Half a watermelon under food wrap on a supermarket shelf looks tempting in the heat. It was exactly against such a purchase that the Úrad verejného zdravotníctva SR (ÚVZ SR, Public Health Authority of Slovakia) spoke out on August 15. Sliced melons and watermelons, experts warned, can be contaminated with bacteria, and under the wrap in the heat, they multiply faster than you can carry the purchase home.
The contamination mechanism is simple. Bacteria live on the watermelon rind, which almost no one washes before slicing. The knife transfers them directly into the flesh. Then the piece is wrapped in plastic and placed on the shelf, and in the heat, under the wrap, a greenhouse effect is created where microorganisms multiply every hour. The watermelon itself may look and smell perfectly normal.
What ÚVZ SR advises
Sanitary doctors published specific recommendations — they concern both buying and home storage:
- Buy whole watermelons. If you still take sliced ones, only buy them in stores where portions are kept in refrigerated boxes, not at room temperature.
- Wash the watermelon before cutting. The surface should be thoroughly rinsed under running drinking water, even if it looks clean.
- Use a separate knife and cutting board. Use exclusively clean utensils for slicing and wash your hands beforehand.
- Store in the refrigerator. Cut watermelon should be kept in a clean airtight container or under plastic wrap, and definitely separate from raw meat and fish to avoid cross-contamination.
- At the beach or picnic — eat faster. If you take sliced watermelon with you to the swimming area or outdoors, eat it as soon as possible: bacteria multiply rapidly in the heat.
ÚVZ also reminds about the general rule for the summer season: all fruits and vegetables should be washed with drinking water, and leafy greens and small berries should be rinsed thoroughly in parts. Long soaking in water is not recommended: it worsens the quality of the fruits and speeds up their spoilage.
Why this is really dangerous
The Slovak message does not name specific pathogens, but global practice provides the answer. Sliced melons and watermelons regularly become sources of salmonellosis outbreaks — the American CDC has recorded such outbreaks with hospitalizations. Contamination can occur in the field, during transportation, or packaging, so washing the rind is not an unnecessary precaution but basic hygiene.
Salmonellosis for a healthy adult is a few difficult days with fever and stomach upset. But for children, elderly people, and those with weakened immunity, infection can end in hospitalization.
What to do
The simplest solution, which sanitary doctors suggest, is to buy a whole watermelon, wash it at home, and cut it with a clean knife. This is not a ban or panic: ÚVZ only warned about the seasonal risk that repeats every summer. But if you see half a watermelon warming on a shelf without refrigeration in a store — just walk past it.
