You're at a party. A man walks up to the snack table, grabs a chip and dips it in a big bowl of salsa. A little weird, you think, since everyone else is just spooning a little on their plate, but it's not a huge deal. Then the unthinkable happens: He goes in for a second dip. With the same chip.
That's double dipping, and at most social gatherings it's considered a major party foul. Why? Because each second dip transfers germs from the eater's mouth to the bowl of dip. Exactly how many is unclear. A Clemson University student project put the number of bacteria transferred from mouth to dip at about 10,000 for every three to six double dips, while the television show "Mythbusters" estimated just five to 10 per one double dip. Either way, at least a little bacteria is getting transferred [source: Jarvie].
There are a few things you can do to spare your party guests from the double-dipping menace. Offer small bowls and plates onto which they can spoon dip or simply serve food sized for a single bite. That way everyone can go home happy and healthy.