The Five-Second Rule or How Dirty Is That Salami?

The rule applies to foods that have fallen to the ground. Normally, customary rules of hygiene dictate that food that has fallen to the ground should be discarded, in order to prevent ingestion of disease-causing agents acquired from the dirty surface. The rule states that if the food is picked up within five seconds, it can still be eaten.
The true pioneer of five-second research was Jillian Clarke, a high-school intern at the University of Illinois in 2003. Ms. Clarke conducted a survey and found that slightly more than half of the men and 70 percent of the women knew of the five-second rule, and many said they followed it.
She did an experiment by contaminating ceramic tiles with E. coli, placing gummy bears and cookies on the tiles for the statutory five seconds, and then analyzing the foods. They had become contaminated with bacteria.
For performing this first test of the five-second rule, Ms. Clarke was recognized by the Annals of Improbable Research with the 2004 Ig Nobel Prize in public health.
It’s not surprising that food dropped onto bacteria would collect some bacteria. But how many? Does it collect more as the seconds tick by? Enough to make you sick?
Prof. Paul L. Dawson and his colleagues at Clemson have now put some numbers on floor-to-food contamination.
Their bacterium of choice was salmonella; the test surfaces were tile, wood flooring and nylon carpet; and the test foods were slices of bread and bologna. ( more from NYtimes )