Is the 5-second rule reasonable?

When a bite of something hits the floor, do you pick it up and eat it? For many of us, it depends on what it is and where it falls. If it’s a piece of candy, especially chocolate, I might think about it. If it’s something mushy and soft, not a chance because at my house the food would be covered in dog hair and germs. 

Many times we declare the 5-second rule thinking there’s no way germs can infect our tasty morsel so quickly. But according to research, that’s generally not the case. 

Ruth Frechman, a registered dietitian with the American Dietetic Association, says “Bacteria are all over the place, and 10 types, including E. coli, cause foodborne illnesses, such as fever, diarrhea and flu-like symptoms.”

When Meredith Agle was a doctoral candidate at the University of Illinois she supervised a study on the “5-second rule.” Later, as a scientist in new product development, she determined — based on her research and experience — floor type and moisture content of the food determine the safeness of the “5-second rule.”

She found that on smooth, dry surfaces like hardwood or granite that were cleaned regularly, “most pathogens like salmonella, listeria or E. coli can’t survive without moisture.” But in a controlled study using cookies and gummy bears placed on both rough and smooth tiles covered in E. coli, they saw a transfer of germs before 5 seconds. 

According to the Centers for Disease Control and Prevention’s National Center for Infectious Diseases, an estimated 76 million Americans contract foodborne illnesses every year. Of them, 300,000 are hospitalized and 5,000 die because of these illnesses. Generally it’s the youngest, oldest and those with weakened immune systems who die from foodborne illness. 

Agle admits she still might pick up food off the floor but says she’s not in the susceptible population. Her take-home message: “If there are microorganisms present, they will transfer in less than the five seconds.” 

So how lucky and how healthy are you? Think about that the next time you declare the 5-second rule!