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Post-Harvest · Post-harvest operation

Sorting and Grading

Also known as: Grading, Sorting, Quality classification

Sorting and grading separate produce and grain by quality attributes such as size, colour, shape, and defects into consistent grades, removing unsound units and matching each lot to its market, price, and end use.

Dated referenceLast reviewed: 2026-07-13Updated: 2026-07-13
Illustrative diagram · AgricultureID (original)

Sorting and grading classify harvested produce by quality. Sorting usually means separating out unwanted units — those that are diseased, damaged, misshapen, or the wrong ripeness — while grading arranges the sound produce into classes defined by attributes such as size, colour, shape, and freedom from defects. Together they convert a mixed harvest into consistent lots that can be priced, packed, and sold to a defined standard.

These steps add value in several ways. Removing decayed or damaged units early prevents them from spoiling sound produce during storage and transport. Uniform grades command better and more predictable prices, meet buyer and regulatory specifications, and let each lot be directed to the market or process it suits best. Sorting and grading range from careful hand selection to automated lines using sizing and optical technology.

Why sorting and grading matter

A single decayed or damaged unit can spread rot to its neighbours and shed ethylene and moisture, so removing unsound produce before storage and packing protects the rest of the lot. Beyond loss prevention, grading creates the uniformity that markets reward: buyers can specify and pay for a known class, retailers can display consistent produce, and processors receive material suited to their line.

Grading also allows produce of different quality to be directed appropriately — premium grades to fresh markets, sound but less uniform produce to processing, and unmarketable material to other uses — which raises the overall value recovered from a harvest.

Attributes and methods

Size and weight
Produce is separated by dimension or weight using screens, diverging rollers, or weight sizers to meet size grades.
Colour and appearance
Colour, ripeness, and surface appearance are judged by eye or by optical and camera-based sorters.
Defects and soundness
Damaged, diseased, misshapen, or foreign units are removed by inspection or automated detection.

Grain is similarly graded on attributes such as moisture, foreign matter, broken and damaged kernels, and test weight, which together determine its grade and price. The attributes that matter, and the standards applied, depend on the commodity and its market.

Good practice

  • Sort out decayed and damaged units early to protect sound produce.
  • Grade to recognised standards and buyer specifications for consistency.
  • Handle produce gently during sorting to avoid adding bruises and cuts.
  • Direct each grade to the market or process for which it is best suited.

Relationships

Evidence-backed connections in the knowledge graph.

Related topics

Scope & limitations

Geographic scope: Global. Grade definitions and standards vary by commodity, market, and country.

  • Grade definitions and quality standards are commodity- and market-specific and differ between countries and buyers.
  • Sorting and grading classify existing quality; they cannot improve immature, damaged, or diseased produce.
  • Automated sorting can miss internal defects not visible on the surface, so some quality issues remain hard to detect.

Sources

This article draws on the following authoritative sources. See our sources & methodology for how they are selected.

  1. [1]FAO — Food and Agriculture Organization (opens in a new tab)

    Food and Agriculture Organization of the United Nations (FAO)

    Authoritative

    Cited for: Sorting and grading in post-harvest handling of produce

    Type:
    Intergovernmental organization
    Jurisdiction:
    Global
    Accessed:
    2026-07-12
  2. [2]USDA — U.S. Department of Agriculture (opens in a new tab)

    United States Department of Agriculture (USDA)

    Authoritative

    Cited for: Quality grades and standards for fruits, vegetables, and grain

    Type:
    Government agency
    Jurisdiction:
    United States
    Accessed:
    2026-07-12
  3. [3]USDA ARS — Agricultural Research Service (opens in a new tab)

    USDA Agricultural Research Service (ARS)

    Authoritative

    Cited for: Sorting technology and quality assessment research

    Type:
    Government agency
    Jurisdiction:
    United States
    Accessed:
    2026-07-12

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