"I always have this fear [about potlucks]," said Natalie Wardel, 23. "I'm a picky eater and I like to know where my food has been."
Food habits aside, Wardel may be wise to avoid potlucks and other social events where people bring cooked food to share. Proper food safety techniques, particularly regarding food temperature, are hard to control at potlucks, so the chance of encountering bacteria or viruses in food that cause illness can increase.
The cardinal rule for serving food is keeping it at the correct temperature.
Cold foods should be kept cold, and hot foods should be kept hot, not warm, stressed Dr. William Schaffner, chair of the Department of Preventive Medicine at Vanderbilt Medical School.
"The danger comes when foods are kept at prolonged room temperature," Schaffner said. "If the food happens to be contaminated, you get multiplication of the bacteria."
Hot or cold foods -- which tend to be main courses -- left at room temperature longer than two hours could be incubating bacteria such as staph and salmonella, which cause food poisoning, or viruses such as norovirus, which can cause diarrhea. As food temperature rises above 40 degrees or drops below 130 degrees, the chances of microbe growth increase.
Also, food may remain out until well after the first round of eating. By the time guests go back for seconds or if new people arrive late, dishes may have been sitting out for several hours.
Others are less concerned about potlucks, though the time food sits out can still be a problem.
Mark Kantor, an associate professor of Nutrition and Food Science at the University of Maryland, is more concerned with what happens to the food after all the guests have gone home.
"You probably shouldn't keep leftovers," Kantor said, noting that by the time the party is over, food will have been sitting at room temperature well beyond the recommended two hours.
While Wardel said she was hesitant to eat food prepared in other people's kitchens, not knowing the cleanliness of those kitchens, Kantor said home preparation should not be a cause for worry.
Cooks are likely to take as much care during food preparation as if they were cooking for themselves, Kantor said, because the food will likely be consumed by family and friends. Proper food safety techniques include hand washing, using fresh, clean ingredients and avoiding cross contamination.
"You might want to show off a bit, what you've made," Kantor said. "People are probably going to do a good job in what they prepare."
But even if preparation goes smoothly, the food presentation can often become unappetizing.
Wardel recently made a post to her personal blog about how much she disliked potluck dinners, prompted by a party she attended where guests brought different kinds of enchiladas. By the time they were served, however, the greasy, congealed cheese was decidedly unappetizing.
"It's really hard to keep potluck food looking good," Wardel said.
Wardel suggests arranging ahead of time to complete the final steps of the dish at the host's house to ensure a fresh, hot dish that has not had time to cool.
"Think ahead about the final presentation a little bit," Wardel advised.
In the moment, the pressure to be polite and try all the food can be stressful.
"I feel like you have to be nice, go through the line, and leave with an empty plate," Wardel said.
Kantor endorses a bit of subterfuge in order to discretely toss a plate of unappetizing food.
"Most people won't stand there and watch what you eat and don't eat," Kantor said. "You're just there being social, doing what everyone else is doing."
Wardel has her own proven tactics for evading people who urge her to eat more of their dishes. She claims to be on a diet.
"Or else you're the girl who throws away a full plate of food," she said. "And you don't want to be that girl!"
Some preparation beforehand can put many potluck fears to rest and keep guests germ-free. Keeping food at the proper temperature using ice or a heater, having plenty of serving utensils and fresh plates on hand, and making labels so that guests know what is in each dish, can help calm a nervous eater.