As you can see, it is possible to be a disease detective, even in the home! This case study was based on an actual investigation by a real epidemiologist. The epidemiologist in real life asked himself more questions:
The epidemiologist went to the shop where the mandarin orange was sold, and traced all the people who also bought the mandarin orange from there.
Out of 8 families who bought the oranges, 6 had symptoms of mild food poisoning after eating.
The epidemiologist then took the mandarin orange back to his lab and showed that the amount of preservatives added to the mandarin orange was very high.
He then wrote a report to the newspaper, advising the people not to eat food that might contain too much preservatives. He also wrote the government, recommending better food quarantine.