Chapter 13 - Grading

Grading

The grade descriptions, definitions and tables in this chapter are taken from the Canadian Grain Commission Grain Grading Guide. As this information is subject to change, the Canadian Grain Commission accepts no responsibility for the accuracy of the information in this publication. Check the Grain Commission Web site at www.cgc.ca for current information.

Canola from Canada is recognized for its high quality that is maintained through breeding programs, seed multiplication regulations, and the Canadian grain grading system. Although canola and rapeseed are both members of the same botanical family, the designation Canola has been established and is applicable to varieties which meet the canola standard for low erucic acid and glucosinolates.

The Canada Grain Act provides for the grading of both canola and rapeseed. Canola grades are applied to varieties that meet the canola standards. Rapeseed grades apply to varieties designed for industrial use, but these are grown and delivered under special identity preserved contracts.

The grading system allows canola shipments to be segregated into grades according to quality. It assures the grower of a fair return for the product while allowing the processor access to a large quantity of seed within acceptable quality standards.

Dockage Determination

When canola is delivered to a licensed primary or terminal elevator and/or to a crushing plant, a representative sample is drawn. This sample is used for determining grade and dockage. Dockage is defined under the Canada Grain Act as any material intermixed with a parcel of grain, other than kernels of grain of a standard of quality fixed by or under this Act for a grade of that grain, that must and can be separated from the parcel of grain before that grade can be assigned to the grain. In other words, dockage in canola refers to the readily removable foreign material that is removed in the cleaning process. Dockage is removed by following set procedures as described by the Official Grain Grading Guide. Copies of this publication can be obtained from the Canadian Grain Commission from its Web site at www.cgc.ca or from its office in Winnipeg at:

Canadian Grain Commission
600-303 Main Street,
Winnipeg MB R3C 3G8
Telephone: (204) 983-2770
Fax: (204) 983-2751

The sample taken from the delivery point is referred to as the unclean or dirty sample. Its weight is the gross weight of the sample. Dockage is assessed on the gross weight of the sample. Dockage is assessed in two stages:

• normal cleaning procedures, using the Carter dockage tester
• cleaning for grade improvement–this cleaning is done at any time after normal cleaning has been completed

Commercially clean primary samples can have up to 0.5% for broken and reasonably sound canola or rapeseed deducted from the gross weight of the dockage. In not commercially clean primary samples, there is no allowance for broken and reasonably sound canola or rapeseed. All material removed by the slotted sieves is assessed as dockage.

Dockage is not reported for samples grading:

• Canola, Sample Canada Account Fireburnt
• Canola, Sample Salvage
• Canola, Sample Condemned

After normal cleaning, cleaning for grade improvement using approved equipment can be done if the grade of a delivery can be improved by additional cleaning. It is possible to improve the grade by assessing additional dockage by the removal of either excessive inseparable weed seeds or damaged canola, provided that not more than about 5.0% of the canola is removed for each single grade improvement achieved. For canola that qualifies only for Sample Canada, Account Admixture or Sample Canada, Account Damaged after cleaning for grade improvement, dockage is assessed using the appropriate equipment.

Machine Separation is defined by the Canadian Grain Regulations, and applies to cereal grains or mixtures of cereal grains in canola. It is required only at licensed terminal elevators, although it may be done at other elevators. The procedure does not apply to canola graded in eastern Canada. Machine separation must be performed on canola samples if both the following conditions apply:

• the dockage removed contains more than 6.0% of cereal grain, based on the gross weight of the sample
• the cereal grain removed qualifies for a grade other than screenings after cleaning by approved procedures

In addition:

• dockage material removed by a machine separation is added to total dockage
• machine separations are recorded by grade
• machine separations are reported to the nearest 0.1%

For example:

• 85.0% Canola, No. 1 CAN
• 9.4% Wheat, No. 1 CWRS
• 5.6% dockage

Wild oats in canola are classed as dockage, except when in admixtures with other grains that qualify for a Mixed Grain grade, otherwise, all material removed by the Machine Separation is included in the total dockage assessed.

At the end of these steps, dockage is calculated from the sum of the following:

• material that remains on the top of the round-hole sieve less any cereal grain or mixture of cereal grain, which is eligible for machine separation
• material removed as dockage from a machine separation
• material that passes through the slotted sieve
• material removed by aspiration
• material that passes over the No. 000 riddle
• inseparable material, up to established grade tolerances, handpicked from the cleaned sample
  • In Canola, Rejected (grade) Account Stones, dockage includes inseparable material handpicked from the cleaned sample up to the tolerance for the grade of the sample.
  • In Sample grades, inseparable material is not included as dockage. When the weight of the inseparable admixture exceeds 2.0% of the net weight, the admixture becomes a second reason for the sample grade. This is recorded in Remarks.
• soft earth pellets handpicked from the cleaned sample
• material removed by cleaning for grade improvement

The sample after cleaning and removal of dockage is referred to as the cleaned sample. Its weight is the net weight of the sample. Percentages by weight for grading refer to percentages of the cleaned sample, or the net weight.

Canola Grading

After dockage has been removed and determined, the cleaned sample is graded on the basis of a visual assessment of grading factors and a mechanical application of established tolerances that would reduce or adversely affect the end-use quality of the seed. Each of these factors may lower the oil or protein content of the seed thus reducing the economic return to the processor, or may lower the oil and meal quality, making it more difficult (or impossible) to process into acceptable final products. These grading factors appear as defects of the seed due to environmental conditions. The grading system classifies seed on the basis of the effect of the factors on the end-use quality of the product, but also the ability of the grower to produce seed free of these factors.

The grading system establishes maximum allowable tolerances for these grading factors listed below as outlined in Table 1 on page 1305 (page 1306 for rapeseed).

Grading Factors

Broken Seeds

Any broken canola that remains in the sample after cleaning and is otherwise sound is considered to be sound.

Colour

In assessing colour the following are considered:

• the general degree of maturity of the sample
• the amount and degree of discolouration, such as from weathering
• the proportion of damaged seeds, which are distinctly green or otherwise colour-damaged
• the amount of rime or light rime is considered in the overall appearance of the sample (rime is the pod lining that adheres to the seed)

Immaturity (green seeds) in a sample of canola occurs when the seed is harvested before it has reached physiological maturity. Mainly, immaturity increases the amount of chlorophyll in the oil. Chlorophyll is undesirable in finished products not only because of its colour and reduced shelf life but also because it might promote off-flavours. Oil losses and processing costs in the refining process increase with higher levels of chlorophyll. Colour is assessed for the cleaned samples. The general degree of maturity and the amount and degree of discolouration, such as weathering, is considered in conjunction with the proportion of damaged seeds present. Consideration is given to such factors as light rime or redness associated with growing conditions, which affect the general appearance but which are not extremely detrimental to quality. A Standard Sample of the grade is used to assist in evaluating colour. Standard Samples are prepared by the Chief Grain Inspector of the Canadian Grain Commission and represent, as nearly as possible, the minimum of each grade, considering the predominant factors in the current crop.

Conspicuous Admixture

Conspicuous admixture refers to seeds that remain in the sample after cleaning and are easily distinguished from canola without the use of magnification, including:

• domestic seeds such as flaxseed, yellow mustard, whole shrunken or broken kernels of other grains
• weed seeds such as cow cockle, lamb’s-quarters, cleavers, smartweed, ball mustard and pigweed

Representative portion for analysis is a minimum - 10 g (0.35 oz), optimum - 25 g (0.88 oz), and for export - 25 g.

Major factors affecting purity in canola are the presence of weed seeds and sclerotinia bodies, which are not separable from the samples. Weed seeds may adversely affect quality. Weed seeds usually have lower oil contents and higher free fatty acids and chlorophyll than canola. Many weed seeds are from the Cruciferae (mustard) family and contain oil with high levels of erucic acid and glucosinolates. Conspicuous admixture refers to inseparable foreign material handpicked from the cleaned sample such as yellow domestic mustard, pigweed, millet, cockle, or inert material which is conspicuous and readily identifiable from canola.

Contaminated Grain

Contaminated grain has been adulterated with pesticide treated seed, or is grain that has been treated with any desiccant, inoculant or fertilizer, or is grain that contains any evidence of fertilizer, e.g., fertilizer pellets, or other chemical substance.

Damaged Seeds

Damage in canola includes seeds that are:

• distinctly shrunken or shrivelled
• badly discoloured from mould
• completely and densely covered with rime
• excessively weathered, sprouted, distinctly green, heated or otherwise damaged.

The representative sample (minimum - 5 g (0.18 oz), optimum - 10 g, and export - 10 g) is handpicked of visually damaged seeds. Their percentage by weight is determined. The remaining portion is crushed in 100-seed strips for analysis (minimum - five strips, optimum - 10 strips, and export - 10 strips). A crush is made with only one pass of the roller under firm pressure. The count of the damaged seeds on the strip is converted to percentage by weight. This percentage is added to the percentage of visually damaged seeds and crushed damaged seed for total damage.

Sprouting may occur in canola when mature seed is subjected to high moisture or humidity either before or after harvest. The seeds germinate using oil as a source of energy and in doing so create undesirable free fatty acids. As the cotyledons develop, chlorophyll is manufactured. Sprouted seeds, therefore, have a lower oil content, higher chlorophyll and more free fatty acids than sound seeds. Frost damage in canola results in misshaped and shrivelled seeds, many with incomplete seed coats. Frost damaged seeds have lower oil and protein content and higher levels of free fatty acids.

Distinctly Green

Distinctly green tolerances are applied to crushed seeds that are a distinct green throughout. Pale green or immature seeds are taken into account in the evaluation of colour. Number of crushes (100-seed strips) for analysis is a minimum - five, optimum - 10, and for export - 10.

For certain samples, the subjective evaluation of green seeds and overall colour does not accurately estimate the chlorophyll present in the seed. A more accurate instrumental estimation of chlorophyll levels is available and may be considered in grading canola in the future.

Earth Pellets

Hard earth pellets are pellets that do not crumble under light pressure. Soft earth pellets are pellets that crumble under light pressure.

Ergot

Ergot is a plant disease producing elongated fungus bodies with a purplish-black exterior, a purplish-white to off white interior, and a relatively smooth surface texture. Representative portion for analysis is a minimum - 100 g, (3.5 oz) optimum - 500 g (1.1 lb), and for export - 500 g.

Ergot is a fungus, which attacks cereal grains, particularly rye, and results in disease bodies in place of the kernel of grain. Ergot does not infect canola plants, but is undesirable in canola intended for human purposes.

Excreta

There is a separate tolerance for insect excreta in canola.

Fertilizer Pellets

Fertilizer pellets are considered a contaminant in grain. Hard fertilizer pellets are pellets that do not crumble under light pressure. One pellet is one stone. Soft fertilizer pellets are pellets that crumble under light pressure.

Fireburnt

Samples that show any evidence of being charred or scorched by fire are considered fireburnt. Evidence includes odour, pieces of charred wood, etc. Fireburnt seeds pop when crushed. Samples considered fireburnt are graded Canola, Sample Canada, Account Fireburnt.

Foreign Material

Foreign material in canola includes anything that is not canola, such as stones, ergot, sclerotinia, conspicuous admixture and inconspicuous admixture.

Heated

Heated refers only to seeds that are distinctly or badly bin burnt. Heated seeds have a heated odour. Crushed seeds may be:

• black - badly bin burnt
• dark chocolate brown - distinctly heated
• light tan - slightly damaged from oxidation

If they have an odour or are present with brown or black crushed seeds, they are considered heated. Otherwise, they are included in Total damage, not heated.

The number of crushes (100-seed strips) for analysis is minimum - five, optimum - 10, and for export - 10. Five crushes are examined for evidence of heating. If no heated seeds are detected the crushes are assessed for other damage. If at least one heated seed is detected, an additional five crushes are assessed for heated seeds.

Heating occurs as a result of heat generated by microbial action and respiration in stored seeds. Damaged canola is more susceptible to heating during storage than sound seed. Heated seeds generally impart to the oil an unfavourable odour and colour, which is difficult to remove. Heating reduces the protein quality and increases free fatty acids. The presence of heated seed also indicates the increased probability of mould residues in the sample and therefore the threat of toxins. The Canadian grade regulations have very low allowable limits for heated seed.

Inconspicuous Admixture

Inconspicuous admixture is defined as seed of common wild mustard, domestic oriental mustard and domestic brown mustard that are not readily distinguishable from canola. The representative portion for analysis is a minimum - 1 g, optimum - 5 g, and for export - 5 g. To determine the percentage by weight of inconspicuous admixture, the sample should be analyzed with the aid of a microscope.

The seed coat characteristics of canola are very different from the mustards. This difference can only be determined with a microscope.

Insect Excreta

Representative portion for analysis is a minimum - 100 g, optimum - 500 g, and for export - 500 g.

(Note: Excreta, from insects feeding on canola plants, which is gathered along with seeds at harvest are undesirable).

Odour

There is no numeric tolerance for odour. Aspects considered include:

• the basic quality of the sample
• the type and degree of odour
• the presence of visible residue causing the odour

If Odour is the Grade Determinant and There is:	Then the Grade is:
A distinct objectionable odour not associated with the quality of the grain, but not heated or fireburnt	Canola, Sample Canada, Account Odour
A distinct heated odour	Canola, Sample Canada, Account Heated
A distinct fireburnt odour	Canola, Sample Canada, Account Fireburnt

Rime

Rime is the lining of the pod adhered to the seed. Seeds that are completely and densely covered with white rime are classed as damaged in any grade. Seeds with light rime sparsely covering the seed coat are:

• classed as sound if not otherwise damaged
• considered in the evaluation of colour

Representative portion for analysis is a minimum - 5 g (0.18 oz), optimum - 25 g, and for export - 25 g.

Sclerotinia Sclerotiorum

Sclerotinia sclerotiorum is a fungus producing hard masses of fungal tissue, called sclerotia. The sclerotia vary in size and shape, and have a dark black exterior, a pure white interior and a coarse surface texture. Representative portion for analysis is a minimum - 10 g, optimum - 25 g, and for export - 25 g.

Sclerotinia bodies are undesirable in canola since they are active fruiting bodies and are difficult to kill. Unfortunately, some sclerotinia bodies are formed in the same general size and shape as canola and are harvested along with the seed. These bodies are extremely difficult to remove.

Staghead

Staghead or white rust is a fungal disease of Brassica rapa canola. It affects the flowering parts of the plant, resulting in distorted antler-like structures that are often covered by white or grey powdery spores. For grading, staghead bodies are considered Conspicuous admixture. Representative portion for analysis is a minimum - 10 g, optimum - 25 g, and for export - 25 g.

Stones

Stones are hard shale, coal, hard earth pellets, hard fertilizer pellets and other non-toxic materials of similar consistency. In eastern Canada, grain containing 2.5% or less stones is graded Sample on account of stones. In western Canada, grain containing 2.5% or less stones is graded Rejected on account of stones. In eastern and western Canada, grain containing more than 2.5% stones is graded Sample Salvage. Representative portion for analysis is a minimum - 100 g, optimum - working sample and for export - working sample.

Admixtures of stones, filth, dirt, etc., with canola destined for crushing, is detrimental for food use.

Treated Seed

Pesticide treated seed is grain which has been adulterated with an agricultural chemical for agronomic purposes. These seed dressings contain a dye to render the treated grain visually conspicuous to a grain inspector. The colour of the dye varies depending on the type of treatment and the type of grain. The current colour standards for pesticide seed treatments of cereals and canola are pink/red and baby blue, respectively. The coatings or stains may appear greasy or powdery and the surface area distribution ranges from tiny flecks to compete coverage.

Independent Grading

If there is a disagreement between the producer and the primary elevator manager as to grade or dockage, either party may request an independent grade determination by an inspector of the Canadian Grain Commission. In such a situation, a representative sample of 750 grams (1.5 lb), satisfactory to both parties, is forwarded in a suitable container to the district inspector. Shipping charges must be prepaid, and the shipping tags clearly marked Subject to Inspector’s Grade and Dockage. The sample must be properly identified and bear the name of both parties who are to receive the inspector’s report. The sample will be graded and dockage assessed by the inspector, and both parties will be notified in writing of the grade and dockage. The Canadian Grain Commission provides this service for a fee.

Table 1. Primary Grade Determinants Table Canola, Canada (CAN)

*Grade Name	Standard of Quality		*Standard of Cleanliness Commercially Pure Seed
	*Variety	Degree of Soundness
No. 1 Canada	Any variety of canola equal to acceptable reference varieties	Reasonably well matured, sweet, good natural colour	Not more than 1.0% of other seeds that are conspicuous and that are not readily separable from canola, to be assessed as dockage
No. 2 Canada	Any variety of canola equal to acceptable reference varieties	Fairly well matured, sweet, reasonably good natural colour	Not more than 1.5% of other seeds that are conspicuous and that are not readily separable from canola, to be assessed as dockage
No. 3 Canada	Any variety of canola	May have the natural odour associated with low-quality seed, not distinctly sour, musty, rancid, or any odour that would indicate serious deterioration	Not more than 2.0% of other seeds that are conspicuous and that are not readily separable from canola, to be assessed as dockage
Grade, if No. 3 Specs not metCanada			Canola, Sample Canada Account Admixture

*Grade Name	Damage			Foreign Material						Inconspicuous Admixture %
	*Distinctly Green %	*Heated%	*Total%	Ergot%	Excreta%	Insect Excreta %	Sclerotinia %	Stones %	Conspicuous Admixture %
No. 1 Canada	2.0	0.1	3.0	0.05	0.02	0.1	0.05	0.05	1.0	5.0
No. 2 Canada	6.0	0.5	10.0	0.05	0.02	0.2	0.10	0.05	1.5	5.0
No. 3 Canada	20.0	0.5	10.0	0.05	0.02	0.2	0.10	0.05	1.5	5.0
Grade,if No. 3 specs not met	Canola Sample Canada Account Damaged	Canola Sample Canada Account Heated	Canola Sample Canada Account Damaged	Canola Sample Canada Account Ergot	Canola Sample Canada Account Excreta	Canola Sample Canada Account Excreta	Canola Sample Canada Account Admixture	2.5% or less Canola, Rejected (grade) Account Stones, or Canola, Sample Canada Account Stones Over 2.5% - Canola Sample Salvage	Canola Sample Canada Account Admixture	50.0% or less Canola Sample Account Admixture Over 50.0% - refuse screenings

Defined in the Canada Grain Regulations Schedule 111 Table XV1

Table 2. Primary Grade Determinants Table Rapeseed, Canada (CAN)

*Grade Name	Standard of Quality		*Standard of Cleanliness Commercially Pure Seed
	*Variety	Degree of Soundness
No. 1 Canada	Any variety of canola equal to acceptable reference varieties	Reasonably well matured, sweet, good natural colour	Not more than 1.0% of other seeds that are conspicuous and that are not readily separable from canola, to be assessed as dockage
No. 2 Canada	Any variety of canola equal to acceptable reference varieties	Fairly well matured, sweet, reasonably good natural colour	Not more than 1.5% of other seeds that are conspicuous and that are not readily separable from canola, to be assessed as dockage
No. 3 Canada	Any variety of canola	May have the natural odour associated with low-quality seed, not distinctly sour, musty, rancid, or any odour that would indicate serious deterioration	Not more than 2.0% of other seeds that are conspicuous and that are not readily separable from canola, to be assessed as dockage
Grade, if No. 3 Specs not metCanada			Rapeseed, Sample Canada Account Admixture

*Grade Name	Damage			Foreign Material						Inconspicuous Admixture %
	*Distinctly Green %	*Heated%	*Total%	Ergot%	Excreta%	Insect Excreta %	Sclerotinia %	Stones %	Conspicuous Admixture %
No. 1 Canada	2.0	0.1	3.0	0.05	0.02	0.1	0.05	0.05	1.0	5.0
No. 2 Canada	6.0	0.5	10.0	0.05	0.02	0.2	0.10	0.05	1.5	5.0
No. 3 Canada	20.0	2.0	20.0	0.05	0.02	0.3	0.15	0.05	2.0	5.0
Grade,if No. 3 specs not met	Rapeseed Sample Canada Account Damaged	Rapeseed Sample Canada Account Heated	Rapeseed Sample Canada Account Damaged	Rapeseed Sample Canada Account Ergot	Rapeseed Sample Canada Account Excreta	Rapeseed Sample Canada Account Excreta	Rapeseed Sample Canada Account Admixture	2.5% or less Rapeseed, Rejected (grade) Account Stones, or Rapeseed, Sample Canada Account Stones Over 2.5% - Rapeseed Sample Salvage	Rapeseed Sample Canada Account Admixture	50.0% or less Rapeseed Sample Account Admixture Over 50.0% - refuse screenings

* Defined in the Canada Grain Regulations Schedule 111 Table XX11

Crop Quality Information

The Grain Research Laboratory of the Canadian Grain Commission monitors certain quality characteristics of the Canadian canola crop. This information is made available to growers and the trade in published reports. Each fall, the Commission conducts a survey of oil, protein, chlorophyll, fatty acid composition and glucosinolate levels in the new crop and publishes the information in the Western Canadian Oilseeds bulletin. The quality factors for canola cargoes are also determined and summaries are provided monthly in the Grain Commission’s Exports of Canadian Grain and Wheat Flour bulletin.

References