Why are so many people getting sick from eating cucumbers?

Salmonella outbreaks linked to cucumbers have sickened hundreds of people since last year, drawing attention to the problem of contaminated irrigation water on farms.

A salmonella outbreak tore through the country last spring and summer, infecting more than 550 people and sending 155 to the hospital.

The likely culprit wasn’t raw eggs or undercooked chicken but an innocuous salad staple: cucumbers.

One year later, cucumbers are once again making people sick — and federal officials say that one of the same Florida farms is once again involved. Forty-five people in 18 states recently contracted salmonella in an outbreak linked to cucumbers from Bedner Growers in Palm Beach County, setting off a widespread recall that has affected everything from California rolls sold at Target to banh mi sandwiches served at a North Carolina high school.

The Food and Drug Administration has yet to explain how the cucumbers linked to the current outbreak became contaminated; the investigation is ongoing. But last year, the agency found that Bedner Growers had used untreated canal water for irrigation — and that the water was contaminated with one of the salmonella strains that had made people sick.

Cucumbers and other fresh produce may be a surprising source of salmonella, which can cause diarrhea, stomach cramps and fever, as well as more serious health problems that can turn fatal. Heat from cooking can kill the bacteria, but fruits and vegetables that are eaten raw, like cucumbers, can be unsafe once they are contaminated. That means it’s particularly important to protect fresh produce from pathogens lurking in water used for irrigation or washing.