If you don’t know already, I am pretty diligent about washing my hands. It’s a great way to keep me, and others around me, from getting sick or putting the safety of the food I prepare at risk. (According to the CDC, “A large percentage of foodborne disease outbreaks are spread by contaminated hands. Appropriate hand washing practices can reduce the risk of foodborne illness and other infections.”)

Of course, there are those moments when I’m not around soap and water. Whether I’m at an outside food festival, blowing my nose in the car, or walking my dog at a dog park, there are just moments when soap and water aren’t readily available. In those instances, I make sure to carry some hand sanitizer.

Hand sanitizers are great when soap and water aren’t present, like when you’re outside or in the car. But it’s important to know that they can’t replace soap and water either. While they can reduce the number of microbes on the hands, according to the CDC, they do not eliminate all types of germs, including the parasite Cryptosporidium and the bacteria C. Difficle. Also, the type of hand sanitizer matters. Those with 60 to 95 percent alcohol are more effective at killing germs than those with a lower alcohol concentration or non-alcohol-based hand sanitizers. And if your hands are soiled, or you have been working with harmful chemicals or changing diapers, it’s more effective to wash your hands with soap and water because hand sanitizers aren’t enough to remove harmful germs and bacteria.

It’s also important to note that hand sanitizers cannot kill the norovirus, a foodborne illness that accounts for 19 million to 21 million illnesses a year. The norovirus is spread by eating or drinking contaminated foods and beverages, as well as sharing food or eating from utensils with someone who has the norovirus. For this reason, it is best to always try to wash hands properly—with warm soap and water, rubbing hands together for at least 20 seconds, before eating.

Washing your hands with soap and water is a great way to reduce the spread of germs and the chance of getting sick, but hand sanitizers can add an extra layer of protection in a pinch.