Although the cute yellow toys have been a staple at bath time for generations, the research indicates that the plastic provides ideal conditions for bacterial and fungal growth.
The bacteria discovered when ducks were squeezed included Legionella and Pseudomonas aeruginosa, a bacterium which is “often implicated in hospital-acquired infections”.
Although certain amounts of bacteria can actually help to strengthen a child’s immune system, they can lead to eye, ear and intestinal infections.
The study was conducted by the Swiss Federal Institute of Aquatic Science and Technology, ETH Zurich and the University of Illinois.
Scientists exposed some toys to clean bathwater and others to dirty bathwater over an 11-week period.
The researchers said: “During bathing, other key nutrients such as nitrogen and phosphorus, as well as additional bacteria, are contributed by the human body (body fluids such as urine and sweat), external contaminants and personal care products.”
More from UK
Manchester Arena attack: Fire service ‘failed’
‘Teacher’ who trained kids for terror attacks jailed for 25 years
Freezing temperatures and snow over Easter weekend
‘Strong signal to Kremlin’ as NATO and 26 countries expel Russian diplomats
PM wants to mark NHS anniversary with ‘long-term’ NHS funding plan this year
Great Ormond Street keeps £530,000 Presidents Club cash
This, when combined with warm water and the low-quality polymers often used to create rubber ducks, is responsible for bacteria and fungi multiplying inside a toy that children often enjoy using to squirt water in their faces.
Despite the alarming findings, this may not be the beginning of the end for the rubber duck. Researchers say bath toys made of higher-quality polymers would be less susceptible to unpleasant growths.