An Introduction to Community & Public Health 8th Edition by James McKenzie, Pinger

Exercise 9

Unfortunately, by the time the investigation began, all the picnic food had been discarded, and no samples were available for laboratory testing. To determine which food at the picnic might have caused the outbreak, you need to calculate attack rates for people eating each food as well as for people not eating each food. Using Table 1 , the Attack Rate Worksheet, calculate the attack rates for those who ate and did not eat each food served.
Which food would you most suspect of causing the illness?
TABLE 1 Attack rate Worksheet