How to know if watermelon is spoiled

In this article, we will briefly discuss how to know if watermelon is spoiled and will also talk about how to store watermelon and what happens if you consume spoiled watermelon. . 

How to know if watermelon is spoiled?

To know if watermelon is spoiled you should check for any skin soft spots, bruises, or visible mold growth. 

Aspergillus niger and Fusarium avenaceum are some of the fungal organisms commonly associated with spoiled watermelons which can cause the dark spots. In addition to fungal infections, dark spots on watermelon can also be caused by physical damage (1, 2, 3). 

Half-cut watermelon will lose all its juice and ripe texture when it is spoiled, becoming a jelly that is difficult to eat and also unpleasant to smell. These are some of the obvious signs to look out for when you have a half-cut watermelon (4). 

It’s rather easy to check if a half-cut watermelon is spoiled or not because you can see the flesh of the fruit. Most of the time, the jelly is quite visible with a very dry texture and sometimes even molds growing on the surface (4).

What is the shelf life of watermelon?

The shelf life of a whole watermelon can be stored at room temperature for roughly 7 to 10 days. The length of this period, however, can vary depending on the circumstances (2, 4). 

A half-cut watermelon has a lower shelf life than a whole, uncut watermelon. This happens because watermelons have a shorter shelf life after being chopped, as there is an increased air exposure, which can cause spoilage (4).

What factors determine the shelf life of watermelon?

The shelf life of watermelon, or any fruit for that matter, can be influenced by several factors. We separate those main factor right down below:

Physical damage 

Watermelons with cuts, bruises, or other physical damage are more prone to spoilage and microbial contamination, leading to a shorter shelf life (5).


Proper temperature management is crucial for extending the shelf life of watermelons. Storing them at temperatures between 10-15°C (50-59°F) can help slow down ripening and maintain quality. Avoiding temperature fluctuations is also important (2).

Relative humidity

Watermelons require high humidity levels for optimal storage. A relative humidity of 85-95% helps prevent moisture loss and maintains the fruit’s firmness and juiciness (6).

Ethylene exposure 

Ethylene is a natural plant hormone that accelerates the ripening process. Exposure to ethylene-producing fruits or high levels of ethylene gas can lead to faster deterioration of watermelons (7).

How to tell if watermelon has gone bad?

To check whether a whole watermelon is spoiled or not might be a bit tricky, so keep in mind to check the following things when you are out to buy one (2, 4).

  • First, look at the outside of the watermelon. A fresh watermelon often has a smooth, firm rind free of significant flaws or mold. If you spot any soft areas, bruising, or obvious mold development, it could be signs of deterioration.
  • Another tip is to touch the watermelon with your fingers to feel its texture. Since a ripe watermelon must have a firm, slightly elastic texture, it can be overripe or spoiled if it seems overly soft or mushy.
  • A watermelon that is fully ripe usually has a vivid, deep green hue. However, depending on the type, the hue can change. If you note any unexpected discoloration, such as one with a dull or yellowish hue, it definitely could be a sign of rotting.
  • You can also smell the watermelon to determine whether it is fresh, a fresh watermelon normally has a mildly sweet smell, a strong, disagreeable smell or a fermented aroma may suggest food decomposition.

How to properly store and extend the shelf life of watermelon? 

If you want to properly store an extend the shelf life of watermelon you may use the following tips to keep it correctly and help maintain its freshness (2, 4):

  • Until you’re ready to eat it, a watermelon should be kept entirely as its shelf life is drastically reduced after being chopped.
  • Store the whole watermelon in a cool, dry location before chopping, like a pantry or cellar and make sure to keep it out of the sun and out of places that are too warm.
  • To keep the watermelon fresh after cutting, refrigeration is essential. You  can wrap the sliced sections firmly in plastic wrap or place them in an airtight container. Refrigerate it between 10-15 °C (50-59 °F) degrees. In addition to keeping the watermelon from drying out, this helps prevent it from collecting smells.
  • Keep in mind that freezing watermelon can cause freezing injuries in the fruit, since the water inside them can form ice crystals, which can damage the cells, the watermelon becomes mushy and loses its firmness, affecting the texture and the flavor.

What happens if you consume spoiled watermelon?

Consuming spoiled watermelon may result in gastrointestinal distress and foodborne diseases. Since the fact that harmful bacteria, including Salmonella or E. coli, can grow and infect a watermelon when it goes bad. Eating spoiled watermelon can result in symptoms such as (8, 4, 2):

  • Nausea 
  • vomiting
  • Diarrhea
  • Stomach upset
  • Food poisoning 

If you have worries or significant symptoms after eating spoiled food, speak with a medical practitioner. Remember, it’s essential to store, handle, and check the fruit for signs of decomposition before eating in order to prevent eating spoiled watermelon. 

Other FAQs about Watermelons that you may be interested in.

Can you eat watermelon on a keto diet?

Can you eat watermelon at night?

Can you eat square watermelon?


In this article, we briefly discussed how to know if watermelon is spoiled and we also talked about how to store watermelon and what happens if you consume spoiled watermelon.


1. Mailafia S, et al. “Isolation and identification of fungi associated with spoilt fruits vended in Gwagwalada market, Abuja, Nigeria.” Vet World. 2017;10(4):393-397.

2. Zhao, Ping, et al. “Microbial Spoilage of Fruits: A Review on Causes and Prevention Methods”.Food Reviews International,  2022, 38.

3. Abubakar, M. et al. “Fungi Associated with the Spoilage of Watermelon Fruits (Citrullus lanatus Thumb.”) in Jega Local Government Area, Kebbi State, Nigeria.

4. Qadri, Ovais Shafiq, et al. “Fresh cut fruits and vegetables: Critical factors influencing microbiology and novel approaches to prevent microbial risks—A review”. Cogent Food & Agriculture, 2015, 1.

5. “Means of transportation affects the physical qualities of watermelon (Citrullus lanatus [Thunb]) fruit within the Tamale Metropolis in the Northern Region of Ghana”. Journal of Biology, Agriculture and Healthcare, 2018, 8.

6. Nunes, Maria C. N. N. “Impact of environmental conditions on fruit and vegetable quality”. Stewart Postharvest Review, 2008, 4, 1-14

8. Feng, Ke et al. “Growth of Salmonella spp. and Escherichia coli O157:H7 on Fresh-Cut Fruits Stored at Different Temperatures.Foodborne pathogens and disease, 2017, 14, 510-517.

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