This article is about a myth regarding fallen food. There is also an article on ice dancing which has a five second rule.

The five second rule is a popular North American old wives' tale used to justify eating food that has fallen to the ground. The use of this term is generally accredited to various fast food restaurants, which some allege to have endorsed such a policy when preparing food. Those who use the five second rule falsely claim that foods, particularly sweet foods, like cookies, that have fallen to the ground, will not contract any germs until five seconds have passed. If they are quickly retrieved from the floor, then the individual will usually mention the five second rule before eating the food in the presence of others. Although it is unlikely that any harm would come from eating food from a relatively clean floor, the notion that germs from the floor would not reach food for at least five seconds is false. The rule therefore seems to have been invented out of convenience, and to prevent others from criticizing the habit of eating fallen food.

The five second rule is seldom invoked in the case of wet and sticky foods, such as ice cream, since dirt often clings to the food, leading to obvious hygiene issues. A somewhat scientific experiment performed by Katriel Ramu and Jean Barker at the University of Maine demonstrated that dry foods were exposed to more bacteria than wet foods when they were on the floor for equal periods of time, contrary to what one would expect. From this, Ramu and Barker concluded that dry foods follow the five second rule, and wet foods do not. They also postulated that if children were permitted to use the five second rule, they would provide challenges to their immune system, which could be beneficial to their health.

Another study conducted at the University of Illinois found that the transfer of bacteria from floor surfaces to foods happens immediately, particularly with smooth foods falling on smooth surfaces and even more so with foods like meat, cheese, and vegetables. Those foods have higher levels of naturally occurring microflora , compared to cookies and candy. However, the floors that were swabbed were found to be mostly free of microbes. Jillian Clarke , a high school senior in 2003, researched the five-second rule during her seven-week internship at the University of Illinois. She found that seventy percent of women and fifty-six percent of men were familiar with the five-second rule, and most utilized the rule in their decisions to eat food that had fallen on the floor, though women were more likely than men to use the rule. Cookies and candy were more likely to be picked up than broccoli or cauliflower. Clarke's work won an Ig Nobel Prize for Public Health in 2004.

The five second rule is sometimes called the ten second rule or the fifteen second rule, to some extent depending on the quality of the food involved or the intoxication level of the individual quoting the rule. For example, in college dormitories the ten second rule is often quoted as the drunk version of the five second rule.

There is a related justification for eating just-fallen food, where the individual will "kiss it up to God", that is, the item is literally kissed just before being eaten. Generally, this only "works" if done in the same five to fifteen second time frame.

Other occasions which call on a "five second rule" include:

• Once a seat has been vacated for five seconds, the five second rule is said to be in effect and anybody may take that seat.
• If a teacher is more than five minutes late to a lesson, it is believed by some students that it is acceptable to leave. Note: This is generally not accepted by teachers, although some schools have offical policies that allow students to leave without penalty if an instructor is sufficiently tardy.
  • Add five minutes per degree if in college. That is, one waits fifteen minutes for a professor who has a Ph.D..

External links

• Article on the five-second rule experiment
• Article on another experiment conducted by Jillian Clarke and Meredith Agle
• Message board posting

References