Adam’s Journal
My wife recently picked up one of my all-time favorite brownies for me, but on the way home, she dropped it on the sidewalk. She couldn’t bear to throw it out, so she scooped it up and left the eat-or-toss decision to me.
So, what say you? (He asks, wiping tiny, brown crumbs from the corners of his mouth…)
Dr. Scofield Prescribes
Um, it seems I’m a little late to provide actionable advice. Still, had you consulted me in real time, I probably would’ve counseled you to step away from the chocolate-y treat.
We’ve all heard of the “five-second rule,” which – according to some unidentified quasi-medical authority – claims it’s safe to eat anything that falls on the ground so long as you rescue it within five ticks of the plummet. However, a 2016 study out of Rutgers University debunked that well-traveled piece of folk wisdom.
As soon as something hits the ground, it begins soaking up bacteria. Yes, the longer it stays in contact with the ground, the more germs it picks up. But there is no magic get-off-the-ground-germ-free period.
How much bacteria make the trip from ground to food also depends on two other factors: the food in question and the surface it landed on. The researchers found that the wetter the food, the more bacteria it soaked up. Hard, uniform surfaces proved most adept at facilitating bacterial transfer.
When it comes to outdoor surfaces like streets and sidewalks, it’s also well documented that bacterial levels are highest following a rainfall. But I’m guessing you wouldn’t have scooped up the brownie unless the ground was dry.
Nonetheless, even when dry, a hard, largely uniform surface like a sidewalk should be a fairly effective surface for transferring tiny critters to a somewhat moist confection like a brownie.
Warning: Here comes the yucky part.
A 2023 study of sidewalks in New York City found that fecal bacteria was ubiquitous. The bacteria, which can be antibiotic resistant, largely come from the poop of dogs, but also from other creatures like pigeons and rodents. Then all it takes is a bunch of human feet to spread it pretty much everywhere.
Now, Oklahoma City is not Manhattan. But like Gotham, we’re home to plenty of dogs and other defecating creatures. And even in our somewhat less populous city, they’re called sidewalks for a reason.
In other words, if I had to place a wager, I’d bet your delicious brownie came with a microscopic side of fecal bacteria.
Fortunately, the human immune system is pretty robust. By this writing, chances are that it will have taken care of any nasty bacteria you chowed down on alongside your treat.
–
Dr. Hal Scofield is a physician-scientist at the Oklahoma Medical Research Foundation, and he also serves as Associate Chief of Staff for Research at the Oklahoma City VA Medical Center. Adam Cohen is OMRF’s senior vice president and general counsel. Send your health questions to contact@omrf.org.
