- Bacteria found to be transferred through double dipping
- Study inspired by Seinfeld episode
- Salsa spreads more bacteria than cheese or chocolate dips
- Expert says most bacteria in mouth not harmful
Remember those Tostitos you double dipped into the salsa con queso with your buddies on Super Bowl Sunday? Dipping into that communal bowl may have been a mistake.
Recent research shows that double dipping really does transfer bacteria.
Paul Dawson, professor of food microbiology at Clemson University in South Carolina, conducted a study with nine undergraduate students in the spring of 2007. The study will be published in the Journal of Food Safety within the next six months, he said.
Dawson said the study was inspired by a 1993 episode of 'Seinfeld' entitled, "The Implant."
In the episode, George Costanza stands at the snack table at a party dipping the same chip into a bowl of dip. Timmy, eyeing him from across the room, approaches George and says, "Did. did you just double dip that chip?"
"'Double-dipped?' What are you talking about?" George says.
"You took the chip. You took a bite. And you dipped again," Timmy says, pointing at the dip.
"So.?" George says.
"That's like putting your whole mouth right in the dip!" Timmy says.
But Timmy's feelings about double dipping may not be so far from the truth.
"High levels of bacteria were transferred through double dipping," Dawson said.
Dawson said the experiment was done in a controlled setting, where one student bit a chip or cracker and dipped it in a bowl of salsa, cheese or chocolate. The team used sterile water as a control.
The team found more bacteria in the salsa than in the cheese or chocolate because salsa has a runny consistency, he said.
The team also measured the bacteria levels of the salsa after leaving it sit for two hours.
"The low acidity of the salsa lowered the bacteria levels," Dawson said. "But it lowered to the same level as the cheese and chocolate."
Dawson said in a real world scenario, more people at a party will dip into bowls. As partygoers eat more dip, the ratio of bacteria to dip left in the bowl becomes higher. The dip also contains more active bacteria if it is warmed, he said.
But bacteria normally in the mouth are not harmful, Dawson said.
"It's more of a 'yuck' factor initially," he said.
Yet double dipping can lead to the spread of a cold or the flu, Dawson said.
"This is not necessarily high-impact or high-profile food safety issues," he said. "But grabs attention and is a nice vehicle to begin the discussion on food safety and food handling."
Dawson said double dipping is a personal choice.
"I'm not the dipping police," he said.
Judith Trevino, now a graduate student at Clemson, participated in the study as a senior. Double dipping is something that is discussed a lot, she said.
"It was a scientific experiment we could do that other people would be interested in," Trevino said.
Trevino said she figured the experiment would result in bacteria transfer.
"Don't double dip unless you're comfortable sharing saliva with everyone in the room," she said.
Ben Schickert, a sophomore in the College of Business Administration, said he double dips all the time when he's by himself.
"The study is interesting, but it won't make me think twice about double dipping," he said. "I'll double dip if I want to."
