Step $1$: Read the case study.

A local health department epidemiologist investigated an outbreak of gastrointestinal illness thought to be associated with a college cafeteria. There had been many complaints about the quality of the cafeteria's offerings; it appeared that the students' worst expectations were confirmed when a total of $24$ students visited the college's infirmary. The visits began on the day following their consumption of the food and continued during the middle of the night into the next day. Students complained of nausea, diarrhea, fever, vomiting, and cramps. The health department's investigation revealed that all $24$ ill students had eaten in the cafeteria immediately before the outbreak. The times between eating in the cafeteria and the development of active symptoms ranged from approximately $20$ to $36$ hours.

Table $1$: Partial List of Pathogens That Cause Foodborne Illness