Chicago Health officials are trying to determine if a restaurant represented at the Taste of Chicago is linked to reports of salmonella poisoning.
Pars Cove Persian Cuisine had a booth that served food at last week's festival.
Since then at least 17 people have become sick, with at least five of the cases caused by salmonella bacteria.
All 17 people ate at the same booth.
Officials say this is the first time in at least 20 years that a food born illness has been linked to the Taste of Chicago.