Do you follow the five seconds rule? Well, I guess it really depends on what food you drop on the floor. If it's popcorn, obviously not; but if it's a HK$100 piece of chutoro (fatty tuna belly) sushi, you'd probably pick it up before you count to five and eat it.

Now, it turns out this old wives' tale is true, but it may still be dangerous to follow it, according to research published last month by Clemson University food scientist Paul Dawson and his team in South Carolina. The team contaminated surfaces, such as tiles, wooden floors and nylon carpets, with the toxic bacterium salmonella, then dropped slices of bread and bologna on them. They timed their exposure from a few seconds, minutes, hours to days. It turns out that, yes, the longer the exposure, the more bacteria contaminate the food.

The researchers said 10 salmonella bacteria and less than 100 from a deadly strain of E coli are enough to cause serious damage to your health. And just a few seconds of food exposure is enough to accumulate that many germs. So the moral? Don't drop your food.