We've all heard of the stomach-flattening properties of detox water, and many of us rely on a simple recipe daily—adding a slice or wedge of lemon to every glass. While this practice is super-common, and an easy and affordable way to pep up plain H2O, it turns out lemon lovers could be ingesting a lot more than they think.
Cafe lemon water is seriously, surprisingly gross. Like, maybe don't drink it gross. A 2019 study conducted by the journal Food Protection Trends found that salmonella survives very well on lemon wedges that aren't refrigerated and that salmonella from the fruit can get into your water. Kind of terrifying, right?
Well, it gets worse, because that's not the only study that's contained similar results. In a similar experiment conducted by Philip Tierno, Ph.D., Director of Microbiology & Immunology at New York University Langone Medical Center, researchers found that half of lemon wedges collected from various restaurants were contaminated with human fecal matter. Let's let that sink in for a minute, shall we? Fecal matter. It seems like those "all employees must wash their hands upon using the restroom" signs are actually necessary. Apparently Tierno believes that this could be due at least in part to a tendency for restaurant staff to either not wash lemons at all, or just give them a quick rinse. Among the specimens of microbes collected were E. coli, staphylococcus epidermidis and candida. Yep, the same candida you're thinking of.
Before you freak and call your doctor, Tierno says that though there is a risk of getting sick, it's actually quite small: "The usual course will probably result in no infection, but there is a possibility." This brings us to the flip side of this dilemma: there are plenty of things we do and touch each day that are covered in bacteria and could get us sick. The subway railings, our credit cards, anything bought from a store—these things are all potentially awash with bacteria. So is every inch of our skin. However, there's a difference between good and bad bacteria, and the bacteria detected on the lemons is decidedly bad.
There are a few things you can do to limit risk. The primary one is just to squeeze a lemon slice or wedge directly into your drink, instead of putting it in and letting it float there. Asking for water with no lemon is a common request at restaurants. You can just save your lemon-water cravings for home, where you know the lemons will always be freshly washed.
Survival of salmonella on lemon and lime slices and subsequent transfer to beverages. Food Prot Trends. 2019;39(2):154-161.