Live Healthy Live Well

Do you follow the “5-second rule” when you drop food on the floor?  If you do, you may want to rethink your actions.

Different factors affect how quickly bacteria will be transferred.  These
include moisture, type of surface, and contact time.  It was found in some instances the bacteria began to transfer in less than one second.  Time to rethink the idea that you can pick up any food off the floor quickly, and it is safe to eat.

Researchers at Rutgers University tested four surfaces:

• stainless steel
• ceramic
• tile
• wood

Each of the surfaces were contaminated an Enterobacter aerogenes, “cousin” of Salmonella.  The bacteria were allowed to dry before food was dropped.

They used four different types of foods:

• watermelon
• bread
• bread and butter
• gummy candy

The researchers replicated the scenarios 20 times each checking the bacteria transfer to food samples at less than one second, five, 30 and 300 seconds.  Each food sample was then analyzed for contamination.

Moisture seemed to increase the transfer of bacteria to food the most.  Watermelon contained the most contamination while gummy candy contained the least.  The longer the food was on the contaminated surface the more bacteria it contained. However, contamination from bacteria can occur instantly. 

Surprisingly, carpet had low transfer rates. Tile and stainless steel had higher transfer rates than wood which was variable.  Another study with tile found E. coli was transferred to gummy candy in less than 5 seconds with more bacteria transferred from smooth tile than rough tile. 

Next time, you drop some food on the floor you may want to think twice before you put it in your mouth.  Any food that has been on the floor may contain bacteria which may make you sick.  Is the food that important or expensive?   Would you be better off throwing it away?   It is always better to avoid infection or being sick.

Author:  Pat Brinkman, Extension Educator Family and Consumer Sciences, Ohio State University Extension

Reviewer: Shannon Carter, Extension Educator, Family and Consumer Sciences, Ohio State University Extension, Fairfield County

References:

Aston University. (2014). Researchers Prove the Five Second Rule is Real. Aston University’s School of Life and Health Sciences.  Available at http://www.aston.ac.uk/news/releases/2014/march/five-second-food-rule-does-exist/

Schaffner, D. (2016). Rutgers Researchers Debunk ‘Five-Second Rule’: Eating Food off the Floor Isn’t Safe.  Rutgers Today.  Available at http://news.rutgers.edu/research-news/rutgers-researchers-debunk-%E2%80%98five-second-rule%E2%80%99-eating-food-floor-isn%E2%80%99t-safe/20160908#.V_ZUJvkrKUk

University of Illinois at Urbana-Champaign. (2003). If You Drop It, Should You Eat It?  Scientists Weigh In on the 5-Second Rule.  College News.   Available at http://news.aces.illinois.edu/news/If-you-drop-it-should-you-eat-it-scientists-weigh-5-second-rule