The FDA issued a warning letter to Jensen Farm on the 18th October stating that a “significant percentage of swabs [taken from various places around the farm] … tested positive for outbreak strains of Listeria monocytogenes demonstrates widespread contamination throughout your facility and indicates poor sanitary practices in the facility”.
Quoting from their Draft Guidance for Industry, Guide to Minimize Microbial Food Safety Hazards of Melons, they recommended using packing equipment that was easy to clean and sanitize, ensuring that contamination and cross contamination do not come from melon wetting and brushing operations and that the melons are cooled as soon as possible after harvest to prevent growth of human pathogens.
The outbreak is the biggest in recent history, with a death toll of 28 (as of the 25th October) and 133 cases of illness in 26 US states.