Forget The Five-Second Rule!


Do you believe that food is safe to eat if you snatch it up from the floor within five seconds of dropping it? Sorry, you’re wrong … and you have probably consumed a whole lot of bacteria.

Researchers continue to debunk the so-called “5-second rule” – that food dropped on the floor, but picked up quickly, is safe to eat because bacteria need time to transfer – but somehow clumsy eaters and the frugal-hungry folks among us keep thinking that contamination can be avoided with fast action and good reflexes.

But when it comes to a speed test between bacteria and you, bacteria is going to win the battle.

Rutgers researchers decided to subject the 5-second rule to the rigors of scientific testing. Donald Schaffner, professor and extension specialist in food science, and his team found that moisture, the type of surface and contact time all contribute to cross-contamination. In some instances, the transfer begins in less than one second.

Schaffner noted that while the pop culture “5 second rule” has been debunked by at least two TV programs, scientific research in peer-reviewed journals on the topic is limited.

“We decided to look into this because the practice is so widespread. The topic might appear ‘light’, but we wanted our results backed by solid science,” Schaffner explained

Go, Bacteria, Go

The Rutgers team chose four different types of surface – stainless steel, ceramic tile, wood, and carpet. They also grew Enterobacter aerogenes – a nonpathogenic relative of Salmonella that is naturally occurring in the human digestive system – and inoculated the test surfaces with the bacteria. The surfaces were allowed to completely dry before food samples were dropped onto them

They team selected a four different foods to test; watermelon, dry bread, bread spread with butter, and gummy candies. Each piece of food was then dropped on each bacteria-covered surface, and left there for various amounts of time: 1 second, 5 seconds, 30 seconds, and 300 seconds.

A total of 128 different scenarios trials were completed and replicated 20 times, adding up to 2,560 individual measurements that were used to analyze the amount of contamination on each food item.

Which food was bacteria’s favorite? You might be guessing the buttered bread or sticky candy – but it was the watermelon. Gummy candy was consistently the least contaminated food in the test.

“Transfer of bacteria from surfaces to food appears to be affected most by moisture,” Schaffner said. “Bacteria don’t have legs, they move with the moisture, and the wetter the food, the higher the risk of transfer.”

And you might think that carpet – given its tendency to gather dust, dirt, assorted crud and crumbs –would contaminate food very quickly, but no. The rough structure of carpet actually minimizes the amount of contact the surface – and lurking bacteria – has with the food. Tile and stainless steel had the highest rates of transfer, while wood was variable. Considering that surfaces in medical settings tend to be smooth, for easy cleanup, this was an interesting finding.


But overall, no matter what the surface, longer food contact times did result in the transfer of more bacteria from each surface to food. So while the researchers demonstrate that the five-second rule is “real” in the sense that longer contact time results in more bacterial transfer, it also shows other factors, including the nature of the food and the surface it falls on, are of equal or greater importance.

“The 5-second rule is a significant oversimplification of what actually happens when bacteria transfer from a surface to food,” Schaffner said. “Bacteria can contaminate instantaneously.”

Safe Eating

Annually, about 76 million people in the United States become ill from the food they eat, and about 5,000 of them die, according to the Centers for Disease Control and Prevention. The vast majority of these people were not sickened by food they dropped on the floor and picked up, but by food they purchased that was contaminated or by mishandling food that they prepared at home.

The most common foodborne illnesses are norovirus, Salmonella, Clostridium perfringens, and Campylobacter. Symptoms of food poisoning can be as commonplace as diarrhea and stomach cramps or as severe as organ failure. Food borne illnesses can cause long-term health problems or death. When young children, pregnant women, older adults, and people with weak immune systems are particularly at risk.

The CDC recommends you see your doctor or healthcare provider if you have “diarrhea along with a high fever (temperature over 101.5°F, measured orally), blood in the stools, prolonged vomiting that prevents you from keeping liquids down, signs of dehydration, including a decrease in urination, a dry mouth and throat, and feeling dizzy when standing up, or if you have had diarrhea for more than 3 days.”

Unsure whether that upset stomach is something to be worried about? Consider checking in with a doctor or nurse by phone or videochat to discuss your symptoms. The most affordable way to do this is by joining a telemedicine plan that offers free consultations with local doctors 24/7,  along with access to a broad range of medical experts who can provide insight on virtually any health or wellness issue. With telemedicine, you may be able to skip the doctor’s office, the emergency room or the urgent care clinic and still get the care you need – including prescriptions – for many common ailments.

Click here for more details on affordable, comprehensive telemedicine plans, or call the :DentalPlans’ AtYourService team at 866-552-7563.


Join. Save. Smile.