572 Cyclosporiasis cases were reported in Southeast Michigan as of July 4, up from 170 on June 30, prompting state officials to issue added food-safety guidance.
MDHHS said it is still seeking a direct cause, but U.S. and Canadian outbreaks have previously been tied to fresh produce including bagged salad mixes, cilantro, basil, raspberries, snow peas and green onions.
New advice urges consumers and commercial kitchens to favor whole lettuce heads over bagged mixes, wash produce under running water, strip outer layers where possible and cook foods when they can.
158 degrees Fahrenheit is the recommended cooking threshold to kill Cyclospora, with officials stressing extra caution for chemotherapy patients, transplant recipients, infants, young children and older adults.
Cases remain concentrated in Monroe, Lenawee, Washtenaw, Wayne, Shiawassee, Jackson, Oakland and Livingston counties as officials warn the intestinal illness can last days to more than a month if untreated.