At least 52 people have been sickened with E. coli in an outbreak linked to Federico’s Mexican Restaurant in Litchfield Park, Ariz. Of those ill, 18 have been hospitalized, with some patients experiencing kidney failure. Maricopa County Health Department spokeswoman Jeanene Fowler said health officials are still working to determine the source of contamination at the establishment, and that the owners were cooperating fully with the investigation. “We’re still doing our due diligence in investigating the outbreak and interviewing the people affected,” Fowler said. The restaurant voluntarily closed for three days to clean all of the surfaces and bring in new food, and has since reopened. Food safety law firm Marler Clark has filed lawsuits on behalf of two victims who allegedly fell ill with E. coli O157:H7 infections after eating at the restaurant.