Lots of Singaporeans carry water bottles, but how many are aware of the bacteria and mould we gulp down with every use? The programme Talking Point examines common hygiene habits and how to avoid potential health risks.
Many water bottles to choose from, but did you know the bottle’s material can affect the bacteria build-up? polyprop pipe
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SINGAPORE: As temperatures soar and Singaporeans swelter, venturing outside often necessitates a water bottle at hand. Experts warn, however, that our reusable bottles might be dirtier than we realise.
Infrequent and insufficient cleaning can turn trusty bottles into Trojan horses for bacteria and mould. Even the top hydration brands — like Owala, Hydroflask and Stanley — are not exempt from the multitude of germs.
A consumer study in the United States has suggested that reusable water bottles could gather more bacteria than a kitchen sink, computer mouse or even a toilet seat.
“When we consume food, we have food particles in our mouth. And once we bring this water bottle to our mouth to drink, … some of them can get stuck within the water bottle,” said water quality expert Kwok Chen Ko.
WATCH: Is your reusable water bottle a hotbed of harmful bacteria and mould? (21:58)
Bacteria and mould are then free to feast on these deposits, especially in the absence of “a thorough washing”.
So what qualifies as “thorough”, and how many of us are truly safeguarding our sips? The programme Talking Point investigates misconceptions about bottle hygiene and the stark realities that follow.
Some users of reusable water bottles had theirs tested in a lab to find out for themselves. Ang Teck Kuan, for one, did not expect his bottle to have the most bacteria and mould.
“I only drink plain water from it,” he countered.
At first glance, there seems to be some truth to his theory. Sugars and fats found in common beverages, such as tea, coffee, and syrups, accumulate in water bottles more easily, creating conditions conducive to bacterial and mould growth.
But the absence of such substances does not inherently prevent germ cultivation.
A bottle that was used simply to store water in the fridge, for example, had the highest mould count — because mould thrives in moist environments, and the bottle was rarely washed.
More than one Talking Point viewer, however, had put their faith in plain water.
Trixie Ong and Joshua Sim, who occasionally added other drinks to their bottles, were rinsing them with water daily and washing with soap once a week or less.
Their bottles tallied bacteria-cum-mould scores of 90,303 and 71,801 respectively, beyond the recommended limit of 55,000.
Wennie Chia, on the other hand, removes the various parts of her bottle for a soapy scrub every other day. She had a bacteria-cum-mould score of 11,338, the lowest among the 10 water bottles that were tested.
At a broader level, a Talking Point poll showed that 52 per cent of 1,100-plus respondents on Instagram washed their bottles daily, 19 per cent did so twice or thrice weekly and 18 per cent said once a week.
And 11 per cent said once a month.
Bottles should be washed daily, said Kwok. But even that might not suffice if only rinsed with water or done ineffectively.
He recommends “using a brush with detergent” to scrub the water bottle inside and outside, paying “special attention” to areas with lip contact, like bottle rims and caps.
It could be a challenge cleaning straws and narrow-mouthed bottles, and he does not recommend using the latter. What is important is to get a brush of the right size, such as a wire brush for straws.
Adison Wong, a Singapore Institute of Technology associate professor, emphasised that certain bacteria, like pseudomonas and cyanobacteria, are cause for wariness.
When ingested, the latter “can lead to abdominal pain, nausea (and) diarrhoea”, while the former can cause a respiratory tract infection if they reach the lungs through the oral cavity.
While these health hazards are largely invisible, you can look out for a gooey coating that often emits an unpleasant odour, for signs of microbial colonisation.
Known as a biofilm, “it’s a sort of shelter for the microbes to thrive in and grow freely”, Wong said.
According to Nanyang Technological University associate professor Sierin Lim, the material of your water bottle also affects the extent of bacterial and mould cultivation.
The bioengineer illustrated with an experiment that glass has the slowest colony-forming rate, followed by polypropylene, stainless steel and finally polycarbonate, which is a strong, transparent type of plastic.
As to why polypropylene and polycarbonate ranked differently even though both are plastics, she referred to the distinct properties of each surface.
“Polypropylene has lower wettability compared to polycarbonate, which means that polypropylene will repel more water, while polycarbonate will attract water,” she said.
Besides wettability, what will attract microbes are textured surfaces and porous material, as “bacteria like to hide in the crevices of the surface”.
Therefore, a less porous and less textured surface like glass is more impervious to the growth of bacteria and mould.
Still, Lim said other factors can come into play in the likelihood of bacterial and mould growth. A bottle that is easy to clean, and an owner who is willing to clean it sufficiently, is a good place to start.
Watch this episode of Talking Point here. The programme airs on Channel 5 every Thursday at 9:30 p.m.
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