Novel Food Information: Sugarcane CTC91087-6
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Background:
Health Canada has notified Centro de Tecnologia Canavieira that it has no objection to the food use of raw and refined sugar derived from sugarcane event CTC91087-6. The Department conducted a comprehensive assessment of this variety according to its Guidelines for the Safety Assessment of Novel Foods. These Guidelines are based upon internationally accepted principles for establishing the safety of foods with novel traits.
The following provides a summary of the notification from Centro de Tecnologia Canavieira and the evaluation by Heath Canada and contains no confidential business information.
1. Introduction
Centro de Tecnologia Canavieira developed sugarcane CTC91087-6 to be insect-resistant to help control sugarcane borer infestations. Recombinant DNA techniques were used in order to make the sugarcane insect-resistant. The sugarcane is to be cultivated only in Brazil and the sugarcane-derived food ingredients to be imported into Canada are raw and refined sugars.
The safety assessment performed by Food Directorate evaluators was conducted according to Health Canada's Guidelines for the Safety Assessment of Novel Foods. These Guidelines are based on harmonization efforts with other regulatory authorities and reflect international guidance documents in this area (e.g., Codex Alimentarius). The assessment considered: how sugarcane CTC91087-6 was developed; how the composition and nutritional quality of raw and refined sugars derived from sugarcane CTC91087-6 compared to non-modified varieties; and the potential for sugarcane CTC91087-6 to be toxic or cause allergic reactions. Centro de Tecnologia Canavieira provided data that demonstrates that raw and refined sugar derived from sugarcane CTC91087-6 is as safe and of the same nutritional quality as traditional sugarcane varieties used as food in Canada.
The Food Directorate has a legislated responsibility for pre-market assessment of novel foods and novel food ingredients as detailed in the Food and Drug Regulations (Division B.28). Food use of sugarcane CTC91087-6 is considered a novel food under the following part of the definition of novel foods:
"c) a food that is derived from a plant, animal or microorganism that has been genetically modified such that:
- the plant, animal or microorganism exhibits characteristics that were not previously observed in that plant, animal or microorganism."
2. Development of the Modified Plant
The petitioner has provided information describing the methods used to develop sugarcane CTC91087-6 and data that characterize the genetic modification that results in the insect-resistance through the expression of the Cry1Ac cassette. Sugarcane CTC91087-6 was produced though Agrobacterium mediated transformation of embryogenic sugarcane cells of the CTC9001 variety with the transformation plasmid pCTC524. The transgene for Cry1Ac is a synthetic sequence from Bacillus thuringiensis, a ubiquitous soil bacterium, which has been optimized for sugarcane expression and truncated. The first expression cassette contains the Cry1Ac coding sequence under the regulation of the maize Ubi-1 promoter and intron, and the NOS 3' polyadenylation signal. The second cassette contains the pat coding sequence under the regulation of the Ubi-1 promoter and intron, and the NOS 3' polyadenylation signal.
3. Characterization of the Modified Plant
Southern blot, PCR and DNA sequence analysis was performed in order to characterize the number of insertion sites and copies of the integrated T-DNA as well as the presence or absence of plasmid backbone sequence. This analysis demonstrated a single copy of the transgene at a single locus in sugarcane CTC91087-6. The analysis detected no vector backbone sequences present in sugarcane CTC91087-6.
Commercial sugarcane relies upon vegetative (clonal) propagation and therefore it would be expected that stability of the inserted T-DNA is maintained over many generations. Southern blot analysis of leaves from multiple vegetative propagations was performed and the results demonstrated the insert stability.
4. Product Information
Two new proteins are expressed in sugarcane CTC91087-6 based on the characterization of the inserted genetic material. The Cry1Ac and PAT proteins produced by the insertion of the two cassettes were characterized. The Cry1Ac and PAT proteins expressed in this sugarcane line were of the expected molecular weight via construct sequence analysis and Western blot analysis. The same analysis of molecular weight was confirmed with E.coli produced Cry1Ac using the same transformation construct used to generate CTC91087-6 sugarcane. A MALDI-TOF analysis of the plant-expressed Cry1Ac protein amino acid sequence had a predicted high coverage of 87%, and there was no glycosylation of either Cry1Ac and PAT proteins in the plant.
The petitioner has provided information such as Western blot, MALDI-TOF, and glycosylation analyses to support the equivalency of the plant expressed Cry1Ac and PAT proteins in CTC91087-6 sugarcane to the previously assessed proteins found in maize DBT418 (Cry1Ac, PAT), maize BT176 (PAT), and the Intacta soybeans which are a cross of the two approved lines MON87701 (Cry1Ac) and MON 89788 (glyphosate tolerant).
5. Dietary Exposure
The genetic modification of sugarcane CTC91087-6 is not intended to alter any of its nutritional aspects when compared to conventional non-genetically modified varieties. It is expected that refined sugar from sugarcane CTC91087-6 will be used in applications similar to refined sugar from conventional sugarcane varieties and thus no change in the food use of refined sugar is anticipated.
6. Nutrition
The sugarcane-derived food ingredients imported into Canada from Brazil are raw sugar (~95%) and refined sugar (~5%). Upon importation, all raw sugar is required to be refined before use as a human food or food ingredient, so the food or food ingredient consumed by Canadians that would be derived from sugarcane event CTC91087-6 is refined sugar. Nutritional composition analysis of refined sugar is not informative as it is almost entirely composed of sucrose (99.93%), the remaining impurities being water, inverted or reducing sugar (glucose and fructose), ash, coloured components, and other organic non-sugar compounds. Canadians do consume a small amount of sugarcane stalk as a confection or food ingredient in Asian cuisine, but sugarcane is not a significant source of other nutrients and sugarcane generally has low digestibility due to its high fibre content.
The compositional parameters chosen for nutrient analysis were based on the recommendations of the Organization for Economic Co-Operation and Development (OECD) "Consensus Document on Compositional Considerations for New Varieties of Sugarcane (Saccharum ssp. hybrids): Key Food and Feed Nutrients, Anti-nutrients and Toxicants" (2011). Specifically, the petitioner measured the levels of proximates (i.e. moisture, protein, total fat, ash, crude fibre) and sucrose, glucose, and fructose. In addition, the petitioner measured Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF) compositions due to relevance to the transformed events.
Data from five field trials over the 2017 to 2018 growing season in sugarcane growing areas of Brazil was analyzed. The field trials utilized a randomized block design with four replicates per block. Each block contained the test cultivar (CTC91087-6), the control cultivar (isoline CTC9001), and four of six reference varieties (CTC20, CTC4, RB867515, RB855156, CTC9002, and RB965902) grown under identical conditions.
No statistically significant differences were observed in analytical results between CTC91087-6 and the control or the reference varieties. As well, all average nutrient levels for all varieties were within the ranges of the literature values set out in the OECD (2011). The minimum and/or maximum of protein, fat, and crude fibre were outside the OECD ranges; however, these values were not significantly different than the control variety.
Based on the information provided on the composition of CTC91087-6, control CTC9001 and other reference varieties, there aren't any nutritional safety concerns with the sale of foods derived from CTC91087-6 sugarcane.
7. Chemistry/Toxicology
Dietary exposure to the Cry1Ac and PAT proteins derived from sugarcane CTC91087-6 is limited to refined sugar. Refined sugar is a highly processed product that is subjected to high temperatures and fluctuating pH values resulting in the progressive degradation of sugarcane protein. Levels of the Cry1Ac and PAT proteins in raw sugar derived from sugarcane CTC91087-6 were below the level of detection (i.e., LOD 0.0085 µg/g sugar and 0.006 µg/g sugar respectively), and therefore exposure to the novel proteins is expected to be negligible.
As raw sugar is further processed and purified to refined sugar (>99.8%), any residual protein is expected to be further degraded during processing. Therefore, exposure to the Cry1Ac and the PAT proteins expressed in sugarcane CTC91087-6 by consuming the highly processed refined sugar is expected to be negligible.
The equivalency of the Cry1Ac and PAT (bar) proteins expressed in sugarcane CTC91087-6 to previously assessed Cry1Ac and PAT (bar) proteins in crops that have been evaluated by Health Canada and authorized for food use was demonstrated.
Based on the data provided by the petitioner, exposure to the Cry1Ac and PAT proteins in refined sugar is expected to be negligible. Nevertheless, previous safety assessments have demonstrated Cry1Ac and PAT proteins are not homologous with any known allergens and experimental data suggests that both proteins are rapidly digested in simulated gastric fluid and not available for exposure as allergens.
Based on the data provided, the negligible exposure to the Cry1Ac and PAT proteins, and the history of safe food use of the Cry1Ac and PAT proteins in other approved crops, consumption of refined sugar derived from sugarcane CTC91087-6 did not raise any toxicological concerns and is not expected to present an allergenic concern.
Conclusion:
Health Canada's review of the information presented in support of the food use of raw and refined sugar derived from sugarcane CTC91087-6 does not raise concerns related to food safety. Health Canada is of the opinion that food derived from sugarcane CTC91087-6 is as safe and nutritious as food from current commercial sugarcane varieties.
Health Canada's opinion deals only with the food use of sugarcane CTC91087-6. Issues related to its environmental release and use as animal feed have been addressed separately through existing regulatory processes in the CFIA.
This Novel Food Information document has been prepared to summarize the opinion regarding the subject product provided by the Food Directorate, Health Products and Food Branch, Health Canada. This opinion is based upon the comprehensive review of information submitted by the petitioner according to the Guidelines for the Safety Assessment of Novel Foods.
(Également disponible en français)
For further information, please contact:
Novel Foods Section
Food Directorate
Health Products and Food Branch
Health Canada, PL2204A1
251 Frederick Banting Driveway
Ottawa, Ontario K1A 0K9
hc.bmh-bdm.sc@canada.ca
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