When it comes to double dipping, what’s the rule? Generally, the practice of taking a bite of a chip and then dipping it again is considered inappropriate in polite society. In public gatherings, it is certainly frowned upon– would you want to dip something into traces of someone else’s DNA and then consume it? Don’t forget about the bacteria that your chip is likely covered in. It doesn’t exactly make for a savory experience.
Essentially, the rule is that you can double dip your dip-loving heart out if it’s your own bowl of chips and dip. However, if you’re in public at a gathering with other people, be prepared to get some rightfully deserved hate and anger thrown your way if you decide to do so. After all, no one wants that happening. Don’t be selfish. But is this just a gross action you hope you never witness, or an actual hazard to our health? We looked into the science behind it to find out.
Generally, bacteria grow when they have something to eat and they are let to have some material to munch on. The longer a dip is out of the fridge and sitting in a communal bowl, the more opportunity that it has to attract bacteria. Not to mention that if some lone jerk decides to double dip, there may be additional (yuck) bacteria left in the dip. Those bacteria will all proliferate at an endless rate until second by second, minute by minute, there are steadily more bacteria hanging out than there were when the dip started out fresh.
A Clemson University team designed experiments involving bacterial transfer, dip acidity, and dip type to try and get some answers. They certainly did, and they were exactly what you would expect. In the end, they found that any vessel that had been bitten once and then returned to the dip certainly did have more bacteria than a fresh chip or cracker would (as you can imagine). 1,000 bacteria more a milliliter enters the arena with bitten crackers.
Dip constitution may also have played a part as well, as acidity of the dips. Crackers were dipped into differing pH levels and then tested for bacteria, and the more acidic solutions actually caused the amount of bacteria to go down over time. Salsa actually will take on 5x the bacteria that dips made out of chocolate and cheese will. However, the salsa levels go down in two hours and are about the same as the chocolate and cheese.
So is double-dipping merely a socially frowned upon occurrence, or is it gross for a reason? It’s gross for a reason. The human body and mouth can sustain a number of viruses and bacteria, which can also be transmitted person to person and infect individuals in a domino-style effect. The plague, the flu, Legionnaire’s and tuberculosis are all transmitted through saliva. They can be picked up from a cough, surface, or a sneeze. So yes, there is cause to have concern about double dipping with strangers. Don’t do it, and don’t do it yourself for best results. The germs could not only rival those found on the welcome mat of a family burger restaurant in New York— they could actually be worse.