By Dr. Mercola
The five-second rule posits that if you drop a piece of food on the floor and pick it up fast enough – say within five seconds of it touching the floor – it’s still safe to eat. This “rule” has been uttered by schoolchildren and, admit it, adults for decades – maybe longer – but is it really true?
On the most basic level, no. Bacteria can transfer to a surface almost instantly. So if you drop a piece of food on a contaminated floor (and virtually every floor is going to be covered in bacteria), it’s most likely going to pick up some bacteria.
How much bacteria, what types, and whether it’s enough to make you sick is the real question, and this varies depending on a number of factors…
Foods Pick Up More Bacteria from Smooth Surfaces Than Carpets
High-school student Jillian Clarke is often credited with doing the first scientific investigation of the 5-second rule, as part of an apprenticeship in a University of Illinois laboratory.
She noted that people have been pondering this question for ages, dating back to the era of Genghis Kahn, who reportedly believed food remained safe if it had been on the floor for 12 hours.
To find out the truth, Clarke inoculated smooth and rough tiles with E. coli then placed either cookies or gummy bears on the tiles for 5 seconds or less. The bacteria did transfer to the foods; however the gummy bears picked up more E. coli from the smooth tiles than from the rough ones.1
Research published in the Journal of Applied Microbiology found similar results. Researchers contaminated wood, tile, and carpeted surfaces with salmonella then dropped bologna or bread onto them for 5, 30, or 60 seconds.
In this case, the extra time spent on the floor didn’t impact how much bacteria the food accumulated.
Rather, it was the type of floor that mattered, with the hard surfaces transferring far more bacteria. In fact, bologna dropped onto tile or wood picked up 5 percent to 68 percent of the bacteria while bologna dropped onto carpet picked up less than 0.5 percent.2
And in the case of the tile, almost all of the bacteria transfer (more than 99 percent) occurred after just 5 seconds of exposure. What else impacted bacterial transfer was how much bacteria was on the surface (higher levels led to greater contamination). The researchers concluded:
“Salmonella Typhimurium can survive for up to 4 weeks on dry surfaces in high-enough populations to be transferred to foods and… S. Typhimurium can be transferred to the foods tested almost immediately on contact…
This study demonstrated the ability of bacteria to survive and cross-contaminate other foods even after long periods of time on dry surfaces, thus reinforcing the importance of sanitation on food contact to minimize the risk of foodborne illness.”
Some Research Suggests Picking Food Up Faster Might Reduce How Much Bacteria It Collects
While the aforementioned study found bacteria accumulate on a food almost as soon as it touches the floor, there is some research suggesting longer periods of exposure are worse.
Research conducted by researchers at Aston University’s School of Life and Health Sciences monitored the transfer of E. coli and Staphylococcus aureus from carpet, laminated, and tiled floor surfaces to a variety of foods (toast, pasta, cookie, and a sticky sweet).
This study, which has not yet been peer reviewed, concluded that time is a significant factor in the transfer of bacteria from a floor surface to a piece of food. Food left in contact with the floor for just 3 seconds picked up less bacteria than that left on the floor for 30 seconds.
The floor surface also made a difference in this study, with carpeted surfaces again transferring less bacteria than smooth laminate or tiled surfaces. Further, moist foods picked up more bacteria than dry foods.3
Certain Types of Food Pick Up More Bacteria Than Others
In addition to the type of floor surface, level of contamination, and length of exposure, another factor that influences bacterial transfer is the type of food itself.
Researchers from Manchester Metropolitan University (MMU) tested five types of food (bread with jam, cooked pasta, ham, a cookie, and dried fruit) that were dropped on the floor and left for 3, 5, or 10 seconds.4
In general, processed foods – those with high salt or sugar content – picked up less bacteria. This included the ham and the bread with jam, which had surprisingly little bacterial growth after touching the floor for three seconds.
The cookie, with its low water content, also showed little bacterial transfer, even after 10 seconds of exposure. The dried fruit and pasta, on the other hand, picked up klebsiella bacteria after just three seconds.
So Should You Eat Food That’s Dropped on the Floor?
The majority (87 percent) of people asked said they either have eaten or would eat food dropped on the floor.5 It’s a theoretical risk, but if you’re healthy it’s probably not going to make you sick.
There is a possibility that it could, however, so you’ll have to decide whether the piece of food is worth the risk… Paul Dawson of Clemson University, who co-authored the Journal of Applied Microbiology study mentioned above, explained further:6
“From a food safety standpoint, if you have millions or more cells on a surface, 0.1 percent is still enough to make you sick. Also, certain types of bacteria are extremely virulent, and it takes only a small amount to make you sick.
For example, 10 cells or less of an especially virulent strain of E. coli can cause severe illness and death in people with compromised immune systems. But the chance of these bacteria being on most surfaces is very low.
… Hands, foods, and utensils can carry individual bacterial cells, colonies of cells, or cells living in communities contained within a protective film that provide protection. These microscopic layers of deposits containing bacteria are known as biofilms and they are found on most surfaces and objects.
Biofilm communities can harbor bacteria longer and are very difficult to clean. Bacteria in these communities also have an enhanced resistance to sanitizers and antibiotics compared to bacteria living on their own. So the next time you consider eating dropped food, the odds are in your favor that you can eat that morsel and not get sick.
But in the rare chance that there is a microorganism that can make you sick on the exact spot where the food dropped, you can be fairly sure the bug is on the food you are about to put in your mouth. Research (and common sense) tell us that the best thing to do is to keep your hands, utensils and other surfaces clean.”
Your Food Might Contain Disease-Causing Bacteria Even Before You Drop It…
Worrying about what bacteria your chicken breast picked up after falling to the floor is a moot point to some extent if it’s already heavily contaminated. And if it’s typical store-bought CAFO (concentrated animal feeding operation) chicken, there’s a good chance it is. In the US, the structure of the food-safety system is inherently flawed and in need of overhaul.
A certain level of contamination is allowed in your food (and it’s more than you probably think). The salmonella “performance standard” for ground chicken, for instance, is 44.6 percent (and ground turkey is 49.9 percent). This means that nearly half of the ground chicken and ground turkey you buy can be contaminated with salmonella, and that’s fine and legal according to the US government.
If you think that’s bad, cut-up chicken parts have no performance standard at all, which means every piece of cut-up chicken you buy from a supermarket might be contaminated with salmonella (and it’s not just chicken – your lamb chops or pork ribs also might be 100 percent contaminated).
Now, salmonella is usually a self-limiting illness, but it’s not always. In 2013, a nationwide salmonella outbreak occurred, courtesy of infected chicken originating from Foster Farms.
The antibiotic-resistant strain of salmonella, known as Heidelberg, sickened close to 300 people in 17 states. Of those infected, 40 percent required hospitalization — twice as many people as typically require hospitalization due to regular salmonella.7
This is frustrating on multiple levels. First, the reason why we’re seeing antibiotic-resistant superbugs showing up in our food is largely the fault of the food industry itself. They’ve created this monster.
Animals are often fed antibiotics at low doses for disease prevention and growth promotion (agricultural usage accounts for about 80 percent of all antibiotic use in the US), and those antibiotics are transferred to you via meat, and even through the animal manure that is used as crop fertilizer.
Millions Are Sickened from Eating Food Each Year… How to Avoid Becoming One of Them
Twenty-two percent of antibiotic-resistant illness in humans is, in fact, linked to food – this is according to US Centers for Disease Control and Prevention (CDC) own data.8 So keep in mind that it’s not only food that’s dropped on the floor that could pose a risk of foodborne illness; much of the food you purchase at a typical grocery store comes into your home already contaminated.
Of the 9 million people who get sick from eating food each year, 55,000 are hospitalized and 1,000 will die.9 These are the estimates from the Interagency Food Safety Analytics Collaboration (IFSAC), which are actually far lower than those given by the US Centers for Disease Control and Prevention (CDC) in 2011.
According to those estimates, the problem is far worse with 48 million people being sickened by foodborne diseases each year, including 128,000 hospitalizations and 3,000 deaths.10 According to the IFSAC, certain foods cause so many illnesses each year that shopping at your supermarket is like playing a game of Russian roulette. It's possible to get sick from eating a cheeseburger, a bowl of salad, or a slice of cantaloupe.
Food safety is, I believe, just one of many reasons to opt for locally produced foods rather than CAFO brands sold in grocery stores. Besides safety, organic, grass-fed, and finished meat, raised without antibiotics and other growth-promoting drugs is really the only type of meat that is healthy to eat, in my view. The following organizations can help you locate healthy farm-fresh foods in your local area that has been raised in a humane and sustainable manner:
- Local Harvest – This Website will help you find farmers' markets, family farms, and other sources of sustainably grown food in your area where you can buy produce, grass-fed meats, and many other goodies.
- Eat Wild – With more than 1,400 pasture-based farms, Eatwild's Directory of Farms is one of the most comprehensive sources for grass-fed meat and dairy products in the United States and Canada.
- Farmers' Markets – A national listing of farmers' markets.
- Eat Well Guide: Wherever you are, Eat Well – The Guide is a free online directory of more than 25,000 restaurants, farms, stores, farmers' markets, CSAs, and other sources of local, sustainably produced food throughout the US.
- FoodRoutes – The FoodRoutes "Find Good Food" map can help you connect with local farmers to find the freshest, tastiest food possible. On their interactive map, you can find a listing for local farmers, CSAs, and markets near you.
Aside from purchasing your food from high-quality, small-scale sources, the best way to protect yourself from a food-borne infection (whether you believe in the 5-second rule or not) is to strengthen your immune system. This is ideally done through daily lifestyle choices that support your overall health, such as:
Avoiding sugar – especially fructose – grains, and processed food, and eating plenty of organic raw foods Getting adequate restorative sleep Finding a way to diffuse the stress life throws at you (my favorite tool is EFT) Incorporating regular exercise and non-exercise movement into your day Optimizing your vitamin D through sun exposure, a high-quality tanning bed or supplementation, if needed Eating fermented foods or taking a high-quality probiotic, which will help populate your gastrointestinal tract with beneficial bacteria — your best defense against bad bacteria like salmonella