If you are at a Super Bowl party this weekend, you may want to avoid the dip:

Dip Once or Dip Twice?

The concern is “doubling dipping” – a concern first given wide publicity by an episode of “Seinfeld.” The problem mentioned in that episode is that some people take a bite of a chip, and then stick the chip back in the dip bowl a second time. To determine whether this transgression does indeed transfer germs, students tested it:

The team of nine students instructed volunteers to take a bite of a wheat cracker and dip the cracker for three seconds into about a tablespoon of a test dip. They then repeated the process with new crackers, for a total of either three or six double dips per dip sample. The team then analyzed the remaining dip and counted the number of aerobic bacteria in it. They didn’t determine whether any of the bacteria were harmful, and didn’t count anaerobic bacteria, which are harder to culture, or viruses.

There were six test dips: sterile water with three different degrees of acidity, a commercial salsa, a cheese dip and chocolate syrup.

The results?

On average, the students found that three to six double dips transferred about 10,000 bacteria from the eater’s mouth to the remaining dip.

It makes you wonder if the communal dip bowl will go the way of tap water eventually. Will some company invent single-serving dips? Or will a new social protocol evolve?

Here, by the way, is the scene from Seinfeld:

[See previous PSA]