Avocados

The suppression of ripening on the tree is the commercial foundation of the avocado trade. A grower with mature fruit hanging is holding inventory that is not deteriorating on any short timescale and is not costing anything to refrigerate, and can pick to order across a long window. No apple or banana grower has that option.

The flexibility is not unlimited. Fruit held very long on the tree accumulates more oil, which is not automatically better — it can carry rancid or off flavours — and long-hung fruit tends to have a shorter life after picking and can interfere with the next season's flowering. Late-hung fruit also becomes more vulnerable to handling damage. So the window is wide, but it has ends.

Because an avocado does not change colour or soften on the tree, nothing visible reveals whether it is ready to pick. The industry's answer is dry matter: a sample of fruit is weighed, dried, and reweighed, and the resulting figure stands as a proxy for oil content. Fruit picked below the accepted level for its cultivar and region will soften but never ripen properly — it stays rubbery, tastes watery, and never develops the buttery texture that defines the eating quality. This failure mode is exactly why minimum-maturity rules for avocados exist in law in several markets.

The minimum is set by cultivar, region, and jurisdiction, and it is not a single number. Commercial practice frequently picks above the legal floor, because the floor represents the point of acceptability rather than of good eating. Maturity assessment is done on sampled fruit before the block is harvested, and it is the one measurement that decides whether the lot has a future.

Once picked, avocados are cooled quickly and shipped cold — but, being chilling-sensitive, only within their tolerance, below which the flesh develops grey-brown discolouration and vascular browning that appears when the fruit is finally cut. The tolerance is not fixed: it varies with cultivar and with fruit maturity, so the same regime can be safe for one lot and injurious for another. Long sea voyages commonly use controlled atmosphere, lowering oxygen and raising carbon dioxide to slow the climacteric further and stretch the fruit's transportable life.

At destination the fruit is ripened deliberately in rooms with warmth and ethylene, exactly as bananas are, to deliver ready-to-eat fruit on a scheduled day. Ripe avocados bruise very easily, which is the trade's central tension: consumers want fruit ready to eat, and fruit that is ready to eat is fruit that can barely be handled. Firmness sorting on packing lines is used to segregate fruit by how far along the ripening curve it has travelled.

Avocados are specified on size and count, skin condition, firmness stage, and freedom from external and internal defects. Internal condition is the buyer's real concern and the hardest thing to see: flesh browning, vascular discolouration, and rots inside an intact-looking fruit are the complaints that generate claims, and they usually originate in temperature abuse or over-maturity earlier in the chain.

• Chilling injury — grey-brown flesh and vascular browning revealed only when cut
• Anthracnose and stem-end rot — latent infections expressing during ripening
• Bruising — the dominant damage in ripe fruit, inflicted by ordinary handling
• Immature fruit that shrivels or softens without ripening properly
• Uneven ripening across a room or pallet
• Skin blemish, lenticel damage, and wind rub from the orchard

Avocados are overwhelmingly sold and eaten as whole fresh fruit. Because the flesh browns quickly once exposed, processing has developed around technologies that manage that — chilled and high-pressure-treated pulp and guacamole preparations, and frozen product — which take fruit that is sound but off-specification for size or appearance. Avocado oil, pressed from the flesh rather than the seed, is a smaller outlet that also draws on fruit outside the fresh grade.

• Food — whole fresh fruit, the dominant use
• Food processing — pulp, guacamole, and frozen product from off-grade fruit
• Oil — avocado oil pressed from the flesh, for food and cosmetic use