Internal Quality

A commodity that scores well against every external grading criterion — colour, size, shape, absence of surface blemish — can still be unsaleable once cut open. That decoupling between external appearance and internal condition is the entire reason internal quality is tracked as a category of its own: it names a class of failure that a purely visual, exterior-only grading line cannot catch, and it explains why internal disorders so often surface only after a lot has cleared inspection, been shipped, and been paid for.

Internal quality is assessed by cut-sample examination: a subset of units is cut open and the exposed tissue is examined against a defined scoring scheme for the disorders relevant to that commodity. This method is destructive on every unit it is applied to, which means the result is necessarily an inference about the whole lot drawn from a small number of sacrificed units — it is not, and should never be read as, a claim that internal condition can be seen from outside without cutting.

Internal disorders are often heterogeneous in their distribution through a lot, clustering by orchard block, canopy position within a tree, or location within a store rather than occurring uniformly. A cut-sample estimate therefore carries real sampling uncertainty, and a small sample can easily miss a low-incidence disorder that is nonetheless large enough, once the whole lot is considered, to generate complaints from buyers.

Non-destructive alternatives do exist — near-infrared transmission, X-ray imaging, and acoustic testing among them — and each can detect certain internal disorders without cutting the unit open. But each depends on a specific calibration or physical contrast mechanism that only picks up what it was built to detect, and none of them functions as a general-purpose internal-quality instrument capable of catching every disorder that a cut sample would reveal.

• Pre-harvest mineral nutrition — calcium status in particular underlies several storage disorders.
• Maturity at harvest — see Maturity Index.
• Chilling exposure — see Chilling Sensitivity.
• Storage duration.
• Storage atmosphere — including carbon dioxide injury that can arise in controlled-atmosphere storage.

• Not external quality or grade — a flawless exterior does not certify internal condition.
• Not a food-safety verdict — internal disorders are physiological, and some genuine safety hazards leave no internal sign at all.
• Not a single measurable property — it is an umbrella over disorders with different causes that a single score flattens.
• Not diagnostic of cause — several disorders look alike on a cut face, and confirming which one is present usually requires the lot’s history and often laboratory work.