Scientists now have the dirt on the rubber ducky: Those cute yellow bathtime toys are — as some parents have long suspected — a haven for nasty bugs.
Swiss and American researchers counted the microbes swimming inside the toys and said the murky liquid released when ducks were squeezed contained “potentially pathogenic bacteria” in four out of the five toys studied.
The bacteria found included legionella, which can cause respiratory illnesses such as legionnaire’s disease and pseudomonas aeruginosa, a bacterium “often implicated in hospital-acquired infections”.
The study by the Swiss Federal Institute of Aquatic Science and Technology, ETH Zurich and the University of Illinois was published in the journal Biofilms and Microbiomes. It is described as one of the first in-depth scientific examinations of its kind.
The scientists found a strikingly high volume — up to 75 million cells per square centimetre — and variety of bacteria and fungus living inside the ducks.
Tap water does not usually foster the growth of bacteria, the scientists said, but low-quality polymers in the plastic materials gave them the nutrients they need.
Bodily fluids — like urine and sweat — as well as contaminants and even soap in bathwater add microbes and nutrients like nitrogen and phosphorus and create balmy brine for bacteria.
“We’ve found very big differences between different bath animals,” said microbiologist and lead study author Lisa Neu, alluding to other types of bath toys — like rubber crocodiles — that were also examined.
“One of the reasons was the material, because it releases carbon that can serve as food for the bacteria,” she said.
While certain amounts of bacteria can help strengthen children’s immune systems, they can also lead to eye, ear and intestinal infections, the researchers said.
Among the vulnerable users are children, particularly if they enjoy squirting water from bath toys into their faces.
The scientists say using higher-quality polymers to make the ducks could prevent bacterial and fungal growth.
Known for their squeaks and eulogised in a Sesame Street song on TV, rubber duckies have been a childhood bathtime staple for years.
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