Core Tip: How should leftover watermelon be stored? Under the guidance of Associate Professor Ruan Wenke from the College of Animal Science at Beijing Agricultural University, a reporter conducted a bacterial culture experiment. The results were surprisingly unexpected, revealing that watermelon covered with plastic wrap actually harbored more bacteria.
Recently, as temperatures have continued to rise, many citizens have been buying watermelon to cool down. However, a reader recently called our hotline, saying, "My mom and I disagree on how to store watermelon. She thinks leftover watermelon should be put directly in the fridge, but I think we should seal the cut surface with plastic wrap. There are so many other foods in the fridge, so it's bound to have bacteria, and the watermelon can easily get contaminated."
So, how should leftover watermelon be stored? Under the guidance of Associate Professor Ruan Wenke from the College of Animal Science at Beijing Agricultural University, a reporter conducted a bacterial culture experiment. The results were surprisingly unexpected, revealing that watermelon covered with plastic wrap actually harbored more bacteria.
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Plastic Wrap Isn't Safe; Watermelon Should Be Eaten Soon
This result was a complete surprise to everyone. Professor Ruan explained that there are specific reasons for the increased bacterial count in watermelon flesh stored with plastic wrap.
First, watermelon flesh naturally contains a certain amount of bacteria. As the plant grows, it secretes substances that inhibit bacterial reproduction. This is why a sweet potato in the ground won't rot. However, once a watermelon is picked, the production of these inhibitory substances stops, allowing the bacteria inside to begin multiplying.
Second, covering the cut surface of the watermelon with plastic wrap creates a relatively sealed environment. This preserves the watermelon's internal moisture and prevents its temperature from dropping quickly to 4°C, providing favorable conditions for bacterial growth. Bacterial reproduction is inhibited at 4°C.
"If the bacteria are highly virulent, even a small number can cause illness," Professor Ruan stated. For less virulent bacteria, he emphasized that they should not be ignored either, as an excessively large number can still have adverse effects on the body. Therefore, Professor Ruan recommends that watermelon stored with plastic wrap should be eaten as soon as possible.