"We’ve seen bacteria such as E. coli, Staphylococcus aureus and Pseudomonas species in poorly cleaned bottles. For most healthy people this may only cause mild symptoms like nausea or stomach upset, but for vulnerable groups, including children, pregnant women, older adults, or those with weakened immune systems, the risks can be far more serious.
"That’s why cleaning should be done daily, not occasionally. Ideally, bottles should be washed after every use with hot soapy water and a bottle brush. Lids, seals and mouthpieces need just as much attention. Everything should then be fully air-dried, because moisture encourages bacteria to grow back quickly.
"If a bottle smells bad, looks cloudy, has visible mould, or develops a slimy film, it may no longer be safe to use. Plastic bottles are particularly prone to scratches that can trap bacteria, which is why stainless steel or glass is often a better option.
"At the end of the day, a dirty water bottle can become a constant source of bacteria exposure. Good hygiene is a simple but important way to reduce that risk.”
