The potential issue isn’t the lemon itself. The concern is handling and cross-contamination. Like other fresh produce served without additional cooking, lemon wedges can pick up microorganisms from hands, equipment, surfaces, or improper storage. Once sliced, the exposed flesh also provides another surface that can become contaminated.

Still, finding bacteria on restaurant lemons doesn’t mean that every lemon wedge is dangerous. Many microorganisms are harmless, and detecting bacteria doesn’t automatically mean enough disease-causing organisms are present to cause illness. Proper restaurant hygiene, clean utensils, handwashing, and appropriate storage substantially reduce food-safety risks.

If you’re concerned, the simplest option is to order your water without a lemon wedge or request lemon juice separately. People with weakened immune systems or others who need to be especially cautious about foodborne illness may prefer avoiding garnishes that have been handled extensively and are served raw.

For most healthy people, an occasional lemon wedge in restaurant water isn’t a reason to panic. The useful takeaway is simply that food safety depends heavily on proper handling. That innocent-looking slice of lemon has often traveled through several preparation steps before reaching your glass, making good hygiene far more important than the fruit itself.