3 Tips from a Microbiologist That Will Change the Way You Think About “Clean”

When it comes to cleanliness, appearance may not be as important as you think. Just because your kitchen counter looks dirty doesn’t mean it’s actually unhygienic—and a surface that appears “clean” (your toilet is the perfect example!) isn’t necessarily free from bacteria, unless it has been hygienically cleaned.

According to one microbiologist, true cleanliness has far less to do with actual dirt and more to do with the infection risk that comes with certain microbes (the scientific term for viruses, fungi, and bacteria). And, contrary to popular belief, not all microbes are actually bad.

“The word ‘germs’ can be misleading because we use it to describe any type of microbe, both harmful and non-harmful,” says Sally Bloomfield, Honorary Professor at the London School of Hygiene and Tropical Medicine and hygiene consultant with the International Scientific Forum on Home Hygiene. “The media often scares us by telling us there are ‘millions of germs on a dirty floor,’ when most or all of these aren’t harmful.”

In reality, Bloomfield says, harmful germs are more associated with things we do, like handling food, using the toilet, coughing and sneezing, and touching surfaces others have touched. So instead of judging an area’s cleanliness based on how it looks or feels, consider what happens there.

“One of the key things we are trying to do is dissuade the public from thinking that the most risky places in our homes are the places that are the most ‘dirty’ because they’re where the ‘germs’ lurk,” says Bloomfield. “The main sources of infection in our homes and workplaces aren’t actually dirt, but the people we live and work with, the food we buy, and our domestic animals. The riskiest times are when we are doing things that can allow infections to spread from these sources.”

For example, your kitchen counter might be sticky or crumb-ridden, but if it hasn’t been exposed to raw meat, there probably aren’t tons of harmful germs hiding out there. On the other hand, if someone with a cold has handled your door knobs or light switches, it’s probably time for some sanitizing.

To prevent the spread of microbes that could make you sick, Bloomfield recommends an approach called “target hygiene,” which is basically breaking the chain of infection by regularly cleaning the high-risk areas in your home with antibacterial products and, when necessary, bleach. With this approach, your sticky counters and actual dirt messes can wait—areas in your home with a higher infection risk are always the first priority.

“In the times that matter, the most critical sites to clean are usually the hands, hand-contact surfaces (like doorknobs and light switches), food contact surfaces (like flatware and cutting boards), and cleaning cloths,” she says.