Every time you take a sip from your reusable water bottle, you are depositing bacteria inside, and over the course of a day these can multiply by the millions, scientists warn. A study by Purdue University found that many users have poor cleaning habits, leading to a significant bacterial build-up.
Carl Behnke, a food safety expert at Purdue, conducted a study where passers-by lent their bottles for testing. Many participants declined to learn the results, suspecting their cleaning routines were inadequate. The findings confirmed that bottles were brimming with bacteria.
Primrose Freestone, associate professor in clinical microbiology at the University of Leicester, explains that bacteria thrive at room temperature. A study in Singapore found that bacteria in bottles used by adults grew from around 75,000 per millilitre in mid-morning to over 1-2 million per millilitre within 24 hours. Storing bottles in the fridge can slow growth but not stop it.
Most contamination comes from the drinker's mouth and hands. Bacteria such as E. coli can be introduced through poor hand hygiene. Sharing bottles can also spread viruses like norovirus. Drinks containing sugar or protein, such as protein shakes, further encourage bacterial and fungal growth.
To minimise risks, experts recommend washing bottles daily with hot, soapy water and allowing them to dry completely. Avoid leaving water in bottles for extended periods and refrain from sharing them with others.
