Handling after harvest
- Ideally plums should be picked and packed on the same day and cooled to -0.5 °C as soon as possible after packing.
- If plums will be packed on the harvest day a delay of 4 hours between harvest and packing is advised. Bins can be held in the shade in a draft or placed in a cold store at 12 to 15 °C.
- If plums will only be packed between 4 and 24 hours after harvest, bins should be kept at 12 to 15 °C. The main advantage in comparison to storing bins at -0.5 °C is a reduction in decay, slightly firmer fruit and less shrivel after cold storage.
- If a delay of more than 24 hours between harvest and packing is anticipated, bins must be placed at -0.5 °C. Ensure that there is adequate airflow through the bins to facilitate cooling.
- After packing, plums should be forced-air cooled to the target pulp temperature of -0.5 °C within 48 hours.
- While the target temperature after cooling is -0.5°C a temperature tolerance of up to 3°C in pulp temperature is allowed at loading.
- Care must be taken not to cool the plums to below 3 °C in less than 24 hours. This will have a negative effect on internal quality especially if the fruit was subjected to heat waves prior to harvesting.
- Packaging has a significant effect on cooling rate. It is therefore important to separate different packaging types, such as jumble packed plums and plums packed in standard 5 kg loose packed cartons, if possible, to avoid too fast cooling of the plums in the jumble packed cartons. Plums packed in punnets and thrift bags will also cool faster than plums packed in standard 5 kg cartons.
- Choose an appropriate temperature regime. For more information see the plum shipping regimes link, or cultivar specific information.
- The fresh air ventilation in integral containers is set a 15m3 per hour and in conventional decks the CO2 concentration are maintained below 0.5 %.
- It is recommended that void plugs are used in containers loaded with 20 pallets to block off the openings on the container floor at the door. This will improve cooling in the container.