Does double dipping in a sauce spread germs?

If I double dip a chip into a bowl of ranch, then it will have three times more bacteria than the bowl of ranch where it was only dipped once.

• Three bowls

• Small bottle of ranch

• Ruffle chips

• Three prepared petri dishes

• Three cotton swabs

• Three pieces of tape

• Small carboard box

• Marker

Dependent Variable-The amount of bacteria in each ranch bowl.

Independent Variable-The amount of dips of each container, zero dips, one dip, two dips.

Constant-The same amount and type of ranch sauce and the petri dishes, and the chips.

Control-The bowl of ranch I didn't dip a chip in.

Does double dipping in a sauce spread bacteria? My hypothesis is “If I double dip a chip into a bowl of ranch, then it will have three times more bacteria than a bowl of ranch where the chip was only dipped once”. I think my hypothesis was partially correct. I did predict there would be an increase in the bacteria between the one dip and the double dip, but I didn't exactly predict the right amount it increased by. In my results the double dip sample increased by about five times the amount of the sample than where it was only dipped once. One of the reasons that might have caused this is because there is bacteria almost everywhere. For this experiment the bacteria mostly came from the mouth but during the experiment bacteria might have gotten to the ranch sauce by accident. Another thing that might have caused these results is in which part of the sauce you dip the cotton swab in.

Does double dipping in a sauce spread germs? Have you ever double dipped? The purpose of this project was to see if double dipping infects sauce with bacteria. I chose to do the experiment because I wanted to see how gross it really is to double dip when you are sharing something with other people. I think if I double dip a chip into a bowl of ranch, then it will have three times more bacteria than the bowl of ranch where the chip was only dipped in once.

I had a volunteer dip a chip a certain amount of times in each of the small amounts of ranch, then I waited for five for the results to show. My hypothesis was correct, yes, the double dip petri dishes have more bacteria than the one where it was only dipped once. These results make sense, if your mouth is filled with bacteria, then it would probably transfer to the sauce.

The only part I didn’t predict right is how much bacteria there was. I think there might have been more bacteria than the amount I predicted. In the hypothesis I predicted there would be three times more bacteria in the double dip sample than the dipped once sample. I learned how to count bacterial colonies, and it turns out there's about four times the amount of bacteria in the petri dishes the chip was dipped more than once. This is only with a little bit of ranch which is about the amount of sauce in a fast food packet. Maybe the bacteria would minimize if I were to test with a bigger amount, but I'm not sure. I also think that it depends where you dip the cotton swab. If you dip it directly where the chip was double dipped it might have collected more bacteria than if you dip it in a part of the sauce where the germs didn't get to it.

The proof that I have for my results for this experiment are the videos and pictures I took during the duration of the experiment that are included in my data. The data I collected was the amount of bacteria in each of the dips; the petri dish I double dipped grew more bacteria than the dipped once and the dipped zero times.

Have you ever gone to a party, or gone to a restaurant with your family and friends where you are sharing a dipping food like strawberries and chocolate sauce, or ketchup with fries. Well I have, and sometimes I am not satisfied with the amount of sauce on the fry that I am eating once I've already bitten it. Should I dip it again? Well, you can but it's kind of nasty but you can flip the chip around to the side that has not been bitten.This could possibly minimize the amount of germs spread. This is how my experiment can affect real life situations. Maybe the next time you are going to double dip you might remember the results if this experiment.

Some people double dip in a sauce without knowing it could spread bacteria. Whether it is at a party or you are just having dinner. Grabbing the chip, dipping it once, and then biting it. Sometimes you are not satisfied with the amount of sauce on your chip. Should you dip it again?

Spangler,Jack. “Double Dip Chip Challenge.”stevespanglerscience.com, December 12, 2009, https://www.stevespanglerscience.com/lab/experiments/double-dip-chip-challenge/

Doyle,Mengan.“Does Double Dipping Really Spread Germs?” nz.education.com, April 2017, https://nz.education.com/science-fair/article/double-dipping/

Spangler,Steve. “Think Twice Before You Double-Dip That Chip-Petri Dish Tells It All” stevespanglerscience.com, December 12, 2009, https://www.stevespanglerscience.com/2009/12/16/think-twice-before-you-double-dip-that-chip-petri-dish-test-tells-all/

Spangler, Steve “Double Dip Chip- Cool Science Experiment” YouTube, uploaded by Sick Science! 16 December 2009, https://www.youtube.com/watch?v=Ws7K-dtX0nM

ACKNOWLEDGEMENTS