Pam Zekman of WBBM-TV Chicago reports nine of the 35 concession stands at Wrigley Field faced critical violations after inspectors found things such as black slime in an ice machine, food that wasn’t prepared properly and other food safety and handling violations.

Zekman reports that the city’s health department had conducted inspections when games weren’t played at Wrigley Field and other ballparks and arenas. Now they do inspections on event days.

A total of 20 critical violations were found at nine booths, three that were shut down. City inspection results resulted in more than 24 pounds of hot dogs, sausages and hamburgers being thrown out from five different concession areas.

“It’s extremely important because it is while the concession stand is working and serving customers that all the rules about food safety, food handling, are even more important,” food safety expert Kantha Shelke told Zekman.