Reusable water bottles hold more bacteria than toilet seat, study finds

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A new study has delivered a disturbing finding about everyone’s favourite comfort crutch, the humble drink bottle.

The chokehold so-called “emotional support water bottles” have on society cannot be understated: the trend emerged during lockdown, and has since garnered hundreds of millions of views on TikTok.

“They are objects that can’t betray us,” Australian Catholic University clinical psychologist and hoarding disorder expert, Associate Professor Keong Yap, told The Sydney Morning Herald, comparing the phenomenon with objects children use to soothe anxiety (like stuffed toys). “They are reliable and predictable, unlike people who can hurt us.”

Turns out they can, however, “betray” you – if you don’t clean them regularly.

A recent study from US-based waterfilterguru.com found reusable bottles can harbor 40,000 times more bacteria than the average toilet seat – describing them as being like a “portable Petri dish.”

Researchers swabbed parts of different water bottle three times each – including the spout lid, straw lid and squeeze-top lid – and found two types of bacteria present: Gram-negative rods and bacillus.

Gram-negative bacteria can cause infections that are increasingly resistant to antibiotics – while certain types of bacillus can result in gastrointestinal issues.

Comparing the cleanliness of the bottles to household objects also painted a dirty picture: they contain twice as germs as the kitchen sink; can harbor four times the amount of bacteria as a computer mouse; and 14 times more than a pet’s drinking bowl.

“The human mouth is home to a large number and range of different bacteria,” Imperial College London molecular microbiologist, Dr. Andrew Edwards, said.

“So it’s not surprising that drinking vessels are covered in microbes.”

And while bottles may serve as a breeding ground for high numbers of bacteria, University of Reading microbiologist Dr. Simon Clarke said “it’s not necessarily dangerous”.“I’ve never heard of someone getting sick from a water bottle. Similarly, taps are clearly not a problem: when did you last hear of someone getting ill from pouring a glass of water from a tap?

“Water bottles are likely to be contaminated with the bacteria that are already in people’s mouths.”

Squeeze-top bottles were ultimately the cleanest of the three styles tested, with a tenth of the amount of bacteria as one with a screw-top or straw-fitted lid.

Suffice to say, cleaning your bottle needs to be a part of your daily routine.

Experts recommend washing it at least once a day with hot soapy water, and sanitizing it at least once a week – though increase the habit if you’ve been unwell, drink from it while eating, or are filling it with something other than water.