Whoever came up with five-second rule had probably just dropped an entire cookie on the ground and needed a sanitary excuse to save it. However, according to research from Clemson University, such a cookie could have picked up toxic salmonella bacteria during that brief time window, especially on a tiled or wooden surface.
“If more of us valued food and cheer and song above hoarded gold, it would be a merrier world.” – J.R.R. Tolkien
Having said that, different foods produce a smorgasbord of results. Comparing the bacteria colonies picked up by dry saltines and wet pastrami after the sodium-rich snacks hung out on a contaminated floor for a few seconds, moist sausage tends to pick up far more flora.
Even food that has spent a mere two seconds on a contaminated surface can be considered suspect. The “five-second rule” seems to be a juvenile fiction. In fact, even if something spends a mere millisecond on the floor, it attracts bacteria. How dirty it gets depends on the food’s moisture, surface geometry and floor condition – not time.
Sad news for clumsy eaters and students everywhere: the “five-second rule” is a myth.
“You could also ask who’s in charge. Lots of people think, well, we’re humans; we’re the most intelligent and accomplished species; we’re in charge. Bacteria may have a different outlook: more bacteria live and work in one linear centimeter of your lower colon than all the humans who have ever lived. That’s what’s going on in your digestive tract right now. Are we in charge, or are we simply hosts for bacteria? It all depends on your outlook.” – Neil deGrasse Tyson, Space Chronicles: Facing the Ultimate Frontier