BACTERIA IN YOUR HOME: even your microwave and smartphone have their microbiome!
Artemia (Latin: Artemia) is a genus of lower crustaceans. They live in salt lakes and feed on microscopic algae. They can survive and reproduce in extremely salty water and are considered extremophiles / facebook.com
For those who are extremely sensitive to the sanitary conditions of their home and workplace, this news might be shocking. A new study published in the scientific journal Nature revealed not just the presence of bacteria in all of our household gadgets…
We live in a society of microorganisms, and there is no way to change that. It would be strange if they weren’t present in our wardrobe, oven, or bed. However, scientists have discovered that they don’t just live there. Even inside household and laboratory electrical devices, they form stable ecosystems — their own unique, incomparable world.
THE FANTASTIC ABILITY TO SURVIVE
Extremophiles — this is what scientists call organisms that are capable of surviving and even thriving in the harshest conditions. These could be scalding hydrothermal vents, Antarctic ice with extremely low temperatures, or the crushing pressure of the Earth’s crust… Their extraordinary ability to adapt, which is beyond the reach of our species, is truly mind-blowing, though it has long ceased to be scientific news. However, no one suspected that extremophiles could inhabit the exact places where humans live — until they were discovered in an extreme yet familiar environment to us: household microwave ovens.
IS THERE LIFE ON A DEVICE?
Previous research has already found isolated microbial communities in kitchen appliances. If you think dishwashers and coffee machines are free from them, you are mistaken. Dishwashing chemicals, boiling water, and hot steam are no match for them.
Microbes not only survive but persistently exist in household appliances, forming communities that are adapted to their environment. However, for the first time, a unique microbiome was discovered inside microwaves.
Why was this surprising to scientists? The most cited journal in microbiology, Frontiers in Microbiology, states that this discovery challenged a widely held misconception.
MYTHS ABOUT BACTERIA AND MICROWAVES
There is a common myth that microwave radiation heats and ultimately kills bacteria, including those that cause foodborne infections like Escherichia coli and Salmonella. However, these well-known myths were once called into question.
Commenting on the study results, Canadian microbiologist Jason Tetro reminds us that this myth originated in the 1980s when the widespread belief emerged that the microwave «kills everything.»
It’s possible that appliance sellers used this clever marketing strategy, as microwaves have become a nearly essential feature in modern kitchens. However, this idea had a downside, as eco-activists claimed that if microwaves «kill everything,» they must also be harmful to human health.
THE «FATHER» OF THE MICROWAVE
Let’s recall that microwave ovens work by heating with electromagnetic radiation in the decimeter range. The radiation accelerates molecules within a substance, increasing intermolecular friction and, as a result, raising the temperature.
This ingenious device was invented by Percy Spencer back in the mid-1940s — and entirely by accident. He worked for a company involved in radar technology and one day discovered that the high-frequency radiation had melted a chocolate bar in his pocket. The first models patented by Spencer were gigantic, weighing 340 kg and standing 1.8 meters tall.
Along the way, Percy also invented popcorn: by applying microwaves to corn kernels, he noticed how they exploded from within. Interestingly, Spencer, who lost his parents at a young age, never finished high school. Yet that didn’t stop him from becoming the holder of 150 invention patents.
BACTERIAL ECOSYSTEMS — EVERYWHERE!
No matter how unusual the story of the microwave’s invention may be, we now know that potential pathogens can even be present in these «dangerous» appliances. Alba Iglesias, a microbiologist from the University of Valencia in Spain, and her colleagues studied swabs taken from 30 microwave ovens.
Some of these microwaves were located in homes, while others were used in larger spaces such as offices, cafes, and laboratories. They were used to heat samples and chemical solutions. The team then cultured the samples in Petri dishes — shallow, cylindrical transparent containers.
The scientists identified the genera of the grown microbes to understand their bacterial diversity by sequencing the DNA from the original biomaterial.
THE SAME AS ON HUMAN SKIN
In total, 101 bacterial strains were grown in laboratory conditions. The dominant strains were Bacillus, Micrococcus, and Staphylococcus, which typically live on human skin and on surfaces frequently touched by people.
These bacteria were present in all types of microwaves, but they were more abundant in household and shared-use appliances. Some cultures also revealed types of bacteria capable of causing various diseases, such as Klebsiella and Brevundimonas.
POTENTIALLY DANGEROUS NEIGHBORS
The WHO recently classified Klebsiella as one of the most dangerous bacteria due to its resistance to existing antibacterial drugs. In some cases, it can cause prostatitis, wound infections, and pneumonia. Brevundimonas is one of the few bacteria capable of surviving in Martian conditions.
When buried 30 cm deep in Martian dust, this bacterial population can withstand cosmic radiation for 100,000 years before beginning to diminish. So, a microwave, which has the shortest lifespan of all kitchen appliances — an average of about nine years — is child’s play for it.
Brevundimonas is often found even in purified drinking water, as it is resistant to nearly all bacterial filters. It can sometimes cause sepsis, endocarditis, urinary infections, pneumonia, meningitis, purulent arthritis, and more.
EXTREMOPHILES CAN BE USEFUL
But if you want to meet the most extraordinary extremophiles, you don’t need to travel to Mars or Antarctica. Laboratory microwaves, rather than household ones, contain the most unusual genetic diversity of bacteria.
Researchers discovered both «kitchen» bacteria and extremophiles in these devices. These strains are capable of withstanding radiation, high temperatures, and lack of moisture, and scientists believe they are the result of prolonged evolutionary selection in laboratory conditions.
They could have biotechnological applications, such as in bioremediation of toxic waste.
REGULAR CLEANING, NO PANIC!
In the future, experts plan to study more thoroughly how microwaves affect bacteria over long periods. But for now, the general public can take away a few crucial conclusions from their discoveries.
First, your microwave, like any other household appliance, is not the most «sterilized» place in your home. Second, it is also not a deadly pathogenic reservoir. Scientists say there is no need to fear household appliances. You simply need to regularly clean your kitchens and laboratories, ensuring surfaces are free from potentially harmful bacteria.
Original research:
