Is It Gross to Drink Out of a Can Without Washing It First? We Asked an Expert.

My childhood was ripe with rumors and old wives’ tales. If you grew up in the ’90s, you may know the ones — like if you say “bloody Mary” in the mirror, a ghost will appear, or if you say “light as a feather, stiff as a board,” you can make your best friend levitate.

But the childhood rumor that sticks out to me the most isn’t scary — it’s just disgusting. Somewhere in the journey of adolescence, I learned and believed that soda cans have rat excrements on them from the factory and should therefore be thoroughly washed before contact with one’s mouth. Have you heard this one before?

Fast forward to 2020, and germs are on the forefront of just about everyone’s mind (this time, for a bona fide reason). But the can/germ issue feels especially important because I don’t think I’m the only one pounding sparkling water like it’s my job. So I’m obligated to circle back to my question from 1997: Is it gross to drink out of a can without washing it first?

To find out, I did a little digging. And, to be honest, I didn’t see much in the way of empirical research on whether soda cans have rodent pee on them. I did, however, come across a news story on CBS from 2013. A news team conducted an informal study on soda cans and bottles with a local lab, and they found that yes, these drinking vessels can be pretty gross. 

For example, one can of diet cola sourced from a chain restaurant had staphylococcus on it, the bacteria that causes staph infections. A soda from a vending machine outside of a supermarket was covered in pseudomonas aeruginosa, a type of bacteria that can lead to pneumonia or UTIs. And, probably the most disgusting, the dust on top of an energy drink from a gas station had coliform particles in it, which is — how do I say this lightly — poop.

To learn more about how concerning this really is, I spoke with Amesh Adalja, an infectious disease physician and senior scholar at the Johns Hopkins University Center for Health Security. He told me it’s likely someone didn’t wash their hands after using the bathroom, then touched the can and transferred the coliform. Or, confirming my childhood suspicion, an animal may have left droppings on the can, whether in the factory or the store itself.

It’s certainly alarming to learn your drink could have excrement on it, but Adalja assured me it’s not necessarily a reason for alarm. Theoretically, coliform could cause a GI illness in the drinker. “But in general, coliforms are an indicator of an organism; they don’t necessarily mean there’s bacteria that will cause an infection,” he says. 

Also, whether or not the coliform spreads harmful bacteria, viruses, or parasites to the drinker depends on how the can or bottle is being stored. For example, Adalja says, pathogens aren’t as likely to survive in the coliform residue if the can or bottle is stored in a cooler, which most drinks are these days.

The bottom line: Most importantly, Adalja emphasized we live in a germ-filled environment, and it’s normal to come in contact with gross things. If you want to play it extra safe, rinse off the can before sipping on it, or pour your drink in a glass. But rest assured that no matter where your can has been on its journey to your mouth, Adalja (and the results of that aforementioned article I was talking about) says that if you’re an otherwise healthy person, it’s not necessary to clean or sanitize it unless there’s visible dirt.