How to store plums

In the brief guide, we are going to answer the question ‘How to store plums’ with an in-depth analysis of what is the shelf life of plums, what you should keep in mind when storing them and if plums spoil.

How to store plums?

Plums should be stored at 0 °C (32 °F) with 90 to 95% relative humidity. Although passive cooling of plums is possible, forced air and hydro-cooling are more efficient. Some cultivars’ ground color and flesh firmness are preserved during controlled environment preservation (1,2).

If plums are under-ripe when you get them home, store them in a paper bag at room temperature for 2-3 days. This will aid in the ripening process. Keep them in a plastic bag in the crisper drawer for up to 5 days if they’re ripe.

Fresh-cut plums are best kept at 0 °C (32 °F) in packages that minimize water loss (2).

Remember that plums are prone to chilling injury (translucency, internal browning, mealiness, bleeding, inability to mature, and taste loss) (1). 

These symptoms occur faster and more severely at 5 °C (41 °F)  than at 0 °C (32 °F), as with peaches and nectarines. After removing the fruit from cold storage and exposing it to room temperature, the symptoms worsen (2).

What is the shelf life of plums?

Plum is a perishable fruit with a very short shelf life of 3-4 days. Ripe plums are generally more perishable and have a shorter shelf life compared to unripe ones (3). 

On average, properly stored plums can last for about 3 to 5 days at room temperature. However, refrigeration can significantly extend their shelf life. When stored in the refrigerator, plums can typically stay fresh for up to 1 to 2 weeks (4).

Marketing life of fresh-cut plums ranges from 2 to 5 days, depending on cultivar and stage of ripeness (firmness) at the time of slicing (2).

What affects the shelf life of plums?

Plums’ shelf life is affected by a variety of factors, including physiological traits and environmental circumstances.

Plums are climacteric fruits with a high respiration rate, which means they keep getting ripe even after being harvested and their shelf life is influenced by the degree of ripeness at the time of purchase, riper plums often have a shorter shelf life than unripe ones (4). 

Plums are also susceptible to ethylene gas, temperature, and humidity. Higher temperatures hasten ripening and spoiling, whereas lower temperatures halt the ripening process and lengthen shelf life (4) 

Humidity levels should be kept under control to avoid excessive moisture loss or mold growth such as gray mold caused by Botrytis cinerea (5). 

When it comes to plum’s ripeness, ethylene gas, a naturally occurring plant hormone, can promote ripening and should be controlled to avoid premature softening and degeneration. Store plums away from producing-ethylene fruits like banana, apple and others (6).

What steps should you keep in mind when storing plums?

Good plums can be purchased or picked

Plums with no flaws, discoloration, or soft patches are the best. You may ripen plums at home; the most essential thing is to select plums from a nice batch; it’s fine if they’re still a little firm (4).

In a paper bag, place the unripe plums

If your plums do not yet smell aromatic or feel slightly soft to the touch, they should be allowed to ripen for a few days outside the refrigerator. Ethylene is released as plums and other fruits ripen. Placing them in a paper bag together envelopes the plums with this gas, causing them to ripen faster (1,2).

Unripe plums should not be stored in the refrigerator. In the chilly temperature, they won’t be able to continue ripening, and you’ll end up with bland, mealy plums (7).

Instead of putting the plums in a paper bag, you can put them in a bowl on the counter if you aren’t in a hurry for them to ripen. It will take an extra day or two for them to ripen.

Allow the plums to mature in the refrigerator

Keep them at a temperature to ripen. Wait until they’re fully ripe before storing them at a colder temperature (4).

Make sure the plums don’t get too hot; putting them in a sunny window could cause them to overheat and rot faster.

Check the maturity of the plums

If this is the case, the plums are ripe and ready to eat or store for a longer period of time.  As the skin of the plum ripens, it takes on a dusty appearance. 

Catch the plums before they become too soft or the liquid starts to leak from the skin; this indicates that they are overripe (2).

Refrigerate plums that are ripe

This will keep them in good shape and keep them from deteriorating quickly. Place them in an open plastic bag, not one that has been sealed. Plums can be kept in the refrigerator for two to four weeks (2,4). 

Check to see if your refrigerator is clean and odor-free. After a few days, plums take on the odor of the refrigerator. Place them in the refrigerator’s crisper area.

Eat plums as soon as possible after picking or purchasing them

Although plums can be stored for several weeks, they are best eaten when they are still fresh. It’s best if you can consume them as soon as they’ve ripened. Try one of these delectable meals if you have a large bunch of plums to use up:

Plums should be frozen

Plums can be frozen for several months or even a year. Choose plums that are at their ripest and most flavorful; under ripe plums will not taste well when thawed (8).

The plums should be washed under running water and dried with a paper towel. Remove the pits from the plums and slice them into wedges. On a cookie sheet, arrange the wedges. The plum wedges should be frozen. Fill a food storage bag or bucket halfway with frozen wedges. Put the date on the food storage bag or container and put it back in the freezer (8,9).

Make jam with the plums

This is a wonderful method for preserving plums so that they last for months. Before blending the flesh with sugar, pectin, and lemon juice, you’ll need to peel your plums to remove the skins. Use sanitized jars to store your jam and enjoy it throughout the winter (8).

Do plums spoil?

Yes, plums can spoil over time. Since plums are perishable fruits, they are susceptible to microbial growth, primarily from bacteria and fungi. 

As we mentioned before, moisture content, temperature, and storage conditions play crucial roles in determining the shelf life of plums, and storing plums improperly can create a favorable environment for bacteria like Curtobacterium and Pseudomonas species and mold growth such as Botrytis cinerea (5,10).

Changes in color, texture, and odor are all indicators of spoiled plums. Plums that have spoiled may acquire black or soft areas, become mushy or wrinkled, and exude a foul or fermented odor. Mold development on the surface is another sign of rotting (11). 

Eating spoiled plums can be risky for health. Moldy plums may contain mycotoxins, harmful substances produced by molds that can cause allergies and other adverse effects. Additionally, the bacteria and fungi present on rotten plums can lead to foodborne illnesses, resulting in symptoms like nausea, vomiting, diarrhea, abdominal discomfort, and fever (12,13).

Conclusion

In the brief guide, we discussed answering the question ‘How to store plums’ with an in-depth analysis of what is the shelf life of plums, what you should keep in mind when storing them and if plums spoil.

References 

1. Watkins, C.B., Nock, J.F. Production Guide for Storage of Organic Fruits and Vegetables. NYS IPM, 2012.

2. The Commercial Storage of Fruits, Vegetables, and Florist and Nursery Stocks. Agricultural Research Service Agriculture, Handbook Number 66, 2016.

3. Kumar, P., et al. Edible coatings influence the cold-storage life and quality of ‘Santa Rosa’ plum (Prunus salicina Lindell). J Food Sci Technol. 2018;55(6):2344-2350.

4. Álvarez-Herrera, J.G. Effect of Storage Temperature and Maturity Stage on the Postharvest Period of ‘Horvin’ Plums (Prunus domestica L.). Ing. Investig., 2021, 41.

5. Ferrada, E.E., et al. Identification and Characterization of Botrytis Blossom Blight of Japanese Plums Caused by Botrytis cinerea and B. prunorum sp. nov. in Chile. Phytopathology. 2016 Feb;106(2):155-65.

6. Farcuh, M. Ethylene regulation of sugar metabolism in climacteric and non-climacteric plums. Postharvest Biology and Technology, 2018, 139, 20-30.

7. Manganaris, G.A., et al. Cell wall modifications in chilling-injured plum fruit (Prunus salicina). Postharvest Biology and Technology, 2008, 48, 77-83.

8. Silva, C.L.M. Home Freezing of Fruits and Vegetables. In book: Frozen food science and technology, 2008.

9. Zander, A., Bunning, M. Guide to Washing Fresh Produce. Colorado State University, 2010.

10. Janisiewicz, W., et al. Culturable bacteria from plum fruit surfaces and their potential for controlling brown rot after harvest. Postharvest Biology and Technology, 76:145–151

11. Kanupuru, P., Uma Reddy, N.V. A Deep Learning Approach to Detect the Spoiled Fruits. WSEAS Transactions on Computer Research, 2022, 10:74-87.

12. Brand, A.D.V., Bulder, A.S. An overview of mycotoxins relevant for the food and feed supply chain: using a novel literature screening method. RIVM letter report , 2019, 0223.

13. What You Need to Know about Foodborne Illnesses. FDA, 2022.