Defects
Post-harvest defects & deterioration
Harvested produce is alive and it fails in characteristic ways — bruised, chilled, sprouted, rotted, or eaten. This section documents those failures, what conditions cause them, and — critically — why what you can see is not the same as what you know.
Appearance is a clue, not a diagnosis
Visual symptoms alone do not confirm a cause. Post-harvest disorders frequently resemble one another, and some hazards — mycotoxin contamination in particular — can be present without any visible sign. Confirmation requires appropriate laboratory testing and qualified advice.
This matters in both directions. Many disorders look alike: chilling injury, freezing injury, and simple senescence can present similarly; blue mould and grey mould are routinely confused; an insect exit hole and a mechanical puncture are not always distinguishable by eye. And some of the most consequential problems are invisible — a lot with no visible mould can still carry mycotoxins, and chilling injury often only appears once the produce is warmed again, long after the decision that caused it.
Every entry therefore carries an explicit statement of what visual inspection cannot establish, and what confirmation actually requires.
How defects are grouped
- Mechanical — impact, compression, abrasion during handling.
- Physiological — the produce’s own metabolism going wrong (chilling injury, sprouting, scald).
- Pathological — fungal and bacterial decay.
- Entomological — insect feeding and contamination.
- Chemical / handling — heat damage, taint, and process-induced faults.
See post-harvest operations for the processes that reduce these defects, and quality attributes for what is measured.
Defects A–Z
Each entry covers what the defect is, the conditions that cause it, the commodities affected, what it is confused with, the processes that reduce it, and the limits of visual diagnosis.
26 entries
- Post-harvest defect
Abrasion Injury
Abrasion injury is surface damage from friction — produce rubbing against equipment, packaging, grit, or other units — that scuffs or strips the skin rather than rupturing tissue beneath it; its consequences are water loss and infection entry, and it routinely accompanies and conceals bruising in the flesh below.
- Post-harvest defect
Blue Mould
Blue mould is a post-harvest rot caused by Penicillium species that enter through wounds and produce soft, watery decay bearing blue-green spore masses; some species associated with it can also produce mycotoxins, and neither the presence nor the absence of visible mould establishes whether a toxin is present.
- Post-harvest defect
Bruising
Bruising is sub-surface tissue damage caused by mechanical force without the skin necessarily breaking; it is frequently internal and invisible from outside, commonly darkens only some time after the event that caused it, and its appearance rarely reveals whether the force was an impact or a sustained load.
- Post-harvest defect
Chilling Injury
Chilling injury is physiological damage that develops in chilling-sensitive commodities held at temperatures above their freezing point but below the temperature they tolerate — a distinct mechanism from freezing injury, and one whose symptoms usually appear only after the produce is returned to warmer conditions.
- Post-harvest defect
Compression Damage
Compression damage is injury from sustained static load — the weight of an over-deep bin, an over-stacked pallet, or an over-tight pack carried over hours or weeks; it produces bruising that looks much like impact bruising, and the position of a unit in the stack is a suggestive but confounded clue to its cause.
- Post-harvest defect
Cracking
Cracking is fracture of tissue or kernel without full separation into pieces; much of it originates before harvest in growing conditions and is merely discovered afterwards, and in grain it is commonly created by drying stress and remains invisible until the kernel breaks at milling.
- Post-harvest defect
Crown Rot
Crown rot is a decay of the cut crown surface of banana hands, caused not by one pathogen but by a complex of several fungi acting together; the wound it infects is created deliberately by dehanding, it is largely invisible when the fruit is packed, and it develops during transit and ripening to become a leading cause of rejection on arrival.
- Post-harvest defect
Frass Contamination
Frass contamination is the accumulation of insect excreta, cast skins, webbing, body fragments, and associated dust in a stored commodity; it is simultaneously an indicator that an infestation occurred and a contaminant in its own right, but it dates nothing — frass persists long after the insects are gone, and cleaning removes it without removing the history it recorded.
- Post-harvest defect
Freezing Injury
Freezing injury is physical damage caused by ice forming inside harvested tissue and rupturing its cell structure; on thawing the affected tissue becomes translucent, water-soaked, and leaky. It is a fundamentally different event from chilling injury, which occurs above the freezing point with no ice involved.
- Post-harvest defect
Greening
Greening is the light-induced formation of chlorophyll in potato tubers, accompanied by an increase in glycoalkaloids through a separate but light-associated response; the green colour is an indicator that the tuber has been exposed to light, and not a measure of what has accumulated in it.
- Post-harvest defect
Grey Mould Rot
Grey mould rot is a post-harvest decay caused by Botrytis cinerea, which colonises wounds and senescing tissue, continues to develop at cold-storage temperatures, and spreads by contact between touching units; it frequently begins as a latent field infection, and it cannot be reliably told apart from blue mould by eye.
- Post-harvest defect
Heat Damage
Heat damage is thermal injury to grain and seed caused either by over-rapid or over-hot drying or by self-heating in store, expressed as darkening, scorching, and loss of germination and processing quality; its two most important effects — loss of viability and loss of processing quality — occur before any discolouration is visible, so a sound-looking lot can already be damaged.
- Post-harvest defect
Impact Damage
Impact damage is injury from a single dynamic blow — a drop, a throw, or a fall against a hard surface — delivered in an instant; it is an event rather than an appearance, and the tissue damage it leaves cannot be reliably distinguished from damage caused by sustained compression.
- Post-harvest defect
Insect Boring Damage
Insect boring damage is the tunnelling, hollowing, and holing of stored grain, pulses, and nuts by storage insects such as weevils, borers, and bruchids; much of it develops entirely inside the kernel and is invisible from outside, and a hole in a kernel identifies neither what made it nor whether the infestation is still alive.
- Post-harvest defect
Internal Browning
Internal browning is the discolouration of flesh or vascular tissue inside otherwise normal-looking produce. It is an umbrella presentation rather than a single disorder: chilling injury, controlled-atmosphere injury, senescence, degenerated water-core, and cultivar or mineral-nutrition disorders all produce it, and it is invisible from outside.
- Post-harvest defect
Off-Odour
Off-odour is any foreign, musty, sour, fermented, rancid, or chemical smell in a commodity; it is a sensory attribute rather than a measurement, it is a symptom shared by several unrelated causes including some that originate outside the lot entirely, and — because mycotoxins are odourless — a lot that smells perfectly sound may still carry one.
- Post-harvest defect
Pitting
Pitting is the appearance of small sunken depressions in the skin where groups of cells beneath have collapsed. It is a symptom name rather than a disorder: chilling injury, pathogens, physical handling, and controlled-atmosphere injury all produce it, and in tropical and subtropical produce chilling injury is much the most common cause.
- Post-harvest defect
Post-harvest Anthracnose
Post-harvest anthracnose is a Colletotrichum rot that infects fruit in the field while it is still immature, then stays dormant and completely invisible until the fruit ripens, when it erupts as sunken dark lesions; a lot can therefore be genuinely symptomless at packing and unsaleable on arrival, and no visual inspection at the packhouse can detect it.
- Post-harvest defect
Senescence
Senescence is the normal, programmed end of post-harvest life — not a failure, not a disease, and not something any process prevents; it is the baseline against which every other defect must be judged, and the disorder most often confused in both directions with the failures that merely resemble it.
- Post-harvest defect
Shrivel
Shrivel is the visible consequence of water loss from harvested produce — loss of turgor, wrinkling, softening, and dullness — and is simultaneously a quality defect and a direct loss of saleable weight, accumulating irreversibly across the whole chain rather than at any one point in it.
- Post-harvest defect
Sour Rot
Sour rot is a soft, watery, disintegrating decay caused chiefly by Geotrichum candidum, most familiar in citrus and tomato, distinguished by a sour fermented odour and by the absence of the dry powdery spore mass that the blue and green moulds produce; it enters through wounds and is both spread by and attractive to fruit flies.
- Post-harvest defect
Splitting
Splitting is tensile failure that opens a unit or separates it into pieces; the line between a split and a crack is largely a matter of commodity convention and grade-standard wording rather than mechanism, and much splitting — in citrus, cabbage, grapes, and onions — happens on the plant before harvest.
- Post-harvest defect
Sprouting
Sprouting is the resumption of growth in a stored tuber or bulb once its natural dormancy has ended — a developmental transition whose timing is cultivar-dependent and modulated, but not created, by storage conditions.
- Post-harvest defect
Storage Rot
Storage rot is a collective term for the microbial breakdown of stored grain and produce by a large number of unrelated fungi and bacteria; it names an outcome rather than an organism, the responsible agent cannot be read from the rot itself, and neither the presence nor the absence of visible decay settles whether a mycotoxin is present.
- Post-harvest defect
Superficial Scald
Superficial scald is a storage disorder of apples and pears in which the skin develops diffuse, irregular browning while the flesh beneath usually remains sound. It appears only after an extended period in store, which means it cannot be detected when the fruit goes in.
- Post-harvest defect
Water-Core
Water-core is an apple disorder in which regions of the flesh become water-soaked, glassy, and translucent, associated with sorbitol accumulating in the spaces between cells. It arises before or at harvest rather than from handling, is invisible from outside, and may either dissipate in storage or degenerate into internal browning — which is why markets grade it very differently.
Sources
This article draws on the following authoritative sources. See our sources & methodology for how they are selected.
- [1]USDA ARS — Agricultural Research Service (opens in a new tab)Authoritative
USDA Agricultural Research Service (ARS)
Cited for: Post-harvest disorders and storage research
- Type:
- Government agency
- Jurisdiction:
- United States
- Accessed:
- 2026-07-12
- [2]FAO — Food and Agriculture Organization (opens in a new tab)Authoritative
Food and Agriculture Organization of the United Nations (FAO)
Cited for: Post-harvest deterioration and loss
- Type:
- Intergovernmental organization
- Jurisdiction:
- Global
- Accessed:
- 2026-07-12
- Authoritative
Cited for: Mycotoxin and food-safety context
- Type:
- Government agency
- Jurisdiction:
- European Union
- Accessed:
- 2026-07-12