An outbreak of explosive diarrhea that sickened at least 500 people in Florida was triggered by bagged salad.
Researchers at the Centers for Disease Control and Prevention (CDC) linked last year’s cluster of illnesses to bags of salad contaminated with a parasite known as cyclosporiasis.
Many cases were linked to a specific brand of romaine-only Caesar salad sold by a specific supermarket chain, but neither was mentioned.
Commonly found in feces, the microorganism is spread onto food via contaminated water – which then causes infection when ingested by humans.
Patients with the disease experience watery diarrhea, loss of appetite, cramps, bloating and nausea. The illness can last for more than a month, although most cases resolve within a few days.
A disease outbreak in Florida has been linked to a parasite contaminating bagged salad
The parasite cyclosporiasis is shown above at different stages of its life cycle. It is shown in its immature form at the top. Shown at bottom left is a ruptured parasite that has released two younger cyclosporiasis and bottom right is shown when it can cause infection in humans
The CDC revealed the cause of the disease outbreak that occurred last year in a report published yesterday.
The Florida Department of Health investigated 457 of the 513 reported cases to investigate the source.
They found that 200 patients had eaten a pre-washed bagged salad, and 85 of them had eaten the same brand of Caesar salad from the same supermarket chain that contained only romaine lettuce.
An international link was ruled out when it emerged that 330 of the patients had not traveled internationally before falling ill in the spring and summer of 2022.
Researchers were unable to identify the farm where the lettuce leaves had become contaminated.
But in the past, outbreaks have been caused when cattle were allowed to graze near fields where lettuce was grown.
Their droppings, along with the parasite, then enter the water supply that is sprayed on the lettuce, spreading the pathogen and causing disease.
The disease-causing pathogen can then infect plants from other farms in factories when they are mixed together while the salad is being prepared. It can also end up on machines, further spreading the disease.
To prevent the disease, the CDC recommends washing all fresh produce before eating or cooking with it.
They also say that an opened bag of refrigerated leafy greens should be consumed within two days.