Is there any scientific support for the "5-second rule"?

Yesterday at Mom’s house, an entire cheesecake took a nosedive when she tripped over the dog. Splat - half on tile, half on carpet. We all shared a dismayed look (no cheesecake?) before a chorus of “5-second rule!” as we lept to salvage what slices we could.

Which, of course, got me to a-wonderin’. Outside of a greed for cheesecake, is there any reason to think the 5-second rule makes sense? Are there bacteria on floor tile which would be dangerous to ingest, or are floors considered dirty for no good reason? What about carpet? Does more time exposure = more contamination possibility? (would it make just as much sense to have a “5-minute rule”?)

No, but there’s evidence against it. There was a study somewhere… there’ll be a cite later.

Here’s a snopes article on the subject. Sorry-- It seems the 5 second rule is just wishful thinking.

Jillian Clark, at Howard University, just won an Ig Noble prize for her work disproving the 5 second rule.

You would probably be amazed and disgusted at what you could grow on culture plates if you took a random sample of pretty much anything. I know I was. Fortunately, if you have an immune system and are not getting huge doses of bacteria, you should be OK.

Here is a brief news article from last fall about the awards that the amazing Captain Amazing mentions. It really depends on how damp the surface is. Wet surfaces are a good medium for bacteria. Dry surfaces are not. This has been intuitive to me (and many others I would guess). If your food goes plop into wet sludge on the floor, 0.05 seconds would be too long for me to want to salvage it. There is nothing magic about the five second time period.

If you kiss it up to God, it’s good to go.

Right, I think the more important question here is: what bacteria can you pick up off the floor that is going to be pathogenic that isn’t just as likely to be on the coutner top?

The real key is to sterilize it by blowing on it. That’s what’ll keep you from getting sick.

It never occurred to me that anyone took the 5-second rule literally.

I always just thought it was a semi-humorous way of saying:
–that the floor isn’t necessarily that dirty
–and even if it was, the chances of picking up something bad are slim
–and even if the food does get a “germ” on it, it’s unlikely to actually end up affecting you
–and I’m willing to take that chance because I really want some cheesecake.

Just to be clear, Green Bean, I’ve never taken it to mean any more than your 4 points. I was just wonderin’, ya know, if I could bolster my weak position with a few facts ‘n’ figures.

Heck, the floor’s cleaner than my mom’s kitchen sponge, according to the Terrifying Health Watch Report of DOOOOM [sup]TM[/sup], so I’m not too worried in real numbers. (Seriously, that report scarring housewives with the details of bacterial counts in damp sponges was the most brilliant marketing ploy by sponge manufcturers I’ve ever seen. My mother and aunts are flipping out about dirty sponges, but their use of them is so ingrained, they won’t switch to, say, washable towels. So what do they do? They now replace their sponges once a week and buy the more expensive, “anti-bacterial” sponges! Brilliant, I tell you!)

But I guess I did sort of wonder if more bacteria would stick to food the longer it remained in contact. Short of remaining there long enough to grow more bacteria, it seems the answer is no, bacteria stick more or less instantly.

I’ll still eat the cheesecake next time it happens, though. :stuck_out_tongue:

Oh, I didn’t think you yourself believed it WhyNot. I was surprised that enough people believed it that Snopes felt the need to debunk it. And I was also surprised at the seemingly negative reactions to Jillian Clark’s high school science project. (A very clever project idea, btw.)

I’m totally with you on the sponges. I’m just about the least germ-phobic person you’re likely to meet, but I get completly grossed out by people and their sponges.

You know, sponges don’t bother me at all. I think I keep the same sponge for months at a time. At least until it turns odd colors. I think I’ve gone through three or four kitchen sponges in the last year. At the most.

I’m surprised you guys managed to get to the cheesecake BEFORE the dog did!

I love the commercial that shows the woman wiping the countertop and fridge with the raw chicken! :slight_smile:

He got one slice, lucky little daschund! He was so shocked, like manna from heaven - he froze for a moment, as well. Recovered just a few microseconds before the rest of us and grabbed a nice cherry swirl slice!

Obviously, daschunds have a “4 1/2 second rule”.


In a house with one or more dogs, it probably should be written as a 5 millisecond rule, as far as bacterial contamination goes.
And it should be obvious that this was no accident. “Oh my, did I trip you Mom? Dear me, bad doggie. Cheescake…goooood.” :smiley:

You can steralise sponges by zapping them in the microwave for a few seconds until they come out steaming. That might save you a bit of money.

This got a good laugh from me because it is exactly what I do. “A bit of cat fur? I’ll blow if off.”

Yeah, the cat fur is a far bigger hazard than germs in my house at least. Where do we pick that up, anyway? Does each little kid separately invent the notion that we’ll blow all the germs off the food? Actually, I’m fairly sure my mother taught me that. Aren’t mothers supposed to try to convince little children to be cleaner, not dirtier?