The There Second Rule goes something like this: if you retrieve food dropped on the floor within three or five seconds, it won’t yet be contaminated.

Wishful thinking. Or an excuse not to throw otherwise good food away.

Let’s look at the facts. Disease-causing bacteria (known as pathogenic bacteria) and other microorganisms (such as viruses) are potentially everywhere and can be remarkably virulent. So logically, it would be an easy task for a microorganism to attach itself to a surface, especially to a moist piece of food.

A 2007 study from a team at Clemson University, tested the five-second rule on tile, wood and carpet. They contaminated the three surfaces with a high level of Salmonella Typhimurium and looked at the rate in which the bacteria transferred to bread and sausages, over a period of 24 hours.

Only to find, the amount of time food spends on the floor makes little difference to the transfer of bacteria. 

They found the most significant variable in the transfer rates from all three surfaces was not the length of time it had contact with the food. The three testing times (five, 30 or 60 seconds) made little difference in the rate of bacterial transfer.

The length of time the bacteria had been on the surface prior to contact with the food mattered more. Four hours after contamination, the same amount of bacteria remained on the carpet, while rates of bacteria on the tile and wood were slightly lower.

But another study, on bacteria in the manufacturing environment, found that the longer the food was exposed to a contaminated surface, the more bacteria it accumulated. As did an investigation on transfer between meat surfaces.

Overall, a comprehensive review on bacterial attachment to surfaces concluded that moisture, pressure and contact time increased the likelihood of bacterial transfer.

Next time you drop something on your carpets here in Roseville and contemplating the Three Second Rule, think about the findings of Microbiologist Kris Griffon.

Be sure to ask your Professional Carpet Care Specialist for “Carpet Shield” carpet and fabric protector.