for Cry1Ab protein are used.
11-30.01 Quantification of MON 810 Corn in Corn Flour by Real-Time Polymerase Chain Reaction
MON 810 corn is a genetically modified line of insect-protected corn (maize,
Zea mays) sold commercially by Monsanto as YieldGard. The protection is con-ferred by the protein Cry1Ab, a delta endotoxin produced from a gene derived from the soil bacterium
Bacillus thuringiensis (Bt). This method quantifies the relative amount of MON 810 DNA in corn flour. It makes a relative quantitation of a specific part from the taxon-specific maize gene (i.e., the high mobility group [HMG] protein gene) (Ref. 5) and of the single-copy DNA integration-border region of the genomic sequence and the inserted sequence element. This element originates from the CaMV (35S promoter) and is the result of
in vitro recombination. Real-time polymerase chain reaction (PCR) in a TaqMan assay is used (Ref. 3). The method is calibrated to estimate the copy number percent of modified corn in corn flour by using a reference material certified for its MON 810 mass fraction (Ref. 2). Copy number percents are estimated on the basis of the DNA extracted from the reference material and an assumed average genome size. The method is suitable for enforcement purposes with respect to its true-ness and interlaboratory variability (Ref. 1). It is annexed to standard ISO 21570:2005 (Ref. 4).
11-50.01 Guideline for Disclosure of Bioengineered Products
As analytical methods continue to become more sensitive, the drive to test to zero is becoming a major issue in supply chains. Thresholds for identity preservation, which are not necessarily based on safety and risk, vary depending on the property being defined. While certain interests have been promoting low thresholds for identity preservation, especially for genetically modified organisms (GMOs), these thresholds provide no useful dietary or safety information for the consumer. Their labels are based on testing, whereas those in industry prefer standards to be based on verified processes and use testing to verify processes, rather than using testing as the primary tool.
Given the pressures on the food system to nourish a growing world population in the face of climate change and increased expectations, it is neither economical nor sustainable that materials at different and ever lower thresholds be produced. Several entities, such as ingredient providers, have expressed that they are being asked to provide materials that exclude genetically engineered (GE) components. These materials are increasingly difficult to produce and offer no scientifically proven safety benefit to the consumer. Continued development in this direction has the potential to proliferate to multiple types of “non-GE” or “non-GM” products in the marketplace and to fragment efficient supply chains and agricultural production in both developed and developing nations.
The AACCI Molecular Biomarkers Committee therefore developed a guideline for disclosure of GE identity-preserved products and specifically for thresholds for voluntary labeling of products that contain GE-derived components below certain thresholds.
The guideline is aimed at providing consistent practices in food supply chains. It starts with process and is consistent with organic thresholds. The use of GE technologies is not allowed in organic production, but up to 5% adventitious presence of GE materials is permitted. It addition, the guideline is consistent with the international varietal seed standards of the Organisation for Economic Co-operation and Development. As such, it provides consistency from farm to fork.
Under the guideline, a product containing less than 5% GE content may be labeled as such. The guideline does not support the multiple thresholds that have been proposed, such as “less than 0.9% GE content,” or “as low as 0.1–0.3% GE content.” Finally, the guideline recommends that products shall not be labeled or described as “zero,” “not present,” or “free from” GE content, because the realities of crop and food and feed production preclude zero tolerance, and that products that consist primarily of materials not commercially available as GE should not be described as “non-GE” (or “non-GM”), because such labeling might be considered misbranding and misleading to the consumer.
AACCI is providing this guideline to help those in the supply chain standardize the disclosure of GE content in food. It provides a way to avoid proliferation of multiple and confusing labels that convey no nutritional or safety information to the consumer and that fragment and increase the cost of providing sufficient nutritious food for our growing population