According to a recently published study, the United Kingdom was hit by two bacterial outbreaks related to (water)melons in 2021. It was already known that the Salmonella Brainup outbreak that affected several countries and whose source could be traced back to melons from Honduras also reached the UK. However, there was also an E. coli O157 outbreak that was also associated with imported watermelons, according to a study published in the Journal of Food Protection.
In July and August 2021, there were 17 cases of Shiga toxin producing E. coli (STEC) O157:H7 in the UK. From the assessment of the data of a STEC surveillance questionnaire and the analysis of the answers of an adapted hypothesis-generating questionnaire, eating pre-cut watermelon from a supermarket that had brought the product from Europe was identified as the source.
The watermelons came from three companies from Spain. The fruit was cut in a processing facility in England and kept for five to six days. There were no whole or pre-cut watermelon samples processed in the days prior to the onset of symptoms available for testing.
As for the melons from Honduras, in June 2021, the authorities of the Central American country carried out an inspection at the relevant cultivation farm and a risk management plan was drawn up. During the harvest, a lot of rain had fallen for three days. Salmonella Brainderup corresponding to the outbreak strain was found on the surface of a wash tank in one of the Honduran processing facilities where Galia melons were packaged.
“Various sources of infection were possible. The most likely is that unusually high rainfall in Honduras during the harvest period resulted in sewer overflow and the contamination of the irrigation water for melons,” scientists said.
Post-harvest contamination by an infected processor or cross-contamination with other products during the transport process may also have occurred.