Centers for Disease Control and Prevention

“ Over the next 6 weeks, a public health team – which included persons from the local and state health departments and from the CDC – continued this extensive investigation, collecting additional data and samples, conducting numerous interviews, and carrying out complex studies. Ultimately, investigators identified a total of 751 persons with cases of Salmonella gastroenteritis. With an outbreak this large, investigators were initially optimistic that they would be able to find a common pattern or thread that could explain the occurrence of illness in so many people. ”

“ After receiving the initial reports of suspicious activity involving certain persons, public health personnel also began to interview restaurant managers about the behavior of disgruntled employees as a means for assessing the possible occurrence of an intentional act. ”

“ At the end of this extensive investigation, they concluded that: (1) the illness was associated with salad bar consumption; and (2) because cases of illness occurred in two distinct time clusters, transmission of Salmonella Typhimurium probably involved some sort of complex transmission mechanisms. The investigators could neither rule out nor prove intentionality. The investigators recommended that all restaurant food handlers be healthy and have negative stool cultures before being permitted to return to work. ”