Reusable water bottles have 40,000 times more bacteria than a toilet seat: Study

A recent study from US-based waterfilterguru.com found reusable bottles can harbour 40,000 times more bacteria than the average toilet seat – describing them as being like a "portable Petri dish," reported the New York Post.

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

A comparison between bacteria on bottles and other household objects

Bottles contain twice as germs as the kitchen sink; can carry four times the amount of bacteria as a computer mouse; and 14 times more than a pet's drinking bowl!

How dangerous are these bacteria present on bottles?

"The human mouth is home to a large number and range of different bacteria," Imperial College London molecular microbiologist, Dr. Andrew Edwards told NY post.

"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 adding "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."

Which type of bottle was the safest?

Squeeze-top bottles were 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.

How often should the bottles be cleaned?

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.