1 Grain impurities:
1.1 Broken grains (50%)
1.2 Grains damaged by pests (50%)
1.3 Flattened grains
1.4 Shrunken grains
1.5 Sprouted grains
1.6 Damaged grains
1.7 Grains and seeds of other cultivated plants
2 Waste impurities
2.1 All that passes through a 2.5 mm sieve
2.2 Mineral impurities
2.3 Organic impurities
2.4 Seeds of wild growing plants
2.5 Spoiled grains of maize
2.6 Harmful impurities - Ergot and smut - Darnel rye-grass, rose stagger, sophora stagger, thermopsis, coronilla, fluffy fruited heliotrope, trichodesma (Trichodesma incanum), castor seeds
2.7 Grains and seeds of other cultivated plants (for the food maize)
2.8 Grains and seeds of other cultivated plants (belonging by the nature of their damage to waste impurities - for the fodder maize)
Physical quality criteria
1. Specific Weight KG/HL
2 Moisture(Max 15%), %
3 Grains Impurities (on sieve 2.5 mm)(Max 15%), %
3.1 Broken Grains (50%), %
3.2 Grains damaged by pests (50%), %
3.3 Pressed grains
3.4 Shrivelled grains
3.5 Sprouted Grains (Max 1%), %
Grains heated by drying
3.2 Grains of other cereals, %
Grains damaged by frost
3.4 Miscellaneous Impurities (max 5%), %
3.4.1 Extraneous seeds, %
- Seeds of plants (weed seeds …), %
- Seeds other then cereals, %
- Noxious (toxic) seeds, %
3.4.2 Damaged grains, %
- Unfit for human consumption, %
- Extreme drying , %
- Grains attacked by wheat-midge (more then 50%surface), %
3.4.3 Mineral impurities, %
- All matter on sieve of 3.5 mm, %
- All matter passing through sieve of 1.0 mm , %
- Stones, sand, fragment of straw and other impurities (Sieve 1 mm), %
3.4.4 Husks, %
3.4.7 Dead insects, %
3.4.8 Fragments of insects, %
4.1 Sound and fair merchantable
4.2 Free from abnormal smell
4.3 Free from live pests
4.4 Colour specific to Maize
Damaged grains (with changed seed coat color and endosperm fm creamy to light brown in color, also with darkened germ fm light brown to dark brown in color, without visual absence of mouldy bloom on the surface and under seed coat in the germ area)
Grains and seeds of other cultivated plants belonging by the nature of their damage to grain impurities (for the fodder maize)
Spoiled grains of maize (with decidedly spoiled endosperm from light brown to dark brown in color; with darkened and (or) mouldy germ with visual absence of mouldy bloom on the surface and (or) under seed coat in the germ area)
Analysis Unit EC limits
1 Moisture % 14.0
2 Total percentage of matter other than basic cereals
of unimpaired quality % 8.0
2.1 Broken Grains (Sieve with a 4.5 mm round mesh) % 2.0
2.2 Grains Impurities % 4.0
2.2.2 Grains of other cereals %
2.2.3 Grains damaged by pests %
2.2.5 Grains heated by drying %
2.3 Sprouted Grains % 1.0
2.4 Miscellaneous Impurities (Schwarzbesatz) % 1.0
2.4.1 Extraneous seeds %
2.4.2 Damaged grains %
2.4.3 Extraneous matter, Husks, Dead insects, Fragments of insects %
3.1 Sound and fair merchantable
3.2 Free from abnormal smell
3.3 Free from live pests #/kg
Corn DSTU 4525-2006.
Ordinary export quality
- Moisture: 14.5 pct
- Broken Grains: max 5 pct
- Damaged Grains: max 5 pct
- Foreign matter: max 2 pct
Sound and fair merchantable
Free from abnormal smell
Free from live pests
Corn US grades
YELLOW CORN GRADE # 2
Moisture 14% max
Heat damaged kernels 0.5% max
Total damaged kernels 3.5% max
Protein 9% min
Admixture 2.5% max
Aflatoxin total 20 PPB
YELLOW CORN GRADE # 3
Moisture 14.5% max
Heat damaged kernels 1% max
Total damaged kernels 7% max
Protein 8% min
Admixture 2.5% basis
Aflatoxin total 20 PPB
Hectolifters 68 KC min
WHITE CORN GRADE # 2
Moisture 14% max
Protein 10% min
GRAIN INSPECTION HANDBOOK
Book II, Corn, 10/1/90
4.1 GRADES AND GRADE REQUIREMENTS
Corn is divided into three classes based on color: Yellow corn. White corn. and Mixed corn. Each class is divided into five U.S. numerical grades and U.S. Sample grade. Special grades are provided to emphasize special qualities or conditions affecting the value and are added to and made a part of the grade designation. They do not affect the numerical or sample grade designation.
Table No. 1 Grades and Grade Requirements
Grade min tw bushel (ponds) I Kernels Total corn and foreign
U.S NO. 1 56.0 1 3. I 2
U.S No. 2 54.0 2 5. 130
U.S No. 3 52.0 5 7. 40
U.S No. 4 49.0 0 10. 50
U.S No. 5 46.0 0 15.
U.S Sample grade:
U.S. Sample grade is corn that:
(a) Does not meet the requirements for the grades U.S. Nos. 1, 2, 3. 4, or 5: or
(b) Contains 8 or more stones which have an aggregate weight in excess of 0.20% of the sample weight, 2 or more pieces of glass, 3 or more crotalaria seeds (Crotalaria spp.). 2 or more castor beans (Riginus communis L.), 4 or more are particles of an unknown foreign substance (s)) or a commonly recognized harmful or toxic subtance(s), 8 or moreore cocklexurs spp.) or similar ——Is singly or in combination, or anual filth in excess of 0.20 percent in 1,000 grams; or (c) Has a musty, sour, or commercially - objectionable foreign odor: or (d) Is heating or otherwise - of distinctly low quality.
4.2 GRADE DESIGNATIONS
Use the following guidelines when assigning grades on pan tickets and certificates.
A. The letters U.S,
B. The abbreviation No. and the number of the grade or the words Sample grade,
C. The words or better when applicable,
D. The name of the class and kind of grain,
E. The special grade Flint when applicable,
F. The special grade (Flint and Dent) (when applicable) along with the approximate percentage of Flint corn,
G. The special grade (Infested) when applicable, and
H. The special grade (Waxy) (when applicable) shall be shown last in the grade designation.
When more than one special grade applies, list them in alphabetical order. When certificating Mixed corn, record the percent of each corn in order of predominance in the (Remarks) section to the nearest tenth percent.
Examples: U.S. No. 2 White corn, Infested
U.S. No. 3 or better Yellow corn
U.S. Sample grade Yellow corn. Infested
4.3 SPECIAL GRADES AND SPECIAL GRADE DESIGNATIONS
Special grades draw attention to unusual conditions in grain and are part of the grade designation. The definitions and examples of the designations for special grades in corn are:
A. FLINT CORN. CORN THAT CONSISTS OF 9S PERCENT OR MORE OF FLINT CORN. Example: U.S. No. 3 Yellow corn, Flint
B. FLINT AND DENT CORN. CORN THAT CONSISTS OF A MIXTURE OF FLINT AND DENT CORN CONTAINING MORE THAN 5.0 PERCENT BUT LESS THAN 95 PERCENT OF FLINT CORN. Example: U.S. No. 2 Yellow corn, Flint and Dent, Flint corn 35%
C. INFESTED-CORN. Corn that is infested with live weevils or other live insects injurious to stored grain. Example: U.S. No. 2 Yellow corn. Infested
D. WAXY CORN. CORN THAT CONSISTS OF 95 PERCENT OR MORE WAXY CORN. Example: U.S. No. 1 White corn, Waxy
4.4 The Official U.S. Standards for Grain provide for an OPTIONAL GRADE optional grade designation, commonly referred to as (or DESIGNATION better) Upon the request of an applicant, corn may be
certified as U.S. No. 2 or better, U.S. No. 3 or better, etc. An (or better) grade designation cannot be applied
to a U.S. No. 1 grade designation. Book III provides specific guidelines for applying the (or better) grade
designation to ship lots, unit trains, and lash barges. Example: U.S. No. 3 or better Yellow corn
4.5 DISTINCTLY LOW QUALITY. THE DETERMINATION OF DISTINCTLY OF LOW QUALITY IS HADE ON THE BASIS OF THE LOT AS A WHOLE DETERMINATION AT THE TIME OF SAMPLING WHEN A CONDITION EXISTS THAT MAY OR MAY NOT APPEAR IN THE REPRESENTATIVE SAMPLE AND/OR THE SAMPLE AS A WHOLE.
CERTAIN QUALITY DETERMINATIONS. EACH DETERMINATION OF RODENT PELLETS, BIRD DROPPINGS. OTHER ANIMAL FILTH, BROKEN GLASS. CASTOR BEANS, COCKLEBURS, CROTALARIA SEEDS. DOCKAGE. GARLIC. LIVE INSECT INFESTATION, LARGE STONES. MOISTURE. TEMPERATURE, AND UNKNOWN FOREIGN SUBSTANCE(S), AND A COMMONLY RECOGNIZED HARMFUL OR TOXIC SUBSTANCE(S) IS HADE ON THE BASIS OF THE SAMPLE AS A WHOLE. WHEN A CONDITION EXISTS THAT MAY NOT APPEAR IN THE REPRESENTATIVE SAMPLE, THE DETERMINATION MAY BE MADE ON THE BASIS OF THE LOT AS A WHOLE AT TOE TIME OF SAMPLING ACCORDING TO PROCEDURES PRESCRIBED IN FGIS INSTRUCTIONS.
ALL OTHER DETERMINATIONS. EACH DETERMINATION OF CLASS. DAMAGED KERNELS, HEAT-DAMAGED KERNELS, WAXY CORN, FLINT CORN, AND FLINT AND DENT CORN IS MADE ON THE BASIS OF THE GRAIN AFTER THE REMOVAL OF THE BROKEN CORN AND FOREIGN MATERIAL. OTHER DETERMINATIONS NOT SPECIFICALLY PROVIDED FOR UNDER THE GENERAL PROVISIONS ARE MADE ON THE BASIS OF THE GRAIN AS A WHOLE, EXCEPT THE DETERMINATION OF ODOR IS MADE ON EITHER THE BASIS OF THE GRAIN AS A WHOLE OR THE GRAIN WHEN FREE FROM BROKEN CORN AND FOREIGN MATERIAL.
Table No. 2 . Basis of Determination
FACTORS DETERMINED BEFORE THE REMOVAL OF BROKEN CORN AND FOREIGN MATERIAL
FACTORS DETERMINED AFTER THE REMOVAL OF BROKEN CORN AND FOREIGN MATERIAL
Distinctly low quality
Kind of grain
U.S. Sample grade factors
Test weight per bushel Class
Flint and dent corn
The following sections of this chapter are arranged in a sequence typically followed in the inspection and grading of corn.
4.6 Corn is defined as: DEFINITION OF CORN GRAIN THAT CONSISTS OF 50 PERCENT OR MORE OF WHOLE KERNELS OF SHELLED DENT CORN AND/OR SHELLED FLINT CORN (ZEA MAYS L.) AND MAY CONTAIN NOT MORE THAN 10.0 PERCENT OF OTHER GRAINS FOR WHICH STANDARDS HAVE BEEN ESTABLISHED UNDER THE UNITED STATES GRAIN STANDARDS ACT.
Whole kernels are kernels with one-fourth or less of the kernel removed. Other grains for which standards have been established are barley, flaxseed, oats, rye, sorghum, soybeans, sunflower seed, triticale, and wheat.
Basis of Determination. Normally, a visual appraisal of the sample is sufficient to determine if it meets the definition of corn. However, if an analysis is necessary make the determination before the removal of broken corn and foreign material on a portion of approximately 250 grams. If the sample does not meet the definition of corn. examine it further to determine if it is:
A. Another grain for which standards have been established or
B. Not standardized grain. No further analysis is necessary on a sample designated as not standardized grain unless a specific factor test is requested. Corn developing a high temperature from excessive respiration is considered heating. Heating corn, in its final stages, will usually have a sour or musty odor. Care should be taken not to confuse corn that is heating with corn chat is warn and moist because of storage in bins, railcars, or other containers during hot weather.
Basis of Determination. Determine heating on evidence obtained at the tine of sampling or on the basis of the sample as a whole.
Certification. Grade heating corn as U.S. Sample grade and record the word (Heating) on the work record and in the (Remarks) section of the certificate.
Basis of Determination. Determine odor on evidence obtained at the time of sampling and on the sample either before or after the removal of broken corn and foreign material.
Table No. 3 . Odor Classification Examples
SOUR MUSTY COMMERCIALLY OBJECTIONABLE FOREIGN ODORS
Boot Ground Animal hides
Fermenting, Insect (acrid)
Pigpen Insect, Moldy Decaying animal and vegetable Batter
Fertilizer, Fumigant, Insecticide
Oil products, Skunk
Commercially Objectionable Foreign Odors. Commercially objectionable foreign odors are odors foreign to grain that render it unfit for normal commercial usage.
Fumigant or insecticide odors are considered commercially objectionable foreign odors if they linger and do not dissipate. When a sample of corn contains a fumigant or insecticide odor that prevents a determination as to whether any other odor(s) exists, apply the following guidelines:
A. Original Inspections. Allow the work portion to aerate in an open container for a period not to exceed 4 hours.
B. Reinspections. Appeal, and Board Appeal Inspections. Allow unworked file samples and new samples to aerate in an open container for a period not to exceed 4 hours. The 4-hour aeration requirement does not apply when the original work portion was aerated and retained as the final file. Consider the sample as having a commercially objectionable foreign odor if the fumigant or insecticide odor persists
based on the above criteria.
Final Determination. The inspector(s) is responsible for making the final determination for all odors. A consensus of experienced inspectors is used, whenever possible, on samples containing marginal odors. The consensus approach is not required if no odor or a distinct odor is detected.
Certification. Grade corn containing a (distinct) musty, sour, or commercially objectionable foreign odor as U.S. Sample grade. Record the words (Musty.)(Sour,) or Commercially Objectionable Foreign Odor on the work record and in the "Remarks" section of the certificate.
4.9 WATER CONTENT IN GRAIN AS DETERMINED BY AN APPROVED DEVICE MOISTURE ACCORDING TO PROCEDURES PRESCRIBED IN FGIS INSTRUCTIONS.
Basis of Determination. Determine moisture before the removal of broken corn and foreign material on a portion of exactly 250 grams.The procedures for performing a moisture determination using the Motomco moisture meter are described in book II, chapter 1. section 1.9.
Certification. Record the percent of moisture on the work record and the certificate to the nearest tenth percent.
4.10 THE WEIGHT PER WINCHESTER BUSHEL (2.150.42 CUBIC INCHES) Test weight per bushel AS DETERMINED USING AN APPROVED DEVICE ACCORDING TO PROCEDURES PRESCRIBED IN FGIS INSTRUCTIONS.
Basis of Determination. Determine test weight per bushel before the removal of broken corn and foreign material on a portion of approximately 1-1/8 to 1-1/4 quarts. The procedures for performing the test weight per bushel determination are described in book II, chapter 1, section 1.10.
Certification. Record test weight results on the work record as displayed on the electronic scale or in whole and half pounds. Disregard fractions of a half pound. Record the test weight per bushel on the certificate in whole and half pounds.
4.11 INFESTED CORN. Corn shall be considered infested if it contains live weevils or other live insects injurious to scored grain.
The presence of any live weevil or other live insects injurious to stored grain found in the work sample
indicates the probability of infestation and warns that the corn must be carefully examined to determine if it is infested. In such cases, examine the work sample and the file sample before reaching a conclusion as to whether or not the corn is infested. Do not examine the file sample if the work sample is insect free.
Live weevils include rice weevils, granary weevils, maize weevils, cowpea weevils, and lesser grain borers. Other live insects injurious to stored grain shall include grain beetles, grain moths, vetch bruchids. and larvae. (See U.S. Department of Agriculture. Agricultural Research Service, Agricultural Handbook No. 500.)
Basis of Determination. Determine infestation on the lot as a whole and/or the sample as a whole. For specific guidelines, see table No. 5 and Book I. Grain Sampling.
Table No. 4 . Insect Infestation Guide
SAMPLE DESIGNATION INFESTED LEVEL 1/
REPRESENTATIVE SAMPLE - Applies to 2 Iw 3
submitted samples, lots probe-sampled, Or
and D/T-sampled railcars/trucks. Examine 1 Iw + 5 oli 3
work portion and file sample. (Do not Or
examine file sample if work portion is 10 oli 3
LOT AS A WHOLE (STATIONARY) - Applies Same
at the time of sampling for lots probe-sampled.
LOT AS A WHOLE (CONTINUOUS LOADING) - 2/ Same
- each railcar when inspected under
• each subsample for sacked grain lots.
• each component sample for barge lots
and shiplots. 3/
- 3 Iw — Live weevil, oli — Other live insects injurious to scored grain.
1/ Samples containing infestation at these levels are infested.
2/ Minimum sampling rate for online operations is 500 grams per 2,000 bushels.
3/ Minimum component size is approximately 10.000 bushels.
Certification. When applicable, record the word (Infested) on the work record and the certificate in accordance with Section 4.2, Grade Designations.
4.12 Consider corn distinctly low quality when it is DISTINCTLY obviously of inferior quality and the existing grade LOW QUALITY factors or guidelines do not accurately reflect the inferior condition.
Basis of Determination. Use all available information to determine whether the corn is of distinctly low quality. Determine distinctly low quality on the lot or the sample as a whole. Table No. 5 shows the criteria and the appropriate basis of determination.
Large Debris. Corn containing two or more stones, pieces of glass, pieces of concrete, or other pieces of wreckage or debris which are visible to the sampler but are too large to enter the sampling device is considered distinctly low quality.
Other Unusual Conditions. Corn that is obviously affected by other unusual conditions which adversely affect the quality of the corn and cannot be properly graded by use of the grading factors specified or defined in the standards is considered distinctly low quality.
Corn suspected of containing diatomaceous earth (DE) is considered distinctly low quality unless the applicant specifically requests an examination to verify the presence of DE. If the laboratory examination verifies that the corn contains DE, then the corn is not considered distinctly low quality due to DE. Refer to Program Directive 918.49 for additional information regarding the testing of corn for DE.
Certification. Grade distinctly low quality corn as U.S. Sample grade. Record the words (Distinctly Low Quality) and the reason(s) why on the work record and in the (Remarks) section of the certificate.
4.13 Basis of Determination. Determine U.S. Sample grade U.S. SAMPLE criteria before the removal of broken corn and GRADE CRITERIA foreign material based on a work portion of approximately 1.000 to 1,050 grams. Table No. 5 shows the criteria and corresponding interpretive line slides, tolerance limits.
and the appropriate basis of determination.
Table No. 5 • U.S. Sample Grade Criteria
SAMPLE BASIS LIMITS 1/
LOT BASIS 2/
Excess of limit N/A
for U.S. No. 5-
Animal filth OF-1.0 Excess of 0.20% N/A
Castor beans QF-3.0 2 or more N/A
Cockleburs OF-6.0 8 or more N/A
Crotalaria seeds OF-8.0 3 or more N/A
2 or more N/A
8 or more and in excess N/A
of 0.20% by weight
Unknown foreign OF-31.0 4 or more N/A
Large debris 4
N/A 2 or more
1/ Record count factors to the nearest whole number.
2/ The entire sample of a submitted sample is considered as the lot.
3/ Consider feed pellets as foreign material not unknown foreign substance.
4 For Distinctly Low Quality, see section 6.12.
Certification. Grade corn U.S. Sample grade when one or more of the limits in table 5 are exceeded. Record the reason(s) why on the work record and in the (Remarks) section of the certificate.
4.14 BROKEN CORN AND BROKEN MATIRIAL
BROKEN CORN. ALL MATTER THAT PASSES READILY THROUGH A 12/64 ROUND-HOLE SIEVE AND OVER A 6/64 ROUND-HOLE SIEVE.
FOREIGN MATERIAL. ALL MATTER THAT PASSES READILY THROUGH A 6/64 ROUND-HOLE SIEVE AND ALL MATTER OTHER THAN CORN THAT REMAINS ON TOP OF THE 12/64 ROUND-HOLE SIEVE.
BROKEN CORN AND FOREIGN MATERIAL. ALL MATTER THAT PASSES READILY THROUGH A 12/64 ROUND-HOLE SIEVE AND ALL MATTER OTHER THAN CORN THAT REMAINS IN THE SIEVED SAMPLE AFTER SIEVING ACCORDING TO PROCEDURES PRESCRIBED IN FGIS INSTRUCTIONS.
Basis of Determination. Determine the factors broken corn (BC) and foreign material (FH) on a portion of approximately 1,000 to 1,050 grams. Combine the results from these two determinations for the grading factor broken corn and foreign material (BCFH). The approved method for determining the factor BCFH is the method described in this section. Hand sieving the work sample using a 12/64-inch round-hole sieve or a 6/64-inch round-hole sieve is not recognized as an official method.
Determining BCFM with the Carter Dockage Tester. Using the procedure described in book II. chapter 1, section 1.11, set up the Carter dockage tester as follows:
A. Set the air control at I.
B. Sec the feed control at 10.
C. Use no riddle.
D. Insert the Number 3 sieve (combination 12/64 and 6/64) in the cop sieve carriage.
E. Use no sieve in the middle sieve carriage.
F. Use no sieve in the bottom sieve carriage.
BC consists of all matter that passes through the 12/64 round-hole sieve and over the 6/64 round-hole sieve. Weigh this material and calculate the percentage.
FH consists of all matter passing through the 6/64 round-hole sieve and all matter other than corn found in the sieved sample.
The true percentage of FM cannot be determined until the sieved sample is handpicked. Handpick the sieved sample by pouring the sample onto the picking surface and removing all matter other than corn. Consider sweet corn and popcorn as FH. (Reference: Interpretive Line Slide No. OF-7.4.) Combine the handpicked FM with the material from the bottom catch pan. Weigh and calculate the percentage.
To determine the percentage of BCFM, add the total weight of the BC and FM and divide by the weight of the portion size. The result is the (total) percentage of BCFM.
To avoid repeating operations, check the material found in the BCFH sieve catch pans for live weevils and other live insects injurious to stored grain, scones, distinctly low quality, and other sample grade factors. Live weevils, other live insects injurious to scored grain, and sample grade factors are considered FM but, when present in sufficient quantities, are considered in the determination of U.S. Sample grade and/or the special grade Infested.
Adjustment of Factors. In certain instances, the sum of BC and FM in corn, due to rounding, will not equal the percentage of BCFM recorded on the certificate. When this occurs, it is necessary to adjust the component nearest a midpoint (e.g.; .05, .15, .25, .35, etc.) by adding or subtracting 0.1.
Original sample weight - 1,012 grams
Weight of BC - 38.34 grams
Weight of FM - 2.64 grams
Weight of BCFM - 40.98 grams
STEP 1 - (38.34 -: 1,012) x 100 - 3.78% BC (rounded 3.8%)
STEP 2 - (2.64 -: 1,012) x 100 = 0.26% FM (rounded 0.3%)
STEP 3 - (40.98 -: 1,012) = 4.04% BCFM (rounded 4.0%).
Since the sum of the rounded BC and FM results (3.8% BC -: 0.3% FM a 4.1%) does not equal the rounded BCFM results (4.0% BCFM), an adjustment of -0.1 is needed. In this instance, the rounded result for FM (0.3%) is adjusted downward to 0.2% because the unrounded result (0.26%) is nearer to a midpoint (0.25) than the unrounded result for BC.
Certification. Record the percentage of BC and the percentage of FM separately to the nearest tench on the work record and in the (Remarks) section of the certificate for nonexpert shipments and on the loading log or work record for export shipments. In the (Factor) block of the certificate, record the total percentage of BCFH to the nearest tenth percent.
At this point, determinations have been made for odor, test weight, moisture, BCFM, infestation, and sample grade factors. Now divide the work sample into fractional portions for those determinations required after the removal of broken corn and foreign material. Table No. 6 shows portion sizes and Chart No. 1 illustrates how to divide the sample into fractional pares using the Boerner divider.
Table No. 6 - Approximate Analytical Portion Sizes
Flint corn 250
Flint and dent corn 250
Kind of grain 250
re the removal
1/ Factor determined before
Chart No. 1 . Dividing the Work Sample
DAMAGED KERNELS HEAT—DAMAGED KERNELS
Corn is divided into the following three classes:
A. YELLOW CORN. CORN THAT IS YELLOW-KERNELED AND CONTAINS NOT MORE THAN 5.0 PERCENT OF CORN OF OTHER COLORS. YELLOW KERNELS OF CORN WITH A SLIGHT TINGE OF RED ARE CONSIDERED YELLOW CORN.
The term "yellow kernels of corn with a slight tinge of red" includes kernels which are yellow and/or light red in color and kernels which are yellow and dark red in color provided the dark red color covers less than 50 percent of the kernel. Yellow and red kernels in which the dark red color covers 50 percent or more of the kernel are considered "Corn of Other Colors." (Reference: Interpretive Line Slide No. OF-7.5.)
B. WHITE CORN. CORN THAT IS WHITE-KERNELED AND CONTAINS NOT MORE THAN 2.0 ERCENT OF CORN OF OTHER COLORS. WHITE KERNELS OF CORN WITH A SLIGHT TINGE OF LIGHT STRAW OR PINK COLOR ARE CONSIDERED WHITE CORN.
White corn with a slight tinge of light straw applies to all White corn, except corn found to be waxy. For the specification pertinent to waxy corn, see section 4.21.
The tern "white kernels of corn with a slight tinge of light straw or pink color" includes kernels which are white and/or light straw or light pink in color and kernels which are white and pink in color provided the pink color covers less than 50 percent of the kernel. White and pink kernels in which the pink color covers 50 percent or more of the kernel arc considered "Corn of Other Colors." (Reference: Interpretive Line Slide Nos. OF-7.0, 7.1, 7.6, and 7.7.)
C. MIXED CORN. CORN THAT DOES NOT MEET THE COLOR REQUIREMENTS FOR EITHER OF THE CLASSES YELLOW CORN OR WHITE CORN AND INCLUDES WHITE-CAPPED YELLOW CORN.
(Reference: Interpretive Line Slide No. OF-7.2.)
Basis of Determination. Determine the class of corn by the color characteristics of the kernels. When an analysis for class is necessary, use a portion of approximately 250 grams of BCFM-frce corn.
Certification. Record the percentage of corn of other colors on the work record and certificate to the nearest tenth percent. When certificating Mixed corn, record the percentage of the mixture, in the order of predominance, in the "Remarks" section to the nearest tenth percent.
4.17 DAMAGED KERNELS. KERNELS AND PIECES OF CORN KERNELS THAT DAMAGED ARE BADLY GROUND-DAMAGED. BADLY WEATHER-DAMAGED, KERNELS DISEASED, FROST-DAMAGED, GERM-DAMAGED, HEAT-DAMAGED, INSECT-BORED, MOLD-DAMAGED, SPROUT-DAMAGED. OR OTHERWISE MATERIALLY DAMAGED.
Basis of Determination. Determine the amount of damaged kernels on a portion of approximately 250 grams of BCFM-frce corn.
TYPES OF CORN DAMAGE.
In general, a kernel of corn is considered damaged for inspection and grading purposes only when the damage is distinctly apparent and of such character as to be recognized as damaged for commercial purposes.
Blue-eve Mold. A germ infected with blue-eye mold, regardless of amount. If the mold is distinct, it is not necessary to open or scrape the kernel. Otherwise, lift the gem cover carefully to avoid destroying the evidence of Bold. (Reference: Interpretive Line Slide No. C-1.0.)
Do not confuse purple plumule with blue-eye mold. Purple plumule is not damage but is a genetic or varietal characteristic. (Reference: Interpretive Line Slide No.
Cob Rot. Cob rot is caused by a fungus that attacks weakened plants. It is detected by the presence of a distinct discoloration or rotting. Opening the kernel is not required to detect cob rot but may be necessary to determine the extent of other types of damage.
(Reference: Interpretive Line Slide No. C-2.0.)
Drier-Damaged Kernels. Kernels and pieces of kernels which have a discolored, wrinkled, and blistered appearance; or which are puffed or swollen and slightly discolored and which often have damaged germs; or whose seed coats are peeling off or have already peeled off; or which have a fractured or checked appearance resulting from external heat caused by artificial drying methods. Do not confuse drier damage with heat damage (drier). (Reference: Interpretive Line Slide No. C-3.0.)
Germ-Damaged Kernels fslight discoloration bv respiration). Kernels and pieces of kernels damaged by respiration or heat but not materially discolored. (Reference: Interpretive Line Slide No. C-4.0.) In most cases, the germ covering will have to be removed, exposing the area around the plumule. The discoloration must extend into the meat of the germ to be considered damaged.
Heat-Damaged Kernels. Kernels and pieces of kernels which are materially discolored by excessive respiration, with the dark discoloration extending out of the germ through
the sides and into the back of the kernel. (Reference: Interpretive Line Slide No. C-5.1 for Heat-damaged white corn and 5.2 for Heat-damaged Yellow corn.) Do not scrape
the sides of the kernels to make this determination for heat damage.
Heat.Damaged Kernels (drier). Kernels and pieces of kernels which are puffed or swollen and materially discolored by external heat caused by artificial drying methods. (Reference: Interpretive Line Slide No. C-5.0.)
Insect-Bored Kernels. Kernels and pieces of kernels with obvious insect-bored holes or which have tunneling, insect webbing, or insect refuse. Do not consider kernels partially eaten but entirely free from refuse, webbing, insects, or other forms of damage as damaged. (Reference: Interpretive Line Slide No. C-6.0.) Do not cut open the
kernel when making this determination. If the determination for insect-bored damage cannot be made without cutting the kernel, the kernel is considered
Mold-Damaged Kernels. Kernels and pieces of kernels infected with mold on exposed endosperm. Uhen a kernel of corn has been broken exposing the starch, it becomes
susceptible to mold. Check broken pieces carefully for mold. (Reference: Interpretive Line Slide No. C-7.0.) Do not confuse kernels that have dirt on them with kernels containing mold. Hold is usually blue or green in color. (Reference: Interpretive Line Slide No. C-7.1.)
Mold-like Substance. Whole kernels of corn which are 50 percent or more covered and pieces of kernels which are discolored and covered with a Bold-like substance.
Silk-Cut Kernels. Kernels and pieces of kernels with mold in silk cues. Kernels with clean silk cuts and are otherwise sound are not considered as being damaged.
(Reference: Interpretive Line Slide No. C-8.0.)
Surface Mold (blight). Kernels and pieces of kernels which have mold Id caused by corn leaf blight on them which appears to be only on the surface but actually penetrates
the seed coats. (Reference: Interpretive Line Slide No. C-10.0.)
Surface Mold. Kernels and pieces of kernels which contain surface Bold In any area or coabinatlon of areas equal to or greater than shown on the interpretive line slide.
(Reference: Interpretive Line Slide No. C-11.0)
Mold (pink Epicoccum). Kernels and pieces of kernels with germs infected with mold. (Reference: Interpretive Line Slide No. C-7.2.)
Sprout-Damaged Kernels. Sprouted kernels or those showing
evidence of a sprout. (Reference: Interpretive Line Slide
Certification. Record the percent of damaged kernels on
the work record and the certificate to the nearest tenth
4.18 HEAT-DAMAGED KERNELS. KERNELS AND PIECES OF CORN KERNELS
THAT ARE MATERIALLY DISCOLORED AND DAMAGED BY HEAT.
Basis of Determination. Determine heat-damaged kernels on a portion of approximately 250 grams of BCFM-free corn. (Reference: Interpretive Line Slide Nos. C-5.0,
5.1, and 5.2.)
Certification. Record the percent of heat'damaged kernels on the work record and the certificate to the nearest tench percent.
4.19 FLINT CORN AND FLINT AND DENT CORK
CORN THAT CONSISTS OF 95 PERCENT OR MORE OF FLINT CORN.FLINT CORN.
FLINT AND DENT CORN. CORN THAT CONSISTS OF A MIXTURE OF
FLINT AND DENT CORN CONTAINING MORE THAN 5.0 PERCENT BUT
LESS THAN 95 PERCENT OF FLINT CORN.
A kernel of Flint corn normally has a rounded crown and is usually smaller than a dent kernel.
A kernel of Dent corn is normally characterized by a distinct depression or dent in the crown of the kernel.
In mixtures of Flint and Dent corn, there is frequently a difference in the color of the two types. The shape of the kernel, the size, the texture, and the color characteristics are used in making a determination in mixtures of Flint and Dent corn.
Basis of Determination. Determine the special grades Flint and Flint and Dent on the characteristics of the kernels in the sample, when an analysis is necessary, use
a portion of approximately 250 grams of BCFM-frce corn.
Certification. When applicable, record the words "Flint" or "Flint and Dent" on the work record and the certificate in accordance with Section 4.2, Grade Designations.
4.20 CORN THAT CONSISTS OF 95 PERCENT OR MORE WAXY CORN,
WAXY CORN ACCORDING TO PROCEDURES PRESCRIBED IN FGIS INSTRUCTIONS.
Basis of Determination. When corn appears to contain 95 percent or more waxy kernels, test the sample to determine whether the special grade Waxy applies. Use exactly 100 kernels cut out of a portion of approximately 35 grans of BCFM-free corn.
When determining class for a sample of corn designated Waxy, apply the following guidelines:
For the special grade Waxy, the requirement of white kernels of corn with a slight tinge of light straw is not applicable; however, kernels which are "slightly yellow" are considered as corn of other colors. All other color requirements remain in effect for all classes of Waxy corn. (Reference: Interpretive Line Slide No. OF-7.8.)
Procedure for Testing Waxv Kernels of Corn. For required materials and equipment, see chapter 1, section 1.17. A. Pour 30 ml of the iodine stock solution into a spray
bottle and dilute it with 30 ml of distilled water.
B. Cut each of the whole kernels lengthwise (tip to crown) or across the cop exposing the starch in the endosperm. Place one-half of each kernel into a petri dish and discard the other half.
C. Carefully spray (do not soak) all the cut kernels with the iodine solution.
Wear safety equipment. Spray iodine solution only in a well ventilated area or within the working area of a laboratory hood. To prevent staining tables and surrounding areas, place the petri dish on a covered surface before spraying.
D. Approximately 1 to 3 minutes after spraying, the starch of the Waxy corn kernels will turn a red or reddish-brown color. The starch of nonwaxy kernels will turn a blue or violet color. Consider samples with 95 kernels (95%) turning red or reddish-brown color as Waxy corn. (Reference: Interpretive Line Slide Nos. OF-7.9 and 7.91.)
Certification. When applicable, record the word "Waxy" on the work record and the certificate in accordance with Section 6.2, Grade Designations.
4.21 After each determination, record the appropriate ASSIGNMENT results on the work record. After completing the OF GRADE analysis, compare these results with the limits for each grade factor specified in the grade cable in section 4.1. Following the guidelines in section 4.2, enter the grade in the appropriate space on the work record.