How to keep plums fresh when you can't eat them all? Store them this way and they'll last a long time
Every year during plum harvest season, it is a race against time for fruit growers. Because plum yields are high, if a large volume hits the market without being controlled, there is a risk of a market glut, and the losses can be considerable. But plums are also a fruit that ripens and rots extremely easily. So what should you do if you can't eat them all? Is there any way to make plums keep longer?
I. Harvesting Plums
Before keeping plums fresh, you also need to pay attention to the harvesting process. If harvested too early, the fruit tastes poor; if left too late, the fruit has already softened and lost its economic value. So the ideal harvest time is when the skin of green-skinned plum varieties turns yellow-green; for plums with purple, red, or black skin, harvest when the skin has fully colored but the flesh is still fairly firm. When harvesting, choose a cool morning or an evening after the fruit temperature has dropped, wear gloves, and pinch the fruit stalk with your fingers to pick the fruit from the branch. Do not touch the fruit body directly, so as not to rub off the waxy layer on the fruit, which would affect its appearance and storage results.
II. Methods for Keeping Plums Fresh
1. Cold storage: choose a cold storage facility with a refrigeration temperature of 0°C-1°C, a relative humidity of 85%-90%, and good ventilation.
2. Ice pit storage: spread crushed ice evenly over the bottom of the pit, then place fruit baskets (baskets of this kind are better for such storage) on the ice surface and stack them. After stacking, spread another layer of ice, and continue stacking in this order. After stacking is complete, cover with a layer of plastic film, and on top of the film pile about 90 cm of sawdust or similar material for insulation and heat preservation. The overall temperature inside the pit should likewise be controlled at 0-1°C. This method requires the ice pit to be airtight and can keep the fruit fresh for a relatively long time. After winter, it can also be transferred to an ordinary pit for continued storage, until it is supplied to the market at Spring Festival.
3. Controlled atmosphere storage: remove the stems from plums harvested at the right time, discard diseased, insect-damaged, and bruised or rotting fruit, then seal the plums in polyethylene film bags 0.025 mm thick for storage. At a temperature of 0-1°C, a carbon dioxide content of 7-8%, and an oxygen content of 1-3%, plums can be stored for 2-3 months.
III. Precautions for Keeping Plums Fresh
1. Pre-cooling treatment: within 3 hours after harvesting plums, and at the latest within 24 hours, they must be cooled to below 4°C-5°C to prevent brown rot and soft rot. Pre-cooling method: place the fruit in a 0.5°C-1°C storage room for cooling.
2. Timely air extraction: after food has been stored in a cold storage warehouse for a period of time, gases such as carbon dioxide and ethylene tend to accumulate, so the cold storage warehouse needs an air extraction system to ensure the circulation of fresh air, which helps with the storage and freshness of the food.
3. Temperature control at all times: the temperature in a cold storage warehouse is affected by changes in the outside air temperature, so managers should adjust the warehouse temperature according to the actual conditions inside during inspections to ensure the stability of the cold storage temperature. At the same time, before the product leaves the warehouse, a gradual warming method should be used, so that because of the large temperature difference between inside and outside, water droplets do not condense on the surface of the fruit after it leaves the warehouse.