Almost 1 year ago, Tasha Sturm, a microbiology lab technician at Cabrillo College, posted the photo above. It is a bacterial culture of her 8-year-old son’s handprint. She had her son place his hand on a large petri-dish after he was playing outside, and this is what grew! Amazing!

This image has made the rounds on the internet over the last year. The reason I am writing about it today is that it has unfortunately (and almost unanimously) prompted the opposite of the correct response from the people who see it. This is entirely due to lack of information and understanding.

The average person’s reaction is some combination of the following: “Ewww! Gross! I need to wash my hands! I need to wash my kids’ hands! I need some more anti-bacterial soap! I’ll never let my kid outside!”

Now, let’s deal with reality. There are bacteria everywhere. EVERYWHERE! In the dirt. In the air. On our food. In our water. On our skin. In our body! In fact, we need bacteria to survive. Our intestines are filled with bacteria, and hopefully most of it is good bacteria. But you know what? Some of those bacteria on or in us, are bad bacteria… bacteria that could kill us. But do you know why it doesn’t? Because of the good bacteria. The good bacteria entirely outnumber our bad bacteria; they overwhelm them and out-compete them. They give our immune system a fighting chance to beat the bad bacteria. If we didn’t have the good bacteria, we would be dead.

Close-up of some of the bacteria colonies.

Close-up of some of the bacteria colonies.

Now, let’s take a closer look at the photo above. Do you know what kind of bacteria are present in this handprint? These likely include Bacillus species, Serratia species, Micrococcus species, Staphylococcus species, and yeast species. All of these microorganisms are normally found in the soil and/or in the water and/or on the skin.

Tasha Sturm stated in an interview, “We have a large number of bacteria that live ‘with us’ that are beneficial. Some aide in digestion, make vitamin K, etc. People who are healthy come in contact with millions of bacteria every day without adverse effect. Coming in contact with bacteria actually strengthens our immune system.”

She added, “Unless your kids have a health condition that requires you to be more vigilant let them have fun and get dirty; it’s what they need to develop a healthy immune system.”

So, how do we strike a balance between good hygiene and developing a healthy immune system? If you touch or may touch something that is known to contain unhealthy bacteria, then wash your hands. If you touch or may touch something that could spread disease or cause infections, then wash your hands. This includes washing your hands after using the bathroom, after touching a dead animal, and before eating. And teach your children to do the same. But seriously, let’s be wise in this and don’t go overboard. Touching an animal that has been dead for a week is different than touching a dead animal you butchered yourself (yes, this is a Permaculture/Homesteading website!).

Also, please use antibacterial soap very sparingly. We don’t want to kill all bacteria in our environment or on our bodies. As a physician, I need to use antibacterial soap on a regular basis in the Emergency Room, but at home, I just use regular soap. Again, I recommend balance.

Tasha Sturm concluded by saying, “As microbiologists, our job, especially in education, is to make the invisible world visible so it’s easier to understand. I think the image of the handprint was a graphic way to show others what’s out there and the beauty of microbiology. I think this image did just that.”

I agree!


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