There’s nothing quite as refreshing on a hot, summer day as a cool glass of water. Many people often toss in some ice and lemon to add a boost of coolness and flavor to their drink. Between adding zest to contributing to detox drinks, lemon has become widely popularized as a drink add-in. However, there are some surprising (and germy) consequences of adding both lemon and ice into your water. These are the ways that this duo of ingredients can wreak havoc on your health.

Bacteria and microbes cling to lemons

Often times, a glass of water at a restaurant is accompanied by a slice of lemon attached to the lip of your cup. While you may not have given this extra wedge any thought in the past, the small piece of fruit could result in major health consequences. Back in 2007, a study published in the Journal of Environmental Health dug into the truth about the health and cleanliness of lemon wedges at restaurants. After testing 76 lemons from 21 different restaurants, the findings were clear: 70% of the lemon slices were contaminated. They contained a variety of viruses, bacteria, and microbial growth. The worst of these was E. coli., a dangerous microbe which causes numerous diseases in humans and animals. Additionally, an ABC study revealed that five out of ten lemons also include human waste on their surface.

How do restaurant lemons end up so dirty? The microbial growth, bacteria, and waste found on them can likely be contributed to behaviors in the kitchen. For starters, the ABC study showed that waiters and cooking staff often handle lemon wedges without gloves, tongs, or any other form of hand coverage. Whether the staff touches raw meat or doesn’t wash their hands thoroughly after leaving the restroom, tons of bacteria is transferred onto lemon wedges when they are picked up from the kitchen. Additionally, restaurant lemons often interact with surfaces that are already contaminated by unclean cutting board remains and raw meat, poultry, and fish, amongst other things. By the time a lemon wedge leaves the kitchen, it can be carrying a massive amount of gnarly bacteria and microbes with it.

The shocking contamination rates of ice

Unfortunately, as refreshing as ice is during the summer season, the ice from restaurants is often far from clean. In fact, it can often be even more contaminated than lemon wedges. In a 2017 study published by the Journal of Food Science, researchers found that there was a 100% transfer rate of E. coli onto ice when hands were contaminated with the microbe. When an ice scoop is introduced to the equation, the rate of transfer surprisingly shows a significant increase. While 67% of bacteria is left on ice when touched by human hands, a whopping 83% is transferred when using an ice scoop. These frightening numbers might make you think twice before you order a drink with ice in it at a restaurant. However, don’t panic too much drinking ice water probably won’t send you to the hospital.

Avoiding illness from this delicious duo

Fortunately, drinking a glass of water with lemon and ice in it, even if it is contaminated, likely won’t get you sick. Our immune systems are prepared to fend off bacteria and microbes like E. coli. It’s not likely that you’ll get ill from sipping down the refreshing, citrusy drink. However, there are ways that you can lower your risk of catching any illnesses from lemon water, especially if you plan to prepare the drink in your own home. If you take proper care of your lemons before serving them in any drink, lemon water can have tremendous health benefits.

It’s important not to keep your lemons outside of a cool environment for too long. In the Journal of Food Science‘s 2017 study, they discovered that lemons at room temperature experience a leap in rates of E. coli bacteria across the course of four to twenty-four hours. If lemon is contaminated by E. coli, the bacteria population can increase over five times during this window. Remember to wash your hands before serving lemons and to cut them on a clean cutting board to avoid contamination from your own germs or other food. It’s also best to avoid dumping a whole slice of lemon into your glass of water. Instead, squeeze the juice directly out of the lemon and toss aside the rind. You may be saving yourself from exposure to the bacteria that clings to the outside of a lemon.