ARCHIVED - Novel Food Information

TUSC1 Corn

Health Canada has notified Pioneer Hi-Bred International that it has no objection to the food use of TUSC1 corn. 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 Pioneer Hi-Bred International and the evaluation by Heath Canada and contains no confidential business information.

1. Introduction

TUSC1 corn was developed by selecting from a population of corn fixed for mutations caused by a naturally occurring process, Mu transposon insertion. Mu transposons are naturally occurring transposable elements in corn and a variety of other grass species, which randomly insert into active genes during sexual crossing. Insertion of a Mu element into a gene causes a loss or reduction in gene expression, in this case a reduction in the expression of the 27kDa γ-zein storage protein. Zein proteins are the principal storage proteins in corn, of which the 27kDa γ-zein storage protein comprises approximately 15%. A reduction in the expression of this protein may increase the digestibility of corn potentially causing an increase in the available energy of corn grain.

The assessment conducted by Food Directorate evaluators determined how TUSC1 corn was developed; how its composition and nutritional quality compares to traditional corn; and the potential for the presence of any toxicants, anti-nutrients, or allergens. Pioneer Hi-Bred has provided data which demonstrates that TUSC1 corn is as safe and nutritious as the conventional corn varieties sold in Canada.

The Food Program has a legislated responsibility for pre-market assessment of novel foods and novel food ingredients as detailed in the Food and Drug Regulations (Division 28). Food use of TUSC1 corn 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

(ii) the plant, animal, or microorganism no longer exhibits characteristics that were previously observed in that plant, animal of microorganism."

2. Development of the Modified Plant

The TUSC1 corn line was developed by Pioneer Hi-Bred International using the Trait Utility System in Corn (TUSC). This system is described as a population of corn plants generated through traditional breeding of inbred corn lines with lines known to be active for Mu transposons. These crosses result in a population of plants that have Mu insertions throughout their genome and can be screened for desirable traits. In the TUSC population the petitioner identified one corn line containing a heritable loss of 27kDa γ-zein storage protein expression.

3. Characterization of the Modified Plant

The petitioner has provided the results of several studies confirming that the Mu insertion occurs in the 27kDa γ-zein gene and that this insertion does cause a decrease in the level of protein expression.

The stable inheritance of both the modified gene and the associated trait, reduced expression of the 27 kDa gamma zein protein, were demonstrated over multiple generations of TUSC1 plants using molecular and phenotypic analyses respectively. Chi-square statistical analyses of this data showed that the trait segregated in the offspring in the expected ratio. Additionally, the petitioner has demonstrated that TUSC1 corn is fixed for Mu insertions.

4. Product Information

Corn line TUSC1 is expected to be used in similar applications as traditional corn varieties by the food industry. The petitioner has indicated that the greatest use of yellow dent corn in food is the production of starch and sweetener products through wet milling. Dry milling is also used to produce corn grits, flour and meal, although the greatest food product from dry milling is in brewing.

5. Dietary Exposure

TUSC1 corn is expected to be used in similar applications as traditional corn varieties by the food industry.

6. Nutrition

The design and methods of all the field trial experiments used to test corn TUCS1 were acceptable. All analyses of test and control were done using approved scientific and appropriate statistical methods.

Test and control substances were grown in a randomized block design, at 4 locations in the USA and Canada. Test and control were analyzed for 45 nutrients and anti-nutrients, in grain, as follows: Proximates: crude protein, crude fat, ash, crude fibre, plus acid detergent fibre (ADF), neutral detergent fibre (NDF); Minerals: calcium, phosphorus, copper, iron, magnesium,manganese, potassium, sodium, zinc; Fatty Acids: palmitic, stearic, oleic, linoelic, linolenic acid; Amino Acids: methionine, cysteine, lysine, tryptophan, threonine, isoleucine, histidine, valine, leucine, arginine, phenylalanine, glycine, alanine, aspartic acid, glutaminc acid, proline, serine, tyrosine; Vitamins: beta-carotene B1, B2, folic acid, E [alpha tocopherol isomer]; Anti-nutrients: phytic acid, trypsin inhibitor. 8 nutrients and anti-nutrients in forage were also analyzed.

7. Chemistry/Toxicology

TUSC1 corn does not express any substances novel to corn and maize is noted in the OECD consensus document on compositional requirements not to be a common allergenic food. Based on the information provided, Mu insertion in corn is a spontaneous event that occurs naturally in corn. The potential of this event to induce unintended effects on the corn genome would not differ in the TUSC1 corn line as compared to traditionally-bred maize. Based on this information TUSC1 corn is deemed to be as safe as the parental varieties from which it was derived and is considered to be acceptable as a food source for humans.


Health Canada's review of the information presented in support of the food use of TUSC1 corn does not raise concerns related to food safety. Health Canada is of the opinion that food derived from TUSC1 corn is as safe and nutritious as food from current commercial corn varieties.

Health Canada's opinion deals only with the food use of TUSC1 corn. Issues related to its use as animal feed have been addressed separately through existing regulatory processes in the Canadian Food Inspection Agency.

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
Tunney's Pasture
Ottawa, Ontario K1A 0L2

Telephone: (613) 941-5535
Facsimile: (613) 952-6400

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