Like most preemie parents, I am germ obsessed. In addition, working in a hospital is like living in a microbe spa, so I use alcohol based sanitizer liberally and I feel like I am always nagging the kids to use it as well.
But I am hearing more about “natural” sanitizers. Especially made with thyme oil. The makers of one “thyme based technology” brand, CleanWell, claim it kills 99.9% of germs.
I did a little research and checked with a friend, Jason Tetro, a crack microbiologist who blogs under the name Germ Guy. He is a hand hygiene guru (and born in Manitoba, which only adds another layer of awesome).
He says thyme oil extracts work pretty well against many bacteria and some viruses in the lab setting. With a virus, thyme oil damages the envelope, which is a protective coat around the membrane (the membrane is like the skin of a microorganism). The envelope is crucial to the ability of the virus to do its’ dirty work. So, if the envelope is damaged, the virus is basically inactivated. This is a really important point, because not all viruses have an envelope. Thyme oil is inactive against the actual membrane of a virus, so no envelope, no ability of thyme oil to work. That means thyme oil sanitizer will have no effect against the cold virus or the polio virus, as these viruses do not have envelopes.
Even though thyme oil has been tested against bacteria in a lab, it has never been tested on human skin (or if it has been tested, the results are not published anywhere that I could find). Another important point, because products interact with our skin (the oils etc.) and this could potentially alter how well they work.
Alcohol sanitizers kill all bugs by damaging proteins, the building blocks of the actual cell (remember, bacteria and viruses are a single cell). The concentration of alcohol must be at least 62% to have this instant kill effect. Alcohol hand sanitizers are even effective against the non-enveloped viruses, so unlike thyme oil, alcohol will kill the virus that causes the common cold. In addition, alcohol sanitizers have been tested on human skin, so we know they work in real life, not just the lab.
So we thought we would study a thyme oil sanitizer, CleanWell, head to head against an alcohol sanitizer, Purell. A nice little project for the elementary school science fair. We built an incubator box (meaning I built it), and each boy pressed their hand against some LB agar (a petri dish with nutrition to help the bacteria grow). One kid cleaned with Purell and the other with CleanWell (I supervised and timed for accuracy), and then we put the clean hands on a new set of petri dishes. Two days later we had our results (and by the way, like good scientists, we repeated the experiment to make sure we were right).
The alcohol was better.
The big blotches are bacilli (contaminants that probably come from the air and grew as expected on both plates). The alcohol plate has 3 distinct colonies of bacteria (large dots, and what we are most interested in looking for) that all looked the same (so probably same kind).
The thyme oil plate grew a lot more bacteria (many more dots) and at least 3 different kinds (you can tell by the sizes of the colonies and the color, note two are a yellow).
- Alcohol (ethyl alcohol) and thyme oil sanitizers are both made with natural products.
- Alcohol 65% tested under optimal conditions for a 7-year old, killed more bacteria overall and more types of bacteria than a thyme oil product.
- Because of how thyme oil works, it is not possible for it to kill the cold virus.
The alcohol sanitizer wins hands down! (Sorry, I couldn’t resist). And if you want to see a photo that shows the full awesomeness of alcohol sanitizers, check out this photo from the New England Journal of Medicine.
You want clean hands? You want an alcohol based sanitizer.