Language selection

Government of Canada / Gouvernement du Canada

Search

Corn: Grading factors

Chapter 17. Corn (PDF, 766 KB)
Full list of grading factors

B

Blue-eye mould (BEM)

Germs of kernels appear dark blue with mould, or there may be just a visible mouldy blue streak under the hull of the germ. In the second case, peel back the hull from the germ to examine the germ.

Blue-eye mould is included in the tolerance for Damage.

C

Caramelized kernels

Caramelized kernels are kernels that were very immature when dried at a high temperature in a dryer, and the heat has turned the kernel to a scorched colour similar to that of heated kernels. The outer hull of the kernel may be peeled off showing a slightly damaged kernel inside. These kernels are classed as Damaged.

Classes

Corn is classed as yellow, white, or mixed. The class forms part of the grade name; for example, Corn, Sample CW Yellow Account Heated.

Samples of yellow and white corn containing less than 95.0% of one class are designated Mixed; for example, Corn number 1 CE Mixed.

Contaminated grain

Important: Wear gloves and a mask to handle any sample that is suspected of containing contaminated grain.

Grain is contaminated for the purposes of the Canada Grain Act if the grain contains any substance in sufficient quantity that the grain is either

  1. adulterated for the purposes of the Food and Drugs Act; or 
  2. contaminated within the meaning of the regulations made under section 51 of the Safe Foods for Canadians Act.

Procedures

If a sample is suspected of being contaminated, the sample should be submitted to the Canadian Grain Commission. Determination as to whether grain is contaminated will be made by the Grain Research Laboratory in consultation with the Chief Grain Inspector for Canada. Samples deemed to be contaminated are graded: Corn, Sample Condemned.

Cracked corn and foreign material (CCFM)

Cracked corn and foreign material includes any of the following:

  • All material including kernels and pieces of kernels of corn or any other grains which pass through a number 12 round-hole sieve or, for samples with a moisture level over 25.0%, through the number 14 round-hole sieve
  • All foreign material other than stones handpicked from the sample, including pieces of cobs that were not removed by sieving

Procedures

Important: Follow procedures for assessing dockage.

Note: Because breakage occurs during handling at terminal elevators, round down percentages by weight of CCFM to the nearest whole number on all officially sampled and inspected domestic or export shipments from a terminal elevator.

For example, a sample containing 4.7% CCFM by weight is recorded as containing 4% CCFM for grading purposes only on officially sampled and inspected shipments from a terminal elevator.

D

Damage (DMG)

Damaged kernels include whole kernels or pieces of kernels which are

  • Affected by blue-eye mould and other types of moulds
  • Sprouted
  • Ground-damaged
  • Weathered
  • Diseased
  • Frosted
  • Scorched, from a drier
  • Heated, naturally, or from a drier, or caramelized
  • Rotted

E

Earth pellets (EP)

Excreta (EXCR)

Excrement from any animal including mammals, birds and insects.

Important : Wear gloves and a mask to handle any samples that you suspect may contain excreta.

Extraneous material

Can be defined as glass, metal, wood, plastic or any other material not already defined in the Official Grain Grading Guide.

F

Fertilizer pellets (FERT PLTS)

Fertilizer pellets are a manufactured plant nutrient product used by producers in the production of grain. They are typically small, round or irregular shaped and usually white, grey, brown, pink or reddish in colour.

Procedures

  • Handpick any fertilizer pellets and determine the concentration basis the net working sample.
  • Fertilizer pellets are assessed as stones when the concentration does not exceed 1.0% of the net sample weight.
  • Samples containing fertilizer pellets in excess of 1.0% of the net sample weight are graded Corn, Held IP Suspect Contaminated Grain.

Fireburnt (FBNT)

Fireburnt kernels are kernels charred or scorched by fire. A cross-section of a fireburnt kernel resembles charcoal with numerous air holes. The air holes result in a low weight kernel which crumbles easily under pressure.

Procedures

Samples of corn containing fireburnt kernels are graded Corn, Sample CW/CE (class) Account /Fireburnt.

Foreign material (FM)

Cracked corn and foreign material (CCFM).

H

Heated (HTD)

Heated kernels have at least one of the following characteristics:

  • Whole kernels or pieces of kernels which range in colour from amber to dark brown over the entire kernel
  • Kernels which are totally discoloured by fermentation and show no natural colour on the crowns or dorsals, or both
  • The germ of the kernel is amber to dark brown and is severely puffed in the germ area when heated in a drier
  • Heated seeds of other grains are included in the tolerance for Heated

If kernels exhibit none of the above characteristics, but are not whole or sound, they are classed as Damaged.

Note: Cracked corn and foreign material that is heated is included with heated corn for grade assessment.

O

Odour (ODOR)

There is no numeric tolerance for odour. Consider

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

Grains grading number 1 through 4 must be cool and sweet. Corn grading number 5 may have a slight odour associated with the low quality, but the odour cannot be sour or musty.

Heated, fireburnt and odour for corn
If odour is the grade determinant and there is: Then the grade is:
An excessive objectionable odour not associated with the quality of the grain, but not heated or fireburnt Corn, Sample CW/CE Account Odour
An excessive heated odour Corn, Sample CW/CE Account Heated
An excessive fireburnt odour Corn, Sample CW/CE Account Fireburnt

R

Rotted (ROT)

Rotted kernels are whole kernels or pieces of kernels which are visibly in advanced stages of decomposition and feel spongy under pressure. Rotted kernels are included in the percentage of heated kernels for grade assessment.

S

Stones (STNS)

Stones are hard shale, coal, hard earth pellets, and any other non toxic materials of similar consistency. Fertilizer pellets are assessed as stones when constituting 1.0% or less of the net sample weight. (See Fertilizer pellets for specific procedures to be followed when samples contain fertilizer pellets.)

Procedures

  1. Handpick stones from a representative portion of the cleaned sample.
  2. Determine stone concentration in the net sample.
  • Samples of grain grown in western Canada samples of grain containing stones in excess of “basic grade” tolerances, up to 2.5% are graded Corn, Rejected “basic grade” Account Stones. The “basic grade” refers to a grade established in the Canada Grain Regulations (grades listed in the first column in grade determination tables) that would have been assigned to the sample if it contained no stones.
  • Samples of grain grown in eastern Canada samples of grain containing stones in excess of grade tolerances are degraded to lower grades. Samples containing stones in excess of the tolerance of the lowest grade established by regulation up to 2.5% are graded Corn, Sample CE (class) Account Stones.
  • Samples of western and eastern Canadian grain containing more than 2.5% stones are graded Corn, Sample Salvage.
  • Examples: Western Canada
    Excerpt from grade determination tables for Corn, Canada Western, White, Yellow or Mixed
    Grade name Stones %
    number 1 CW 0.15
    number 2 CW 0.15
    number 3 CW 0.15
    number 4 CW 0.15
    number 5 CW 0.15

    Basic grade: Corn, number 2 CW Yellow
    Reason for basic grade: 3% Cracked corn and foreign material

    Grade in Western Canada if stones found
    If the above sample contained Grade in western Canada
    0.5% stones Corn, Rejected number 2 CW Yellow Account Stones
    3.0% stones Corn, Sample Salvage
    Examples: Eastern Canada
    Excerpt from grade determination table for Corn, Canada Eastern, White, Yellow or Mixed
    Grade name Stones %
    number 1 CE 0.15
    number 2 CE 0.15
    number 3 CE 0.15
    number 4 CE 0.15
    number 5 CE 0.15

    Basic grade: Corn, number 2 CE Yellow
    Reason for basic grade: 3.0% Cracked corn and foreign material

    Grade in Eastern Canada if stones found
    If the above sample contained Grade in eastern Canada
    0.5% stones Corn, Sample CE Yellow Account Stones
    3.0% stones Corn, Sample Salvage

T

Test weight (TWT)

Test weight is the weight of a known volume of grain expressed in kilograms per hectolitre. For procedures, see Chapter 1 of this guide, Test weight.

Test weight on corn is determined prior to removal of cracked corn and foreign material. When the Terms of Delivery or terms of a contract state that dockage can be deducted, then test weight is determined after the removal of dockage.

Treated seed and other chemical substances

Treated seed

Treated seed is grain that has been adulterated with an agricultural chemical for agronomic purposes. The types of agricultural chemicals used to treat seed include pesticides, fungicides and inoculants. These seed dressings contain a dye to render the treated seed visually conspicuous. The colour of the dye varies depending upon the type of treatment and the type of grain. The current Canadian colour standard for pesticide and fungicide seed treatments for cereal (including corn) is red or pink. The colour standard for pesticide and fungicide seed treatments for canola is blue; however, green has also been used. Pulse crop (including soybeans) pesticide and fungicide seed treatments are typically blue or green. The coatings or stains may appear greasy or powdery and the surface area covered may range from tiny flecks to complete coverage.

Other chemical substances

Other chemical substances refers to any chemical residues either adhering to the kernel or remaining in the sample and to samples having a chemical odour of any kind.

Important: Wear gloves and a mask to handle any samples that you suspect may contain contaminated grain

Procedures

If a sample is suspected of being coated with a pesticide, desiccant, inoculant or if the sample contains evidence of any foreign chemical substance other than fertilizer pellets, the sample shall be graded Corn, Held IP Suspect Contaminated Grain.

V

Variety (VAR)

Corn is graded without reference to variety.

"Page details"

Date modified: