 The controversial “five-second rule” — the one that lets us eat dropped food if it’s quickly scooped off the floor — is a bunch of boloney, according to Clemson University food scientist Paul Dawson, who stirred up the long-debated issue in this month’s National Geographic. Though previous research has shown we may have up to a minute to rescue certain types of spilled food before it becomes contaminated, Dawson and his students made a strong case for the “zero-second rule.” They found that salmonella and other bacteria can live up to four weeks on dry surfaces and be immediately transferred to food. (Chicago Tribune illustration by Michael Miner) 
 
 The zero-tolerance standard, however, conflicts with the findings of two Connecticut College student researchers who sprinkled apple slices and Skittles candies in the college dining hall and snack bar for five, 10, 30 and 60-second intervals. The apple slices did pick up bacteria after one minute, however and the Skittles showed a bacterial presence after remaining on the floor for 5 minutes.
– The 5-second rule may or may not protect your stomach from nasty germs (here's a no, here's a yes), but it probably depends more on location than duration, writes Julie Deardorff, who rounds up recent studies and talks to scientists for her Health Club column in the Chicago Tribune. Kitchen and bathroom floors, for instance, are nasty places where a 0-second rule is wise. The sidewalk, on the other hand, is safer because it's less likely to harbor the germs that cause illness. A kitchen floor "is probably a zero-second zone because the bacteria from uncooked meat and chicken juices are more hazardous than the ‘soil’ bacteria outside,” says one medical expert on the subject. Ditto for a bathroom floor because "it’s a great potential source of bacteria and shorter-lived viruses that can cause gastrointestinal illness if ingested.”