The Health Risks of Double Dipping Chips

The New York Times puts any discussion of avocado cholesterol aside for a moment, and looks at the bacterial risks associated with double dipping chips in an avocado dip. Reporter Harold McGee managed to locate a Clemson University study that explored the likelihood that bacteria would be transferred to by the dreaded double dipping of chips or crackers. McGee reports on the study, in which 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. On average, McGee, reports, the
students found that three to six double dips transferred about 10,000
bacteria from the eater’s mouth to the remaining dip. Because each
cracker picked up between one and two grams of dip, sporadic double dipping in a cup of dip would transfer at least 50 to
100 bacteria from one mouth to another with every bite. The bottom line, says Clemson food microbiologist Prof. Paul L. Dawson, is this: "Before
you have some dip at a party, look around and ask yourself, would I be
willing to kiss everyone here?" Read more in the New York Times.