Myth buster: Tick tock five

A survey conducted by the University of Illinois at Urbana-Champaign in 2003 found that 70 per cent of women and 56 per cent of men had knowledge of the five second rule. For those of you who do not know what it is — it is the idea that food picked off the floor within five seconds of its falling is safe to eat. It is sometimes said to have been given origin by Genghis Khan, who is held to have called it the 20 or so hour rule. Of course this is mainly speculation and there is no proof. 

Julia Child, a famous American chef whose popularity has been revitalised by a recent movie adaptation of her memoirs Julie and Julia might also have been responsible in all her cheerful clumsiness. Eating food off the floor, believe it or not, did not become taboo until the 19th century with the formulation of the modern germ theory. 

This rule is very pliable with the time being adjusted to how long it took to realise that food was no longer on our plates or in our hands and then the time involved in picking it up and popping it back into our mouths. The more we prize the treat that we had a few seconds ago, the more likely we are to retrieve it while no one is looking. We would want to bend the rules if it is the last candy in the bag more than we would for the first. The ‘forbidden fruit’ that it is lying there right in front of us after we may have perhaps sweated while in a queue and spent our entire pocket money on treating ourselves too, serves to amplify our cravings. 

In 2003 a high school student, Jillian Clarke initiated the rule to the test exposing gummy bears and cookies to contaminated surfaces. With assistance from the University of Illinois she discovered, quite surprisingly, that public floors did not contain that many disease causing germs. Another study conducted in 2006 by Dr Paul Dawson which appeared in the Journal of Applied Microbiology, revealed that certain organisms can survive for a long time on the floor. Using bologna sandwiches he found that 99 per cent germs are transferred to food within five seconds of exposure time from tiles, this was followed by wood and finally carpet. The bologna dropped on carpet contracted only 0.5 per cent of the microscopic bugs on the surface, the greater concern in this context being carpet fuzz. 

The factors which determine the number of microbes that hold fast to the dropped food include the type and texture of food. Ice cream is likely to get more contaminated than candy. The cleanliness and type of surface are also vital. And the longer food remains on the floor, more will be the number of bacteria who come to party like it is an open bar. 

Though scientifically the demise of the five second rule might have happened only a few years ago, I think our belief in it has been more of ‘naïve optimism’ and a kind of denial all along.