How did George soper track Down Mary Mallon?

George Soper, a sanitary engineer, tracked down Mary Mallon, also known as "Typhoid Mary," by investigating a typhoid fever outbreak in New York City in 1906. He conducted a thorough study of the families affected and discovered that Mallon had been the common link, as she worked as a cook in multiple households where the illness occurred. Soper's meticulous research, including interviews and testing of her stool samples, ultimately confirmed that she was a healthy carrier of the typhoid bacteria, leading to her eventual isolation.