Federal officials say a Salmonella Typhimurium outbreak that was linked to packaged salads from BrightFarms has come to an end.

A total of 31 people infected with the outbreak strain of SalmonellaTyphimurium were reported from four states – Wisconsin, Illinois, Minnesota and Pennsylvania. 

Investigators from the Centers for Disease Control and Prevention say it’s probable there were more people sickened in the outbreak. The true number of sick people in an outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not specifically tested for Salmonella infection, which can mimic other illnesses.

Illnesses started on dates ranging from June 10 to Aug. 18. Sick people ranged in age from less than 1 year to 86 years old, with a median age of 44. Sixty percent were female. Four people were hospitalized, but no deaths were reported.

State health officials interviewed people about the foods they ate in the week before they got sick and collected shopper card records to determine what products they bought. Of the 27 people interviewed, all but one reported eating leafy greens. Among those 26 people, 22 reported eating prepackaged salads.

Interview data and shopper card records show that 15 people ate or bought a variety of BrightFarms packaged salad greens before they got sick, including Sunny Crunch, 50/50 Spring & Spinach, Harvest Crunch, and Butter Crisp. 

The U.S. Food and Drug Administration FDA conducted a traceback investigation and identified BrightFarms greenhouse farm in Rochelle, IL, as the likely source of packaged salad greens bought by the patients.

Investigation showed that people in this outbreak got sick from the same food. Whole-genome sequencing (WGS) showed that bacteria from sick people’s samples were closely related genetically.

The FDA inspected BrightFarms greenhouse farm in Rochelle, IL, and collected samples for testing. They found a different Salmonella strain in an indoor pond where BrightFarms grew lettuce. The CDC’s PulseNet system did not identify anyone who got sick from this strain. 

However, the FDA found the outbreak strain of Salmonella Typhimurium in an outdoor stormwater drainage pond beside the farm. However, investigators were unable to determine how this pond became contaminated.

About Salmonella infections
Food that is contaminated with Salmonella bacteria usually does not look, smell or taste spoiled. Anyone can become sick with a Salmonella infection, but infants, children, seniors and people with weakened immune systems are at higher risk of serious illness because their immune systems are fragile, according to the CDC.

Anyone who has developed symptoms of Salmonella infection should seek medical attention. Sick people should tell their doctors about the possible exposure to Salmonella bacteria because special tests are necessary to diagnose salmonellosis. Salmonella infection symptoms can mimic other illnesses, frequently leading to misdiagnosis.

Symptoms of Salmonella infection can include diarrhea, abdominal cramps, and fever within 12 to 72 hours after eating contaminated food. Otherwise healthy adults are usually sick for four to seven days. In some cases, however, diarrhea may be so severe that patients need to be hospitalized. 

Older adults, children, pregnant women and people with weakened immune systems, such as cancer patients, are more likely to develop a severe illness and serious, sometimes life-threatening conditions.

It is possible for some people to be infected with the bacteria and to not get sick or show any symptoms, but to still be able to spread the infection to others.

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