What Does Science Say About the Three Second Rule?

You really were looking forward to taking a bite of that hamburger, carrot, Popsicle, gummy bear, you name it, but one second ago it landed on the floor. Within another second, you've swooped it up and are now considering the three second rule. Should this age old meme justify your blowing it off and sticking it your mouth acting like nothing happened?

Given that the three second rule is so well known, health experts weighing in on it is nothing new, but for those of you who may not have thought twice about eating morsels that have hit the floor, here's a little bit of scientific food for thought. The Daily Mail reports that researchers at Manchester Metropolitan University tested different foods -- bread with jam, cooked pasta, ham, a plain biscuit and dried fruit -- for different lengths of time on the floor. After three, five and 10 seconds on the floor, the researchers studied the food for any potentially harmful bacteria it may have picked up.

The Daily Mail has more on the results:

The study revealed that dropped foods with a high salt or sugar content were safer to eat after being retrieved, as is less chance of harmful bacteria surviving on such items.

Eating processed food from the floor poses the lowest risk -- one of its few benefits -- given that it generally contains such high levels of sugar and salt.

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MMU technical officer Kathy Lees said: "No specific organisms were detected on the biscuit, which has a low water activity level and low adhesion ability.

"Ham is a processed meat preserved with salt and nitrates which prevents the growth of most bacteria.

"The cooked pasta had a slightly increased yeast count after five seconds and very low levels of Klebsiella  were detected at all contact times, three, five and ten seconds."

The dried fruit also displayed Klebsiella after five and ten seconds and the yeast count was too numerous to count.

"The bread and jam showed no bacterial growth after time on the floor, which can be linked to the high sugar content of the jam which makes it unlikely to support microbial growth."

The Australian Broadcasting Corporation also recently reported on the three second rule, and their expert said it is really never acceptable to follow this practice:

Food technologies research scientist Phillip Button says it's never safe to eat anything that's touched the floor.

"From my understanding just don't bother".

"Even five seconds is enough for a substantial amount of bugs to latch on to the food."

Of all the germs that are on the ground or on the floor of your home, fecal matter is one of the most common contaminants says Dr Button.

Surprised? If you are strong proponent of eating food dropped on the floor for a short amount of time, researchers recommend frequent washing of the floor -- once a day -- with a mop-head that is replaced every three months or more. Button said while it may seem like carpeting would be a safer bet to eat from, hardwood and tile are most likely cleaner.

Featured image via Shutterstock.