It is something that we’ve all said and used at least once in our lives: the five second rule. The official definition, as stated by Wikipedia, claims that “food dropped on the ground will not be significantly contaminated with bacteria if it is picked up within 5 seconds of being dropped.”
http://en.wikipedia.org/wiki/File:Five_second.png
Are there any truth in the famous 5 second rule? Or is it simply an excuse to eat food off the floor? It is definitely a question that sparks interest in many, including a student scientist by the name of Jillian Clarke.
The studies revealed that 50% of men and 70% of women use the rule regularly. It also confirmed that in fact 5 seconds is more than enough time for bacterial transportation. The research found that 5 seconds of contact with the floor was sufficient for an average of 150 to 8000 bacterial transportations. This staggering finding coupled with the fact that some bacterial infections only need 10 bacterial units to infect the human body makes one wonder if it is safe to eat foods dropped on the floor.
So just how fast do you have to pick up your food to inhibit micro-scale bacterial transportation? Jillian Clarke states that the world might as well call the rule a 1 femtosecond rule.
1 Femtosecond = 10^-15 of a second
http://www.hyscience.com/5seconds1.jpg
It is widespread knowledge that bacteria are everywhere. After all, there are more bacteria on your body right now than people living in America. I invite you to take out your cellular phones and touch your fingers to the “V” key pad. Congratulations, you’ve just touched an average of 6281 bacteria.
Knowing that there are harmful bacteria everywhere, humanity’s tolerance of the 5 second rule is a true testament of the profound immune system humans carry. It is a evolutionary feat of constant exposure to bacteria and other microscopic harm. In a world where allergies are dominant because humans live lives that are too clean, perhaps we should thank the 5 second rule as it may have done humanity more good than bad by evolving our immune systems.
