5-Second Rule

No matter where I am, or what the food is, I will never eat anything that touches the ground. To be completely honest, I am what someone could consider as a germaphobe. With this being said, the other day I noticed a friend of mine eat a goldfish that had previously been on the ground. His reasoning was that since the goldfish was only on the ground for a minimal amount of time, it was still in a condition in which it is safe to consume. This is more commonly known as the 5-second rule. This phenomenon establishes the idea that if food is on the ground for less than 5 seconds, it is still sanitary enough to eat. It has been on my mind for weeks now, and I have decided to discover the truth. I need to know if someone can grab their fallen food within 5 seconds, is the freshness/cleanliness of the food preserved, or will it become germ-ridden?


To start to answer this question, we must determine what affects the transferring of germs. This article states that moist food is more susceptible to picking up germs. It also goes on to say that certain surfaces are going to transfer more germs than others. For example, a carpeted surface is going to spread fewer germs, than a stainless steel surface, or a tiled surface. Next step is to find a well-conducted experiment. To prove that the 5-second rule is true, we must find a study that obtained results displaying that before the 5-second mark, little to no germs were transferred to the food. If any other result comes from the experiments, then we will know that the rule is invalid and just another myth. Also, the experiment must be conducted in a manner in which it has next to no confounding variables, and contains a large enough sample size to further convince us the results pertains to almost every situation.

I found a study that put this myth to the test. It was an experimental study, and the findings were impressive enough for those involved to receive an IG Nobel Prize. This experiment was conducted by a high school student (Jillian Clarke), on a six-week internship at the University of Illinois. Along for the ride was a doctoral candidate to supervise the study. They wanted to test how many germs are transferred over a specific amount of time and discover the validity of the 5-second rule. The null hypothesis for this experiment was that before the 5-second mark, no germs would spread. The alternative hypothesis was that before the 5-second mark, germs would have spread to the food. If the null hypothesis is correct, the 5-second rule would be proven true.

First, Jillian Clarke measured the amount of e-Coli that was present on both a rough, and smooth surface. This provided a base for the amount of germs initially present, and the variety of surfaces was done to eliminate a possible third confounding variable from the experiment. Next, she placed a cookie, and a gummy bear on both surfaces, and observed and recorded her results. She found that germs started to transfer even before the 5-second mark. The results supported the alternative hypothesis and showed that the 5-second rule was just a myth. The results suggested that a short amount of time does not preserve the sanitation of food (At least in the case of gummy bears, and cookies).




This experiment has taught me that the old 5-second rule is just a myth. In fact, germs start to transfer to the food the second it touches the floor. I was expecting the learn that this rule was established from scientific proof, but I discovered that this rule is just another example of widely accepted theory not backed by any scientific evidence. I believe that the experiment was conducted in a manner to provide sufficient data to make the firm inference that the 5-second rule is incorrect. They attempted to rid the experiment of third confounding variables, and the sample size was large enough to produce convincing results. With that being said, the experiment was recognized and accepted enough to merit an IG Nobel Prize.

The most important concept anyone can take from this experiment is that germs spread at a faster pace than most realize. Being careful with tainted surfaces, and recognizing the fast paste at which germs spread, can help prevent the transferring of food born illnesses. This can help keep people safe from contracting an avoidable ailment.









5 thoughts on “5-Second Rule

  1. Emma Murphy

    I am a big “5-second rule” follower, so this post was definitely eye opening for me. Last year when I heard that there was an e. coli breakout in Qdoba and Chipotle, I avoided both of my local mexican restaurants for a while. It was crazy to read about how by following the 5-second rule I was possibly exposing myself to the same e. coli breakout as these local restaurants because of its ability to be present on a rough and smooth surface. After reading your post I am definitely going to stop eating an fallen food off the floor. http://www.foodbeast.com/news/qdoba-typhoid/

  2. Alexander Roker

    This is a very interesting post because as someone commented above, I have always wondered why five seconds is the time period of choice. As far as I can tell, five was chosen almost out of convenience. An article I found shows that germ accumulation is progressive, so five seconds is better than fifty seconds, for example. But, studies have shown that in just five seconds germ build up is still substantial. Here is the article: http://www.nytimes.com/2016/09/20/science/five-second-rule.html?_r=0

  3. rlw5445

    This post truly forced me to take a step back and question a widely accepted behavior in the world. I am sure if you ask anyone they could not tell you the origin of the 5-second rule or provide any substantial evidence that it does in fact work. We are so eager to accept something as truth without actually looking at the facts and data. People have been picking food up off the floor for generations without questioning the possible impacts. Upon some research I discovered that the origin of this saying was founded in contemporary folk wisdom, and in fact relied on no data or evidence at all. If you wish to learn more about the origins visit this website http://www.snopes.com/food/tainted/dropped.asp.

  4. Delaney Ann Flynn

    Personally, I am not a germaphobe at all. I was an avidly believer in the 5-second rule and now I see that maybe it isn’t the best idea to put stock in every old wive’s tale that circulates. I was always suspicious as to why exactly 5 seconds was the safety mark, and that suspicion should have carried over to questioning the idea as whole. Web MD investigates further and finds that the rule in applicable in some cases- so maybe there’s hope for the 5 second believers.

    Web MD

  5. Catherine Drinker

    This is something I have noticed a lot too with teenagers who simply do not care and just use the “5-second rule” as an excuse to put something they want to eat into their body. I did some research though and the less time the better. But by no means is 5 seconds a period where no germs get attached to the food. http://kidshealth.org/en/kids/5-seconds.html

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