They are an eco-friendly solution to Earth’s plastic pollution crisis.
That is, if you can stand the grim army of bacteria lurking inside your reusable water bottle.
Stomach-churning studies have suggested that the bottles, adored by gym-goers and Love Island stars alike, can harbor 40,000 times more bacteria than the average toilet seat.
For this reason, some experts have described them as a ‘portable petri dish’.
The US-based researchers behind waterfilterguru.com conducted one of the bleakest studies on the bugs that persist in our water bottles yet. The study examined how colony-forming units (CFUs) were inside four popular types of water bottles. This is a unit commonly used to estimate the concentration of bacteria in a test sample. On average, they contained 20.8 million CFUs of Gram-negative bacteria.
The researchers also found two types of bacteria present in the reusable water bottles: bacilli and gram-negative bacilli. Gram-negative bacteria, including E. Coli and Klebsiella, can cause a number of serious infections, including pneumonia. While certain types of bacilli can also cause gastrointestinal problems, such as nausea, vomiting, and diarrhea.
To prevent bacteria buildup, experts recommend washing the bottle daily “with hot, soapy water.”
US-based Waterfilterguru.com, a team of water treatment experts and a member of the Water Quality Association, conducted one of the bleakest studies on the bugs that persist in our water bottles until the moment.
They found two types of bacteria present: bacilli and gram-negative bacilli.
Gram-negative bacteria, including E. Coli and Klebsiella, can trigger a number of serious infections, including pneumonia.
While certain types of bacilli can also cause gastrointestinal problems, such as nausea, vomiting and diarrhea.
The study examined how colony-forming units (CFUs) were inside four popular types of water bottles.
This is a unit commonly used to estimate the concentration of bacteria in a test sample.
On average, they contained 20.8 million CFUs of gram-negative bacteria.
The bottle with the spout and screw cap seemed to hold the most, at 30 million CFUs.
For comparison, a toilet seat has 515.
With an average CFU count of 20.8 million, reusable bottles can harbor up to five times the amount of bacteria found in a computer mouse (5 million) the researchers found.
It’s also a staggering 14 times the recorded amount of a pet bowl, averaging 1.48 million CFUs.
Other studies have suggested similar values.
Researchers at the US-based indoor air quality laboratory, EmLab P&K, recently found more than 300,000 CFUs per square centimeter in each of 12 bottles of water they tested.
However, despite the warnings, experts told MailOnline there was little evidence that the types of bacteria found in these water bottles are harmful to humans.
Dr Andrew Edwards, a molecular microbiologist at Imperial College London, said: “The human mouth is home to a large number and variety of different bacteria.
“So it’s not surprising that drinking vessels are covered in microbes.”
However, he also warned that household objects, including water taps, are already plagued by harmless bacteria.
Dr Edwards added: “While it is important to keep bottles clean, using hot soapy water, the mere presence of bacteria is not necessarily a problem.”
And there is no evidence from this study that the types of bacteria found are harmful to humans.
“In fact, domestic water taps are often colonized by many bacteria that have no harmful effect on humans.”
Meanwhile, Dr Simon Clarke, a microbiologist at the University of Reading, told MailOnline: “It really depends on which bacterium it is whether it’s a problem or not.”
“Having a high number of bacteria can be a sign that something hasn’t been cleaned in a long time, but it’s not necessarily dangerous.
“I’ve never heard of someone getting sick from a bottle of water, similarly, taps are clearly not a problem, when did you last hear of someone getting sick from pouring a glass of water out of a tap?”
He added: “The water bottles are likely to be contaminated with the bacteria already in people’s mouths.”
