She is everywhere. At the gym, at the office, in the little ones' school bags. The water bottle is our new BFF. More than one in two French people use one daily, according to a study carried out in May 2022 by OpinionWay for Gobi. If this new everyday object is good for the environment (provided you don't collect it), is it also good for your health?
Unlike our plates, forks and cups which we wash after each use (normally), our water bottles rarely receive such attention. Are we right to wash them once a week, or even monthly? Are we really disgusting? And above all, can drinking water from a bottle make us sick? We asked microbiologists the question.
A “low, but not zero” risk
The risk of contamination by bacteria is “low but not zero”, according to Bruno Périchon, microbiology researcher at the Pasteur Institute. “In our mouth, we have millions and millions of bacteria. When you drink directly from the neck, they will settle inside the bottle and, if you don't clean it, grow. » Germs on our hands can also contaminate water.
“Bacteria coming from the skin, particularly streptococci, can cause diarrhea,” continues the microbiologist. If those present in the mouth develop in too large quantities, or if other more pathogenic ones appear, they can cause heart infections. »
Don't panic. “We are much more likely to get sick if someone coughs next to us,” says Marc-André Selosse, microbiologist and professor at the National Museum of Natural History. However, the probability is higher in young children, the elderly or immunocompromised people because they defend poorly against bacterial and viral infections.
Condition and contents of the bottle
It all also depends on the contents of the bottle. While water is unlikely to make us sick, the same is not true of sugary drinks. “There, you can develop bacterial biofilms which colonize the wall by feeding on the sweet juice,” specifies the microbiologist from the National Museum of Natural History. “These bacteria can survive for a very long time, and this is even more the case with plastic bottles,” adds Bruno Périchon.
Also pay attention to the condition of the bottle. If you carry it around and drop it regularly, remember to check its appearance. “A bottle with farts and corroded metal will allow bacteria to proliferate,” explains Professor Selosse.
Weekly washing
As you will have understood, the risks are therefore minimal, but biologists still advise washing your bottle regularly. “Once a week”, according to the researcher from the Pasteur Institute. With a bottle brush (which must also be washed), hot water and soap, vinegar or baking soda.
Of course, paying particular attention to the corners, edges, stopper and silicone seal. If the latter is black, it is because mold has invaded it and it is high time to change it. If in doubt, also throw away any water that has not been drunk during the day.
Microbes necessary for our health
Finally, the choice of water bottle matters. It is better to avoid plastic ones. “Not only do they release microplastics, but the bacteria will remain more on its walls than on those made of stainless steel or glass,” emphasizes Bruno Périchon.
No need to worry about the next sip though. Bacteria are not necessarily bad, insists Marc-André Selosse. “We are aiming for a sterile world but if certain microbes are dangerous, others are essential to our health. We are in a society that is so hygienic that it creates illnesses, such as asthma or allergies. » So we only have one thing left to say to you: health!
