Double dipping - the risk finally quantified

In case you missed it, the New York Times did a story on the phenomenon known as "double-dipping, "made famous by The Seinfeld Show This is when you dip a chip into a dip, and then dip into the dip again with the same end of the chip, thereby polluting the entire bowl of dip with your used chip. Of course, it was George who was guilty of this infraction and was set upon by another party-goer who denounced him to the crowd.

But how unhealthy is the practice? Is it just another over-reaction to the interaction with others? Not so, says Professor Paul Dawson , a microbiologist at Clemson University. In a study inspired by the Seinfeld episodes, tests showed that double-dipping did result in significant quantities of microbial activity, especially when more than one dip was done.

• They found that three to six double dips transferred about 10,000 bacteria from an eater's mouth to the remaining dip sample.
  
  
• "I was very surprised by the results," Dawson said in a telephone interview Thursday. "I thought there would be very minimal transfer. I didn't think we would be able to detect it."
  
  
• The professor said the students' research didn't get into the risk behind such a bacteria transfer, but they got the idea.
  
  
• "I like to say it's like kissing everybody at the party -- if you're double dipping, you're putting some of your bacteria in that dip,'' Dawson said.

Dawson is the scientist who last year disproved the famous five second rule that says that food that drops on the floor stays clean for five seconds and can be eaten. The results here showed that quick retrieval resulted in 150-8000 bacteria. Left an entire minute, however, food collected ten times that amount. A quick pickup therefore is better than eating off the floor, but no guarantee of food safety.

 - Paul Banas