On the Monday after the picnic - held July 27th and 28th - an unusually high number of people began reporting symptoms of nausea, vomiting, headache and diarrhea to their doctors. Four people were hospitalized briefly after experiencing dehydration from loss of fluids. Stool samples confirmed that ill individuals had contracted Salmonella Enterica infections. All had eaten at the Irish picnic - a fundraising event for St. Patrick school and church.
Health officials are now conducting interviews with picnic attendees - both those who became ill and those who didn't - to determine which foods could have been potential sources of the bacteria.
While the main offering at the picnic was pulled pork - about 20,000 pounds of it - many other foods were also served.
"It was an extensive menu," says Lori McDonald, Regional Health Officer for the Tennessee Department of Health. "Not just the pulled pork. It was chicken, hamburgers, hot dogs, all the toppings, plus potato salad, coleslaw, lettuce, tomato, mustard and all that jazz. And then all the desserts. Ice creams, frozen yogurts, italian ices."
Any of these foods may have been contaminated, she says. The large variety of foods will make it very difficult to pinpoint the source.
"At this point we have no idea what it is," says McDonald. "A lot of times we never identify the source, but we will give it the old college try."
One thing officials do know is that food handlers at the event were in full compliance with health codes.
Two environmentalists from the state health department visited each food stand to make sure that food was being properly prepared and served.
"They scored extremely high," says McDonald. "They were hand washing, they were using gloves. Every time a shoulder came off the barbecue the internal temperature was checked. They did everything right. It's been unfortunate for them because they feel terrible."
She says it's also possible that the contaminated food was brought by an individual rather than served at the picnic.
The investigation is also complicated by the fact in many instances, two people shared food but only one person became sick, says McDonald.
"Several people shared their barbecue sandwiches, and the husband would be sick but the wife wouldn't."
The good news, says McDonald, is that the percentage of people who got sick was relatively low.
"Based on 18-20,000 people attending, even if you guessed 100 people were sick, the attack rate is extremely low. It's been very difficult to track it down."
However, fewer victims means less information about the source of the bacteria.
McDonald encourages any individuals who became ill after eating at the St. Patrick's fundraiser to go to their local healthcare provider so that a stool sample can be collected.
Most victims became sick 1-2 days after eating at the picnic and recovered in under a week; however some people bought food and took it home for later consumption, and therefore may still get sick.
Officials have collected a sample of barbecued pork from a man who brought it home from the event and became sick after eating it. A culture from the sample is being grown at a state lab and will be tested for the outbreak strain of Salmonella within the next couple days.
