Bananas

Bananas cannot be shipped ripe — a ripe banana would not survive a fortnight at sea, and its texture would not survive the handling. The trade therefore harvests fruit that has reached full physiological maturity but has not begun to ripen, and then works to keep it in that suspended state. Harvest maturity is judged by the fullness of the finger — how round it has become in cross-section, sometimes called grade or calibre — rather than by colour, because a mature-green banana and an immature one look much the same.

Bunches are cut from the plant, then dehanded and cut into clusters, washed to remove latex from the cut crowns, and packed into cartons, usually within hours and usually on the plantation itself. The crown cut is the fruit's main wound and the main entry point for the crown rots that dog the trade, so its treatment and hygiene get disproportionate attention.

Two controls hold ripening off. The first is temperature: the fruit is cooled soon after packing and shipped refrigerated, which slows respiration and extends green life. The second is atmosphere: ethylene must be kept away from the fruit, because bananas respond to traces of it. Ripening fruit, damaged fruit, and other produce are all ethylene sources, which is why mixed loads are a hazard and why ventilation and controlled or modified atmospheres are used on long voyages to hold down oxygen and vent the ethylene the fruit itself emits.

The temperature control is bounded from below. Bananas are chilling-sensitive, and holding them below their tolerance causes chilling injury — a dull, greyish skin, failure to ripen properly, and hard core — that only becomes visible later and cannot be undone. The shipping temperature is therefore a narrow compromise: cold enough to suspend ripening, never cold enough to injure. This is precisely the opposite of the apple case, where near-freezing storage is routine.

At the destination the process is reversed on purpose. Cartons go into sealed ripening rooms where the fruit is warmed and dosed with ethylene, which triggers the climacteric. Starch converts to sugar, the peel degreens, the flesh softens, and the fruit passes through the colour stages the trade uses as a common language for how far along a pallet is. Because the fruit then produces its own ethylene, the room must be ventilated and its temperature managed as the fruit generates its own heat.

Ripening is scheduled, not merely permitted. A ripener is asked to deliver fruit at a specified colour stage on a specified day, and the room conditions are set to hit that target. This makes bananas one of the clearest illustrations of the difference between a crop and a commodity: the eating quality is manufactured downstream, on a timetable, thousands of kilometres from where the fruit grew.

Fresh-market bananas are specified on finger length and calibre, cluster size and presentation, peel cleanliness, and freedom from injury and decay. Because the peel bruises and scars easily and every mark is visible on a pale yellow surface, mechanical damage is the leading downgrade — and much of it is inflicted long before the fruit is ripe, then revealed when the peel degreens.

• Crown rot — decay entering at the cut crown, the trade's characteristic post-harvest disease
• Chilling injury — dull peel, poor ripening, and hard core from cold below tolerance
• Bruising, scarring, and neck injury from handling
• Premature ripening in transit — usually traced to heat, delay, or an ethylene source
• Latex staining from the crown cut
• Uneven ripening across a pallet or room

The internationally traded banana is a dessert fruit eaten fresh. Cooking bananas and plantains, which are handled and consumed quite differently, are a separate matter and are not what moves through the mature-green export chain. Fruit rejected at packing — off-calibre, scarred, or otherwise unfit for the carton — stays in the producing country and is eaten locally, dried, or fed to livestock rather than exported.

• Food — fresh dessert fruit, the dominant use of exported bananas
• Food processing — purée, dried fruit, and flour from off-grade fruit, largely at origin
• Feed — rejected fruit and plantation residues used locally