Fresh produce on sandwiches — but not sprouts — served at Jimmy John’s restaurants in Denver has been linked to an E. coli outbreak.

Eight people became sick after eating at three Jimmy John’s restaurants in Denver between Oct. 5 and Oct. 9, said Alicia Cronquist, epidemiologist for the Colorado Department of Public Health and Environment.

None of the eight were hospitalized and all have recovered, Cronquist said.

The E. coli was not found in sprouts, the source of several previous outbreaks linked to the company, Cronquist said. As of Nov. 1, Colorado officials and the Food and Drug Administration, which is working with Colorado in its investigation, did not know what produce item had the E. coli, she said.

Both the FDA’s national and its Denver offices are working with Colorado, Dave Steigman, an FDA spokesman, said Nov. 1. Steigman said FDA hoped to know more about the source of the outbreak by Nov. 6 or 7.

Cronquist said the outbreak is likely over.

“We’re not seeing any ongoing cases, and we’re fairly confident this was a single lot or batch,” she said.

Since 2008, several salmonella and E.coli outbreaks have been linked to sprouts served at Jimmy John’s. In the latest, in February 2012, 12 people in five states were sickened by E. coli found on Jimmy John’s sprouts.