The 5-second rule

The 5-Second Rule Exposed: What You're Not Being Told

Written by: Vincent Pedre M.D. | June 1, 2024 | Time to read 17 min

A piece of perfectly edible pineapple falls on the floor. Do you pick it up and eat it? Or throw it in the trash? If you were at a party talking to someone and suddenly food dropped to the floor, both people’s eyes might wander to the floor and then look back at each other. The inner thought is, “Should I still eat it?” When you were a kid, you might have picked it up and eaten it immediately while laughing with your friends. As an adult, you might hesitate a bit more as your mind rapidly calculates the cleanliness of the floor it was dropped on (and when was the last time it was mopped?).

Many of us joke about the 5-second rule when it comes to food that has fallen on the floor. Pick it up in less than 5-seconds, and it's still good to eat. But is this rule backed by science, or is it just a myth?

Origins of the Five-Second Rule

The origins of the five-second rule are somewhat unclear, but it has been passed down through generations as a seemingly practical guideline. It's often used to justify eating food that has been dropped, especially when the floor looks clean or when wasting food feels wrong. I’m sure any of you reading this have at some point or another picked up a food item that fell on the floor and put it in your mouth. Hey, it may not be the worst thing you can put in your mouth, but actually pose some dangers.

Despite its widespread acceptance, the five-second rule has always been more of a cultural belief than a scientifically proven fact.

Scientific Studies on the Five-Second Rule

The true pioneer of five-second research was Jillian Clarke, a high-school intern at the University of Illinois in 2003. Ms. Clarke conducted a survey and found that slightly more than half of the men and 70 percent of the women knew of the five-second rule, and many said they followed it. She did an experiment in which she contaminated ceramic tiles with E. coli, placing gummy bears and cookies on the tiles, and then analyzing the foods.

Clarke's research found that food dropped on a contaminated surface can pick up bacteria almost instantly, debunking the idea that five seconds is a safe window.

Another significant study by researchers at Rutgers University, further examined how bacteria transfer from surfaces to food. Their findings revealed that bacterial transfer can begin in less than one second and that the amount of bacteria transferred increases with longer contact times. This transfer varies with the type of surface and food, with some foods showing higher transfer rates (Miranda & Schaffner, 2016).

Ok, so we could now say that not all transfers of bacteria from floor to food are equal. Some surfaces pose greater risks. And some foods are more likely to pick up bacteria than others.

Factors Affecting Bacterial Transfer

So here are the 3 main factors that affect how quickly and how much bacteria transfer from the floor to the food:

1. Type of Food

Types of food

Moisture is the Key: Transfer of bacteria from surfaces to food appears to be affected most by the moisture of the food. Foods with high moisture content, such as watermelon or sliced fruit, create an ideal environment for bacteria to thrive and transfer more readily. This is because moisture allows bacteria to move more freely and adhere more easily to the food's surface.

In contrast, dry foods like nuts, crackers or chips have lower transfer rates due to their lack of moisture, which inhibits bacterial movement and adhesion.

This phenomenon underscores the importance of considering the type of food when evaluating the safety of the five-second rule. Moist foods are particularly susceptible to contamination, even with minimal contact time. Therefore, it is crucial to be cautious and avoid consuming any moist food that has come into contact with potentially contaminated surfaces. So, that pineapple slice I mentioned earlier… probably better to chuck it than bite it!

2. Type of Surface

Types of surface

Surface Contact is a Major Factor: The type of surface on which the food falls significantly affects bacterial transfer rates. Research by Miranda and Schaffner (2016) highlights that carpet has lower transfer rates compared to tile and stainless steel. This is because carpets have a more complex surface structure, reducing direct contact with the food. On the other hand, smooth surfaces like tile and stainless steel allow for more efficient bacterial transfer. Wood surfaces present variable results due to their porous nature and varying cleanliness levels.

It's important to note that while carpets may have lower transfer rates, they can still harbor dust, allergens, and other contaminants that are not necessarily bacteria. These particles can adhere to food, posing different health risks. Thus, regardless of the surface, it is best to avoid eating food that has fallen on the floor.

But, if you’re eating at home and a cracker or nut falls on a wooden floor that you know is clean, then you might be able to hedge your bets and take that bite after all!

3. Contact Time

Types of surface

Time Matters, But Not That Much: While the five-second rule suggests a safe window of five seconds, research shows that bacteria can transfer in less than one second. However, the longer the food remains in contact with the contaminated surface, the more bacteria it is likely to pick up. Therefore, even a quick retrieval does not guarantee the food is free from harmful bacteria.

Speaking of, are you wondering what type of bacteria might be found on floors? And whether they could be harmful to your health or not? Let’s dive in and learn a little more about the hidden dangers of eating food from the floor.

Common Bacteria Found on Floors

Floors can harbor various types of bacteria, many of which can cause foodborne illnesses. Common bacteria found on floors include:

  • Escherichia coli (E. coli): Often found in areas with poor sanitation and can cause severe gastrointestinal illness.

  • Salmonella: Commonly associated with food poisoning, causing symptoms like diarrhea, fever, and abdominal cramps.

  • Staphylococcus aureus: Can cause a range of illnesses from minor skin infections to life-threatening diseases.

  • Enterobacter aerogenes: Commonly found in the environment, including soil, water, and on various surfaces, including floors.It primarily affects individuals with weakened immune systems or underlying health conditions. Symptoms often include fever, chills, and signs of the affected system (e.g., difficulty breathing for respiratory infections, or painful urination for urinary tract infections). It has shown resistance to multiple antibiotics, making infections difficult to treat. Longer contact time increases the chances of getting this bacteria. 

    These bacteria can be present even on seemingly clean floors, especially in high-traffic areas or where food is frequently prepared and consumed. Which floors are most at risk of contamination? Well, luckily, there was a study that looked at just that.


Where Are the Most Contaminated Places?

In a study that lasted 4 years, in four US cities, researchers studied the hygiene of over 1000 surfaces from various public places like shopping centers, daycare centers, and offices. They found biochemical markers of contamination, such as hemoglobin, amylase, and urea, on various surfaces. Children's playground equipment and daycare centers were among the most contaminated. Total and fecal coliforms were found on 20% and 7% of surfaces, respectively. Contamination from public surfaces often transferred to individuals' hands and personal belongings. Ew!

When scientists looked into the kitchen floor, often seen as one of the dirtiest spots, they found it had about 3 colonies per square inch of coliform bacteria. Surprisingly, that’s cleaner than the refrigerator handle (5.37 colonies per square inch) and the kitchen counter (5.75 colonies per square inch). And get this — the bathroom's flush handle had a whopping 34.65 colonies per square inch (yep, I’d be careful about flushing a public toilet), and the sink faucet had 15.84 colonies per square inch. And if you never wash or disinfect the kitchen sponge, it is likely to be the dirtiest thing in your kitchen, with over 20 million colonies per square inch.

Actually, there are countless studies showing that things we touch every day are so, so dirty— Gas pump handles , A.T.M. buttons , Remote controls ,  Light switches , Computer keyboards. Even money isn't safe! A study found that 94% of one-dollar bills had bacteria on them, with some of those being harmful to healthy people and even more dangerous to those with weakened immune systems.

Now, think about your phone screen. When was the last time you cleaned it? Our phones go everywhere with us, often touching our hands and faces more than anything else. It’s probably one of the dirtiest things we own, yet we rarely think to clean it regularly. So, next time you wipe down your countertops or wash your hands, don’t forget about giving your phone screen a disinfection, too!

All of this should remind you that it’s always a good idea to wash your hands before you eat. Hand-washing, but not sanitization, is still one of the best ways to prevent illness. I discuss the difference between the two, why hand-washing with soap is adequate, and why we should avoid anti-bacterial soaps and excessive use of hand sanitizers in my book, The GutSMART Protocol.

Practical Tips for Food Safety

To ensure food safety, it is essential to adopt practical measures in both home and public settings . Here are some tips to minimize the risk of foodborne illnesses:

  • Maintain Clean Surfaces: Regularly clean and sanitize surfaces where food is prepared and consumed to reduce bacterial presence.

  • Use Food-Safe Materials: Opt for food-safe materials, such as stainless steel or glass, for food preparation and storage to minimize contamination.

  • Practice Proper Hygiene: Wash hands thoroughly with plain soap (not antibacterial soaps) before handling food to prevent the transfer of bacteria from hands to food.

  • Be Cautious with Moist Foods: Avoid placing moist foods (like raw meats) directly on potentially contaminated surfaces, as they are more prone to bacterial transfer.

To maintain a healthy gut and reduce the risk of digestive issues, it's also essential to adopt good eating habits and consider adding dietary supplements that support gut health.

What’s the biggest gut health complaint worldwide? ... Bloating!

You don’t have to eat food picked up off the floor for your gut to be a mess. Most people with bloating are walking around with sluggish digestion and a leaky gut. That’s where the Bloat-Free Bundle comes in to address these underlying root problems behind bloating.

The Bloat Free Bundle [ Enhance + Activate Plus] offers a comprehensive solution for those looking to maintain a balanced and healthy digestive system. This bundle is designed to reduce bloating and improve overall gut function by supporting the integrity of the gut lining and enzyme production, helping you feel your best every day.

Why Activate Plus?

Activate Plus offers a powerful blend of enzymes and ox bile. It is specifically formulated to help break down a wide range of foods, including proteins, fats, and carbohydrates, which maximizes nutrient absorption while minimizing digestive discomfort. This supplement is particularly beneficial for those of you that suffer from bloating on a consistent basis or feel like your food takes forever to digest. Before indulging in a meal that might leave you feeling sluggish and bloated, take one capsule of Activate Plus for a happy gut, no matter what you throw in it. With the inclusion of Betaine HCl, Activate Plus helps reduce gas and bloating, promoting the digestion of proteins quickly and easily, thus ensuring a smoother digestive process.

Why Enhance?

Enhance works in synergy with Activate Plus by focusing on optimizing your gut lining. ENHANCE is a comprehensive gut healing powder that contains 14 doctor-backed, well-researched nutrients to support optimal gastrointestinal health and function. It helps to repair the gut lining, promote regular bowel movements, improve nutrient absorption, support immune function, and reduce bloating and gas. It’s a safe and effective way to improve your gut health and overall well-being.

Together in the Bloat-Free Bundle, Activate Plus and Enhance form a dynamic duo that tackles common digestive issues from two angles: enhancing enzyme production and supporting a healthy gut lining. This combination allows you to enjoy meals without worrying about discomfort and feel great overall.

To explore the full benefits of the combo visit the Bloat Free Bundle.

Debunking the 5-Second Rule Myth

The five-second rule is a widely held belief that has been debunked by scientific research. Bacterial transfer can occur almost instantaneously when food touches a contaminated surface (such as the floor), and various factors such as surface type, food moisture, and environmental cleanliness play critical roles in this process.

To ensure food safety and protect your gut, it’s probably best to discard any food that has fallen on the floor and adopt proper hygiene and sanitation practices.

By understanding the science behind bacterial food transfers and the limitations of the five-second rule, you can make informed decisions about food safety and minimize the risk of foodborne illnesses. Ultimately, the best approach is to prioritize cleanliness and caution when handling and consuming food.


What is the five-second rule?

The five-second rule is a common belief that food dropped on the floor is safe to eat if picked up within five seconds.

Is the five-second rule scientifically valid?

No, scientific research shows that bacterial transfer can occur almost instantly, disproving the five-second rule.

What factors affect bacterial transfer to food?

Factors include the type of surface, food moisture, and contact time.

Are certain foods more prone to bacterial transfer?

Yes, moist foods like watermelon and fruit have higher transfer rates compared to dry foods.

Does the cleanliness of the floor matter?

Yes, floors that are not regularly cleaned can harbor more harmful bacteria.

What types of bacteria are commonly found on floors?

Common bacteria include E. coli, Salmonella, Staphylococcus aureus, and Enterobacter aerogenes.

Is it safer to eat food dropped on carpet than on tile?

Carpet has lower bacterial transfer rates, but it can still harbor dust and allergens that you may want to avoid.

How does moisture affect bacterial transfer?

Moisture facilitates faster bacterial transfer by allowing bacteria to move more freely.

What should I do if I drop food on the floor?

It is best to discard the food to avoid potential health risks.

Are there any exceptions to the five-second rule?

No, bacterial transfer can occur instantly regardless of the contact time.

Can I wash food that has fallen on the floor?

Washing may not remove all contaminants, so it is safer to discard the food.

Is it safe to eat food dropped outside?

No, outdoor surfaces can have more contaminants and bacteria.

What are the health risks of eating contaminated food?

Health risks include foodborne illnesses caused by bacteria like E. coli and Salmonella.

Can bacteria survive on dry surfaces?

Yes, bacteria can survive on dry surfaces and transfer to food.

Are children more susceptible to foodborne illnesses?

Yes, children have weaker immune systems and are more vulnerable to contamination.

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