U.S. Government Inspection and Grading
Purpose
Global corn supply chains need verifable, predictable and consistent oversight measures that fit the diverse needs of all end users. Oversight measures, implemented through standardized inspection procedures and grading standards, are established to provide:
- Information for buyers about grain quality prior to arrival at destination, and
- Food and feed safety protection for the end users.
The U.S. is recognized globally as having a combination of official and industry standards that are typically used for exporting grains and referenced in export contracts. U.S. corn sold by grade and shipped by vessel in foreign commerce must be officially inspected and weighed by the USDA’s Federal Grain Inspection Service (FGIS) with a few exceptions. Qualified state and private inspection agencies are permitted to be designated by FGIS as official agents to inspect and weigh corn at specified interior locations. In addition, certain state inspection agencies can be delegated by FGIS to inspect and weigh grain officially at certain export facilities. Supervision of these agencies’ operations and methodologies is performed by FGIS’s field office personnel.
Inspection and Sampling
The loading export elevator provides FGIS or the delegated state inspection agency a load order specifying the contract quality of the corn to be loaded as designated in the export contract. The load order specifies the contract U.S. grade requirements of corn which have been agreed upon by the foreign buyer and the U.S. supplier, plus any special requirements requested by the buyer such as minimum protein content, maximum moisture content, or other special requirements. The official inspection personnel determine and certify that the corn loaded in the vessel actually meets the requirements of the load order. Independent laboratories can be or are used to test for quality factors not mandated to be performed by FGIS or for which FGIS does not have the local ability to test.
Shipments or “lots” of corn are divided into “sublots.” Representative samples for grading are obtained from these sublots using a diverter sampling device approved by FGIS. This device takes an incremental portion every 500 bushels (about 12.7 MT) from the moving grain stream during assembly for final shipment. The incremental portions are combined by sublot and evaluated by licensed inspectors. The results are entered into a log and, using statistical techniques, a determination is made as to acceptance or rejection on each factor according to specifications in the contract. Any sublot that does not meet requirements on any factor must be returned to the elevator or given a separate certification. The average of all sublots meeting the contract requirements for each factor tested is reported on the final certificate.
Grading
Yellow corn is divided into five U.S. numerical grades and U.S. Sample Grade. Each grade has limits for test weight, broken corn and foreign material (BCFM), total damaged kernels, and heat-damaged kernels as a subset of total damage. The limits for each grade are summarized in the table shown in the “Grade Requirements and Conversions” section on page 36. In addition, FGIS provides certification of moisture and other attributes, if requested, such as stress cracks, protein, oil and mycotoxins. In some cases, independent labs are used to conduct the non-official FGIS tests, depending on the contract.
Export contracts for corn specify many conditions related to the cargo, including the contract grade. Since the limits on all grade factors cannot always be met exactly simultaneously, some grade factors may be better than a particular grade, but they cannot be worse. For example, test weight may be higher than U.S. No. 1 on nearly all sublots. To allow for this flexibility, contracts are often written as “U.S. No. 2 or better” or “U.S. No. 3 or better”. This permits some factors to be near the limit for that grade while other factors may be better than called for in the grade specifications.