At least 163 people became sick after eating tainted salads at McDonald's restaurants in 10 states, including Minnesota.
The U.S. Food and Drug Administration says the Cyclospora parasite made its way into these salads, USA TODAY reports. Typically, these parasites are transmitted via fecal matter contamination.
Three cases were reported in Minnesota last week. Other states affected include Iowa, South Dakota, Wisconsin, Nebraska, and Missouri. The restaurant quit selling salads at around 3,000 locations in those states, among others, until the chain was able to work with a different lettuce mix supplier.
Cyclospora infections can take up to six weeks to be identified, says the FDA. According to the Centers for Disease Control and Prevention, the most common symptom is diarrhea.