There now are 37 Salmonella infections in Ottawa, most linked to a catering company that served meals to schools and day care centers, the city’s public health department reported Monday.

The outbreak total includes 33 children, ranging in age from 15 months to 18 years old. Three required hospitalization but have since been released. The children all attended one of seven schools or a single day care center.

Two of four ill adults appear to be part of the outbreak; two cases may be unrelated, the health department said in a news release.

Still no official word on what caused the outbreak of Salmonella poisoning, although the owner of The Lunch Lady catering company, implicated as the source, said earlier that investigators were looking at ground beef used to tacos and lasagna.