Why The 'Three Second Rule' Makes No Sense For Food

There's a widespread belief that food dropped on the floor won't risk contamination if you pick it up within three seconds (or, depending on who first told you, five seconds). As RMIT research officer Philip Button points out in an article at The Conversation, the reality is rather more complicated than that.

Picture by Onay Davus

Existing studies suggest that a wide variety of factors, including moisture, the pressure on food, the length of time bacteria has been on an existing surface and the length of time food has contact with the surface all influence the rate at which bacteria is transferred.

Button also notes that worries about food on the floor may be misplaced: because bacteria can also survive on other objects such as mobile phones, the risk of food getting contaminated by you is potentially just as high or higher as what the floor can inflict. Washing your hands before cooking and eating thus makes sense (and we've got a detailed guide on how to do it properly).

I tend to fall in the "let's not be overly precious about our exposure to dirt" camp, partly because it always seems to me that the people who obsessively use hand sanitiser are the ones who catch everything going around. In your own house, you'll know how clean the floors are, and whether that banana you've dropped will be fine after a quick rinse. "When it doubt, don't" is a good rule, but taken to extremes it's also a wasteful one.

Monday’s medical myth: the three second rule (when food falls on the floor) [The Conversation]


    No one actually believed these 'rules' did they? I've only ever heard it from the mouths of mothers, and I assumed it was short for "I couldn't be bothered peeling/getting/making another one, so, Junior, if you die because you threw this one on the ground, so be it". And fair enough too. Kids need to eat more dirt.


      I don't think anybody except 5 year olds ever seriously believed this, although in my case it was "brush it off, you'll be fine" rather than some arbitrary time limit.

      In any case, yes, kids need to eat moar dirt.

        both beat me. I was gonna say... people actually believe this?

        Do they also believe that saying something at the same time as another person legally necessitates saying 'jinx'? (it does).

    Didn't Myth busters do this one?


    I'm pretty sure saying "three second rule" has always just been an excuse to placate the overly sensitive.

    Surely nobody is stupid enough to believe these "rules". Surely.

      Sure they are! and stop calling me Shirley..! :)



    Hey, someone was silly enough to write an LH article on the subject... Surely there must be an article on how to cook a hamburger on the latest Android phone or something that would be more useful than this rubbish?

    I prefer the new iPad as my cook top, it gets hotter and has a larger heat radius

    I say it all the time, 3 seconds for some food, 5 seconds for others then 10 seconds if its really delicious, dry and the last one or expensive.

    But i never actually believed it (nor believed that there was any real difference between 3 and 10 seconds), i'm just not a germaphobe, sure if it dropped by where i was cutting up raw chicken id probably throw it out. The only reason I'm more inclined to throw out 'wet' food is because of other crud sticking to it.

    *Food hits floor*

    Little Germs: 'Let's get it!'

    King Germ: 'No, we must wait 5 seconds!'

    If you've ever seen a toddler eating handfuls of sand at the beach or playing with a family pet, you'll understand that we have pretty good resistance to most stuff on the ground. Also - personal sanitisers = bottled water.

      We were still in the 'sanitising bottles' stage with our boy, then realised he was kissing the dog and figured there was no longer any point...

Join the discussion!

Trending Stories Right Now