Kiwifruit is picked firm and ripens in store, so harvest maturity has to be measured. The UNECE kiwifruit standard (FFV-46) asks for at least 6.2 °Brix or an average dry matter of 15 per cent at packing and expects 9.5 °Brix when the fruit enters the distribution chain. In New Zealand export practice the average of a 10-fruit sample must be at least 6.2, and if two of the ten fall below 5.8 the orchard is not accepted for picking.
In store. Well-handled Hayward-type kiwifruit keeps 4 to 5 months at 0 °C and 90 to 95 per cent humidity, and about 6 months in controlled atmosphere (1 to 2 per cent oxygen, 3 to 5 per cent carbon dioxide). After harvest it is cooled to near 0 °C as soon as practicable, preferably by forced air. As little as 5 to 10 ppb ethylene accelerates softening, so kiwifruit is not held in the same room as ethylene producers such as apples.
Leaving the store
Temperature swings speed up softening: in the Xuxiang cultivar, 3 days of alternation between 2 and 5 °C or between 2 and 7 °C gave more softening than a constant 2 °C. Moving the fruit from store door to vehicle in a closed, insulated container shortens that exposure. Keep the readings and the store-entry conditions with the same lot.
