Reusable drinks bottles may carry more bacteria than a toilet seat, a new study has found, casting shade on an item that has become for many a lifestyle accessory, signalling green and healthy credentials, and personalising hydration.
Research by US-based water treatment firm, WaterFilterGuru.com, shows reusable bottles host on average 40,000 times more colony-forming units (CFUs) of bacteria than the average toilet seat. Spout-top and screw-top lids contained the most bacteria of all the water bottles, with 30 million CFUs each—that’s three times as much as a kitchen sink.
The germs found in the bottles fell into two categories: gram-negative rods and bacilli. Gram-negative bacteria are behind increasingly antibiotic-resistant infections, while bacilli can cause gastrointestinal problems.
Pointing out that the “same vessel that brings healthy hydration to your daily routine could make you sick if not cared for properly,” WaterFilterGuru notes that “experts recommend washing your water bottle once a day and sanitising it at least once a week.” Cleaning should increase if you’ve been sick, eaten food while drinking, or put sugary drinks in the bottle.
Over 60% of the one thousand respondents to the survey were in line with those recommendations, reporting they clean their water bottles once or more per day. A quarter of Americans wash their bottle a few times a week, and 10% only do so a few times a month.
For travellers, the advice to clean a water bottle at least once a day holds, but caution should be exercised depending on how certain you are of the cleanliness of the water used for washing. The researchers urge people to be “mindful of the water you’re putting into your reusable bottle. It might look clean, but inadequately treated water or contaminated pipes can decrease the safety of your drinking water.” And bear in mind, the practical advice of University of Reading microbiologist, Simon Clarke, who argues the germs on bottles are “not necessarily dangerous,” as they are mostly made up of bacteria already in the users’ mouth.
The study recommends using filtered and sanitised water from a home source that is dependable—but that approach is not always possible on the move. Travellers to remote places or destinations where water infrastructure might not be optimal can pack water purification tablets to take with them.
It turns out the choice of water bottle is also important for those wanting to maximise hygiene. Respondents showed a strong preference (44%) for stainless steel bottles, especially Hydro Flasks, while preferences for squeeze or screw tops were divided by generation. Screw-top lids are the favourite among baby boomers (42%) and Gen Z (39%), while Gen X (48%) and Millennials (42%) prefer screw-top lids.
The big news is that squeeze-top bottles were found to be the cleanest by the researchers, having only a tenth of the amount of bacteria found on spout and screw top vessels, so acquiring a squeeze-top bottle could be an important step for travellers and anyone who risks not being able to clean their bottle as often as they would like.
