Whether it's lemon wedges floating in a jug of iced water, limes muddled into a mojito, or slices of orange sitting on top of your sangria, fruit in drinks signals summer relaxing.

But just how clean are those citrus slices?

In a study published in the Journal of Environmental Health, researchers studied samples of lemon slices that were in drinks at 21 different restaurants. They found almost 70 percent of the samples produced some sort of microbial growth, including 25 different microbial species.

"The microbes found on the lemon samples in our investigation all have the potential to cause infectious diseases at various body sites, although the likelihood was not determined in this study," the researchers wrote in the journal. "Restaurant patrons should be aware that lemon slices added to beverages may include potentially pathogenic microbes."


Clinical professor of microbiology and pathology at New York University School of Medicine, Philip Tierno, agrees with the findings, and said his own study found traces of E. coli, enterococcus, staph, and the norovirus on pieces of citrus fruit.

"People are touching the lemon in your glass, handling it, cutting it, placing it in a container or a cup, or a glass; and then picking up those slices at a later point in time and dropping them into a drink and putting them on the rim of a glass," Tierno told Elle. "You can easily see how those lemon slices and lemon wedges can be contaminated.

Although the fruit may be washed, it is ineffective if bartenders and restaurant staff fail to practise good hand washing.

And while you might subscribe to the theory that the alcohol in the drink should oblietrate any germs on the fruit, Tierno says that's not strictly true.

While alcohol can kill some bacteria, the drink would have to be virtually straight alcohol for that to happen, he said. And even if you were knocking back some stiff drinks, straight alcohol can only kill bacteria, and not viruses.

One expert recommends asking for lemon wedges on the side and squeezing the juice into the drink. Photo / 123rf
One expert recommends asking for lemon wedges on the side and squeezing the juice into the drink. Photo / 123rf

Despite his research, Tierno says he still allows the odd piece of lemon in his drink if he's out at a bar, but his advice is to pay attention to how the drink is made. He returns the drink if he sees the bartender use a dirty rag to clean a glass, or if they put their fingers on the rim of the glass.

He says if you are especially worried about germs, ask for the lemon wedges on the side and squeeze the juice into your drink, rather than dunking in the entire wedge.