The Truth About the 5-Second Rule
Last Sunday morning I was in a really good mood. For those of us in Australia, it was the first day of summer. The warmth of the sun was creeping through the window, smothering the kitchen in morning sunlight.
But that’s not why I was in a good mood. To be honest, I was just excited to sink my teeth into a vegemite and melted cheese sandwich — my delicious weekend breakfast.
As I was slicing a block of cheese, a small, deliciously bite-sized piece fell to the floor. Despairingly (thanks to what many would call an ‘obsession’ over not wasting food) I quickly grabbed the no-longer-worthy-of-my-sandwich cheese off the floor. I was just about to put it in my mouth, calling the “five-second rule” as my defense, when I stopped mid-bite. Is this cheese actually still clean and safe to eat, I wondered. Surely bacteria has already infested, considering hair and dust manage to stick to cheese in an instant. It got me thinking, just how many people would eat this bit of cheese. Would you have eaten it?
The Infamous Five-Second Rule
The five-second rule, the alleged time in which it takes bacteria to attach to your dropped cookie, is no strange phenomenon, having appeared on popular TV shows such as Grey‘s Anatomy, The Simpsons and How I Met Your Mother. It’s a world-wide term that seems to get manipulated and abused often; I’m sure I’ve even heard someone claim ’the 5-minute rule’ once or twice before.
But is there any validity to the so-called five-second rule?
Perhaps it’s effective in social situations where you want it to seem somewhat acceptable to your peers that you’re eating food off the ground. However, from a scientific standpoint, no, the five-second rule is false. (And yes, some researchers actually managed to get funding to conduct research on this).
The first study was conducted in 2003 by a professor and her intern, Jillian Clarke, at the University of Illinois. Clarke placed food on E. coli-laden tiles for five seconds or less to test contamination levels. The foods used for the experiment were gummi-bears and fudge-striped cookies; customers reportedly value these foods more highly, thus making them more likely to be retrieved off the floor. Seriously.
In all cases, E. coli was transferred to the food in five seconds or less. (Clarke also found in surveys that women were more likely than men to eat food that’s been on the floor.)
In 2006 a more systematic study investigating how salmonella behaves on wood, tiles and nylon carpet found that after eight hours of exposure, the bacteria could still contaminate many foods in under five seconds. One minute or more of contact increased contamination tenfold on tile and carpet surfaces. Lead researcher Professor Paul Dawson concluded, “Salmonella Typhimurium can survive for up to 4 weeks on dry surfaces in high-enough populations to be transferred to foods and Salmonella Typhimurium can be transferred to the foods tested almost immediately on contact.”
Other Nasty Stuff on Your Floor (Think Fecal)
Robert Romaine, a San Diego County health inspector for 25 years and food safety consult, told WebMD, “We teach students that any surface, especially floors, should not be considered clean, and any food that comes in contact with it is trash.”
That includes counters that have been washed and sanitized. “Consider the potential for damp floors and what might be on the shoes of a worker who walked her dog or used the restroom before coming to work. Then someone lifts a carton of produce from the floor and sets it on the counter.”
The one thing that really caught my attention there is the word ‘restroom.’ Now the floor around public toilets is NOT clean — I don’t care how much bleach was used. You certainly don’t want bacteria from public restrooms anywhere near your face, let alone in your mouth.
Thanks to a study by Charles Gerba, we can be assured our shoes are hugging more than just our feet. The study out of the University of Arizona looked at 26 pairs of shoes and found that after three months of use, 93 percent of shoes have fecal contamination. The samples averaged 421,000 bacterial units per square centimetre — enough bacteria to reproduce and grow a new colony. Of those 26 pairs of shoes, seven had also managed to pick up E.coli.
This basically means that if you wear shoes inside, there’s poo on your kitchen floor. Even if you always leave your shoes at the front door, ask yourself where you put your handbag when using a public restroom.
What’s more, Gerba found that seven out of ten coffee tables of single men had fecal contamination. One would think (and hope) it’s from fellas resting their feet up on the table.
The Take-Home Message
According to the CDC’s National Center for Infectious Diseases, it’s estimated that in America 300,000 people are hospitalized and 5,000 die from a foodborne illness annually. Most deaths however, occur among susceptible populations that include small children, the elderly and people with weakened immune systems.
One thing you can be sure of is that from the moment your food makes contact with the floor, there’s some bacteria transfer occurring immediately. The extent of which depends greatly on the moisture level of food that was dropped, the size of the food, what type of surface the food came in contact with and of course what bacteria was already on the surface.
Whether you believe it’s salmonella, E. coli or the dreaded ’fecal content’ is your call.
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