Should rubber ducks be banned from the bath?

A group of Swiss and US researchers have delved into “the dark side” of inviting rubber ducks and other flexible plastic toys into our tubs.

Any plastic materials dunked in bathwater provide ideal conditions for bacterial and fungal growth, according to the conclusions of the joint study, published Tuesday by the Swiss government.

“Dense growths of bacteria and fungi are found on the inner surface of these flexible toys, and a murky liquid will often be released when they are squeezed by a child,” the Swiss government statement said.

The researchers from the Swiss Federal Institute of Aquatic Science and Technology EAWAG, the Swiss Federal Polytechnic School and the University of Illinois found that “diverse microbial growth is promoted not only by the plastic materials but by bath users themselves.”

The researchers stressed though that there was a big difference between the plastic toys exposed to different types of water.

“Fungal species were detected in almost 60 percent of the real bath toys and in all the dirty-water control toys,” the statement said.

“Potentially pathogenic bacteria were identified in 80 percent of all the toys studied, including Legionella and Pseudomonas aeruginosa,” which is often the culprit in hospital-acquired infections, it added.

The main problem is that warm water gathers inside the toy, often made of low-quality polymers, which release organic carbon compounds that serve as nutrients to growing bacteria colonies.

This allows bacteria and fungi to multiply inside of a toy children often enjoy using to squirt water into their faces.

“This could strengthen the immune system, which would be positive, but it can also result in eye, ear, or even gastrointestinal infections,” said Tuesday’s statement, which suggests tighter regulations on the polymeric materials used to produce bath toys.