A Case of Food Poisoning

Background

An outbreak of food poisoning occurred the last week of June, affecting twothirds of the 1700 persons who attended a dinner in Port Allen, Louisiana. A problemnaire to obtain information concerning the illness was administered to 122 persons. Of this sample, 82 (67.2%) reported illness. Physicians treated 32 patients (26.2%); 9 (7.4%) required hospitalization. Dinner was at 6 P.M. Sunday. 
Laboratory analysis yielded positive cultures of the etiological agents from the leftover shrimp, potatoes, corn, and hogshead cheese, and from 7 of 15 stool samples from patients. The person who collected the food stored all of it in one container. 
Potatoes were purchased from a farmer. They had been stored in a root cellar and were transported loose in a pickup truck. The morning of the dinner the potatoes were washed, peeled, and boiled until tender. The pots were covered with aluminum foil and transported unrefrigerated 50 miles to the dinner. 
Corn was purchased from a produce market. The night before the dinner, the corn was shucked and kept in the wooden boxes in which it had been purchased. The day of the dinner, the corn was boiled. For transport, it was wrapped in aluminum foil. 
Hogshead cheese was purchased the morning of the dinner along with the salt meat. The headcheese and salt meat were kept refrigerated by the delicatessen. After purchase, they were stored unrefrigerated until dinner. (Read labels in the deli section of your grocery store to ascertain the ingredients in headcheese.) 
Raw shrimp was purchased at one location and shipped to a second location in standard wooden seafood boxes. It was boiled on the morning of the dinner and placed back into the boxes. After being covered with aluminum foil, it was transported 40 miles in an unrefrigerated truck to the dinner. An inspection of the wholesale seafood establishment was undertaken six days later. The investigation revealed that the shrimp had been boiled in 300lb. batches in the following manner: A batch was placed in a container until the water came to a rolling boil; then the gas was turned off, and the shrimp kept in the hot water for 15 minutes. 

problems

1.Identify and discuss the etiological agent of this outbreak.
2.Was it food infection or intoxication? Discuss the supporting evidence for this conclusion.
3.Which food item was contaminated and how did the food get contaminated?
4.Briefly describe why you eliminated the other major causes of food poisoning.
5.Discuss the branch of microbiology introduced in this case and identify the type represented here.