Americans are making fewer visits to food chains with lettuce-heavy menus as concerns mount over the cyclospora outbreak.

Last week, the Food and Drug Administration and the Centers for Disease Control and Prevention linked lettuce served at some Taco Bell restaurants to the widespread outbreak of the diarrhea-causing parasite.

Even before the official announcement, consumers appeared wary of Taco Bell’s potential connection to the outbreak.

Foot traffic fell 16.9% on July 15 compared to Taco Bell’s average daily levels this year, according to nationwide data from Placer.ai. When federal health officials publicly identified the chain as part of the investigation on July 17, foot traffic dropped nearly 19%.

Taco Bell told CNN last week that it removed the potentially compromised lettuce. But it’s not the only food chain affected by wary customers. Cava, Chopt, Panera Bread, Chipotle and Subway have all seen significant declines in visits, according to Placer. The analytics firm uses mobile data to track visits.