Five-Second Rule?

We all know that moment when you drop a piece of food on the floor and have to make the quick decision of whether you want to eat it or not. Is the five-second rule really safe? Are we putting ourselves at risk of getting sick? I’ll admit that I have eaten food that I’ve dropped on the floor, which is why I wanted to look into the effectiveness of the five-second rule.

I first looked into some basic statistics about bacteria. The Centers for Disease control found that food contamination, from being dropped on the ground, was the 6th most common factor for food poisoning out of 32 outbreaks. Further, a study done in 2015 stated that out of the 9,000 01-five-second-rule-food-adapt-590-1types of microscopic organisms in our homes, 7,000 are mostly harmless bacteria. Bacteria is everywhere, even if we don’t realize it; researchers found that we release 38 million bacteria cells into the atmosphere every hour. Although most bacteria in our homes are harmless and can help us develop a stronger immune system, is it still two risky to eat food that has fallen on the ground?

I found a couple studies that explored the question of the degree that different foods are contaminated across different confounding variables: the surface of the ground, the moisture of the food and time.

The first experiment was performed in 2007 by Paul Dawson, which studied the survival time and contamination of Salmonella Typhimurium to sausage and bread using wood, tile, and carpet. The study concluded that 99% of the bacteria contaminated the sausage after 5secs on the tile. When compared to the wood and tile the sausage was contaminated less than 0.5% when it was dropped on the carpet. It was also concluded that the survival time for Salmonella Typhimurium is up to 4 weeks on dry surfaces and is in high enough populations to immediately contaminate food when dropped.

A second two year experiment was conducted by Donald W. Schaffner, a food microbiologist at Rutgers University, and Robyn C. Miranda, master’s thesis student, that 00xp-fivesecondrule-master768evaluated different contact times using 4 different surfaces (stainless steel, ceramic tile, wood and carpet) and foods (watermelon, bread, buttered bread, strawberry gummy candy). The foods were dropped from 5in onto each surface which was pre contaminated with a bacteria like salmonella. The study used 4 different contact times(amount of time it took the food to hit the surface). The trials were replicated 20 times each, which gave 2,560 results. The experiment concluded that there was a direct relationship between the time food was left on the ground and the amount of bacteria that transferred. The carpet had the lowest transmission rate out of the 4 surfaces. Also foods that had more moisture collected more bacteria; the watermelon was contaminated the most and the gummy candy the least. Since the study was large and evaluated multiple confounding variables it can be concluded that bacteria contaminates food instantaneously.

Both studies agree that food is contaminated immediately when it is dropped on the floor. However, the longer the food remains on the surface and the moisture of the food are factors that can lead to more, or less transferred bacteria. Therefore, the five-second rule is up for you to decide. The evidence proves that your food will be contaminated, however, there have not been studies to prove if the amount of bacteria that transfers is enough to make you sick. In this article the scientists who performed these experiments discuss whether or not they follow the five second rule. They all have mixed opinions and it comes down to personal preference. I know that after reading about how quickly bacteria contaminates food I’m going to think twice before eating something I’ve dropped on the ground.

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10 thoughts on “Five-Second Rule?

  1. Thomas Tatem Moore

    This article really caught my eye due to the fact that it is very relatable because of how often the five second rule is mentioned. Many times when I drop a piece of food it is not long before someone around me mentions the rule. While I never really believed in the five second rule because I always thought “what can five seconds really do to a piece of food”? This article confirmed my opinion but you really do never know what is on the floor you dropped the food on. Here is an article that describes many aspects of the five second rule myth.

  2. Matthew J Overmoyer

    These experiments seem ridiculously simple. I’m surprised no one studied this earlier. Checking to see if food was contaminated greatly by contact with the floor is something we’ve all thought about before eating it anyway. I think something important to consider when eating something off the floor is the cleanliness of the surface. It is obvious that food will be contaminated by coming into contact with bacteria, but limiting that bacteria would make it safer. Like, being in your apartment and picking something off the floor is probably way safer than picking something off the ground outside. I also found it interesting how thorough this study was: with different surfaces, wetness, and different foods picking up more or less bacteria.

  3. Nathan Andrew Morningstar

    Text overlapping made it really difficult to read the beginning of the article. For me, I never believed in the five second rule, only because I would think about all of the surfaces that everyone might have walked on or the muck that might be on the floor.

  4. Liz Galante

    Since I am younger I always have been a big germaphobe and never trusted the 5 second rule but after learning and reading about all the statistics you used to prove that the 5 second rule isn’t considered to be necessarily unhealthy I look at it a different way. It is evident that it could cause you to get germs from wherever it has fallen but when you think about it, what is 5 seconds going to really do to you? Then again, you never know.

  5. Madelyn Erin Peikin

    This post is extremely relatable. I think pretty much everyone who drops food on the ground screams “five second rule!” right after and eats it anyway (myself included). I had no idea how much bacteria can catch from just dropping your food on the ground for a short amount of time! Here is a video I found interesting on the five second rule if you haven’t already come across it. I looked into it after reading this article and every article says to be careful and abandon the five second rule. Thanks for sharing!

  6. Christina Rae Locurto

    Great blog post with fantastic statistics and data to back up your facts. I do think the “5 second rule” can in fact contract germs, but the number is so small that the diseases you might catch will not even be that deadly. Unless you drop a piece of food directly onto a pile of garbage or something like that, chances are you won’t even get sick. Because of the infinite number of surfaces you could drop food on, each case will be slightly different. I would say the surface you drop food on is the biggest and most significant confounding variable, but others can include the person’s immune system, age, sex and environment a person grows up in.

  7. Ryan Gregory Blank

    Apparently you can disregard anything I just said about text overlapping pictures because as soon as I posted that comment, everything corrected itself. Great job on the blog!

  8. Ryan Gregory Blank

    Can the 5 second rule still count if you brush it off? I am guilty of following the 5 second rule but likely I have not gotten terribly sick from it. This is a very interesting study and I enjoyed your topic and information, but I must admit it is very hard to read with long urls embedded into the sentence and text overlapping pictures. By no means does that make your blog bad, just a little hard to read and comprehend in some areas.

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