A lunch-time food poisoning outbreak has affected 25 students. You are part of the Microbiology Investigation Team. Examine the evidence, plot the data, eliminate weak leads, identify the contaminated food, name the microorganism, and write the final case report.
Collected from the lunch service:
Microbial findings from food testing.
Recorded during interviews after the outbreak.
Time between lunch and illness onset.
Food holding temperatures measured after service.
Surface contamination checks.
Select foods you can confidently rule out as the main outbreak source.
Plot temperature data from Evidence E. Use the graph to justify which food was stored in unsafe conditions.
Best-supported conclusion: Chicken sandwich. Most likely microorganism: Salmonella. Main reason: chicken was left out for 3 hours in unsafe warm conditions, allowing bacterial multiplication. Yogurt contains useful bacteria, fruit juice tested clear, and the salad may present a secondary hygiene concern but does not fit the strongest overall evidence pattern.